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Diffstat (limited to 'src/vdbesort.c')
| -rw-r--r-- | src/vdbesort.c | 2526 |
1 files changed, 1975 insertions, 551 deletions
diff --git a/src/vdbesort.c b/src/vdbesort.c index 6a5855f2e..7318ea409 100644 --- a/src/vdbesort.c +++ b/src/vdbesort.c @@ -1,5 +1,5 @@ /* -** 2011 July 9 +** 2011-07-09 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: @@ -10,44 +10,198 @@ ** ************************************************************************* ** This file contains code for the VdbeSorter object, used in concert with -** a VdbeCursor to sort large numbers of keys (as may be required, for -** example, by CREATE INDEX statements on tables too large to fit in main -** memory). +** a VdbeCursor to sort large numbers of keys for CREATE INDEX statements +** or by SELECT statements with ORDER BY clauses that cannot be satisfied +** using indexes and without LIMIT clauses. +** +** The VdbeSorter object implements a multi-threaded external merge sort +** algorithm that is efficient even if the number of elements being sorted +** exceeds the available memory. +** +** Here is the (internal, non-API) interface between this module and the +** rest of the SQLite system: +** +** sqlite3VdbeSorterInit() Create a new VdbeSorter object. +** +** sqlite3VdbeSorterWrite() Add a single new row to the VdbeSorter +** object. The row is a binary blob in the +** OP_MakeRecord format that contains both +** the ORDER BY key columns and result columns +** in the case of a SELECT w/ ORDER BY, or +** the complete record for an index entry +** in the case of a CREATE INDEX. +** +** sqlite3VdbeSorterRewind() Sort all content previously added. +** Position the read cursor on the +** first sorted element. +** +** sqlite3VdbeSorterNext() Advance the read cursor to the next sorted +** element. +** +** sqlite3VdbeSorterRowkey() Return the complete binary blob for the +** row currently under the read cursor. +** +** sqlite3VdbeSorterCompare() Compare the binary blob for the row +** currently under the read cursor against +** another binary blob X and report if +** X is strictly less than the read cursor. +** Used to enforce uniqueness in a +** CREATE UNIQUE INDEX statement. +** +** sqlite3VdbeSorterClose() Close the VdbeSorter object and reclaim +** all resources. +** +** sqlite3VdbeSorterReset() Refurbish the VdbeSorter for reuse. This +** is like Close() followed by Init() only +** much faster. +** +** The interfaces above must be called in a particular order. Write() can +** only occur in between Init()/Reset() and Rewind(). Next(), Rowkey(), and +** Compare() can only occur in between Rewind() and Close()/Reset(). i.e. +** +** Init() +** for each record: Write() +** Rewind() +** Rowkey()/Compare() +** Next() +** Close() +** +** Algorithm: +** +** Records passed to the sorter via calls to Write() are initially held +** unsorted in main memory. Assuming the amount of memory used never exceeds +** a threshold, when Rewind() is called the set of records is sorted using +** an in-memory merge sort. In this case, no temporary files are required +** and subsequent calls to Rowkey(), Next() and Compare() read records +** directly from main memory. +** +** If the amount of space used to store records in main memory exceeds the +** threshold, then the set of records currently in memory are sorted and +** written to a temporary file in "Packed Memory Array" (PMA) format. +** A PMA created at this point is known as a "level-0 PMA". Higher levels +** of PMAs may be created by merging existing PMAs together - for example +** merging two or more level-0 PMAs together creates a level-1 PMA. +** +** The threshold for the amount of main memory to use before flushing +** records to a PMA is roughly the same as the limit configured for the +** page-cache of the main database. Specifically, the threshold is set to +** the value returned by "PRAGMA main.page_size" multipled by +** that returned by "PRAGMA main.cache_size", in bytes. +** +** If the sorter is running in single-threaded mode, then all PMAs generated +** are appended to a single temporary file. Or, if the sorter is running in +** multi-threaded mode then up to (N+1) temporary files may be opened, where +** N is the configured number of worker threads. In this case, instead of +** sorting the records and writing the PMA to a temporary file itself, the +** calling thread usually launches a worker thread to do so. Except, if +** there are already N worker threads running, the main thread does the work +** itself. +** +** The sorter is running in multi-threaded mode if (a) the library was built +** with pre-processor symbol SQLITE_MAX_WORKER_THREADS set to a value greater +** than zero, and (b) worker threads have been enabled at runtime by calling +** sqlite3_config(SQLITE_CONFIG_WORKER_THREADS, ...). +** +** When Rewind() is called, any data remaining in memory is flushed to a +** final PMA. So at this point the data is stored in some number of sorted +** PMAs within temporary files on disk. +** +** If there are fewer than SORTER_MAX_MERGE_COUNT PMAs in total and the +** sorter is running in single-threaded mode, then these PMAs are merged +** incrementally as keys are retreived from the sorter by the VDBE. The +** MergeEngine object, described in further detail below, performs this +** merge. +** +** Or, if running in multi-threaded mode, then a background thread is +** launched to merge the existing PMAs. Once the background thread has +** merged T bytes of data into a single sorted PMA, the main thread +** begins reading keys from that PMA while the background thread proceeds +** with merging the next T bytes of data. And so on. +** +** Parameter T is set to half the value of the memory threshold used +** by Write() above to determine when to create a new PMA. +** +** If there are more than SORTER_MAX_MERGE_COUNT PMAs in total when +** Rewind() is called, then a hierarchy of incremental-merges is used. +** First, T bytes of data from the first SORTER_MAX_MERGE_COUNT PMAs on +** disk are merged together. Then T bytes of data from the second set, and +** so on, such that no operation ever merges more than SORTER_MAX_MERGE_COUNT +** PMAs at a time. This done is to improve locality. +** +** If running in multi-threaded mode and there are more than +** SORTER_MAX_MERGE_COUNT PMAs on disk when Rewind() is called, then more +** than one background thread may be created. Specifically, there may be +** one background thread for each temporary file on disk, and one background +** thread to merge the output of each of the others to a single PMA for +** the main thread to read from. */ - #include "sqliteInt.h" #include "vdbeInt.h" +/* +** If SQLITE_DEBUG_SORTER_THREADS is defined, this module outputs various +** messages to stderr that may be helpful in understanding the performance +** characteristics of the sorter in multi-threaded mode. +*/ +#if 0 +# define SQLITE_DEBUG_SORTER_THREADS 1 +#endif -typedef struct VdbeSorterIter VdbeSorterIter; -typedef struct SorterRecord SorterRecord; -typedef struct FileWriter FileWriter; +/* +** Private objects used by the sorter +*/ +typedef struct MergeEngine MergeEngine; /* Merge PMAs together */ +typedef struct PmaReader PmaReader; /* Incrementally read one PMA */ +typedef struct PmaWriter PmaWriter; /* Incrementally write one PMA */ +typedef struct SorterRecord SorterRecord; /* A record being sorted */ +typedef struct SortSubtask SortSubtask; /* A sub-task in the sort process */ +typedef struct SorterFile SorterFile; /* Temporary file object wrapper */ +typedef struct SorterList SorterList; /* In-memory list of records */ +typedef struct IncrMerger IncrMerger; /* Read & merge multiple PMAs */ /* -** NOTES ON DATA STRUCTURE USED FOR N-WAY MERGES: +** A container for a temp file handle and the current amount of data +** stored in the file. +*/ +struct SorterFile { + sqlite3_file *pFd; /* File handle */ + i64 iEof; /* Bytes of data stored in pFd */ +}; + +/* +** An in-memory list of objects to be sorted. ** -** As keys are added to the sorter, they are written to disk in a series -** of sorted packed-memory-arrays (PMAs). The size of each PMA is roughly -** the same as the cache-size allowed for temporary databases. In order -** to allow the caller to extract keys from the sorter in sorted order, -** all PMAs currently stored on disk must be merged together. This comment -** describes the data structure used to do so. The structure supports -** merging any number of arrays in a single pass with no redundant comparison -** operations. +** If aMemory==0 then each object is allocated separately and the objects +** are connected using SorterRecord.u.pNext. If aMemory!=0 then all objects +** are stored in the aMemory[] bulk memory, one right after the other, and +** are connected using SorterRecord.u.iNext. +*/ +struct SorterList { + SorterRecord *pList; /* Linked list of records */ + u8 *aMemory; /* If non-NULL, bulk memory to hold pList */ + int szPMA; /* Size of pList as PMA in bytes */ +}; + +/* +** The MergeEngine object is used to combine two or more smaller PMAs into +** one big PMA using a merge operation. Separate PMAs all need to be +** combined into one big PMA in order to be able to step through the sorted +** records in order. ** -** The aIter[] array contains an iterator for each of the PMAs being merged. -** An aIter[] iterator either points to a valid key or else is at EOF. For -** the purposes of the paragraphs below, we assume that the array is actually -** N elements in size, where N is the smallest power of 2 greater to or equal -** to the number of iterators being merged. The extra aIter[] elements are -** treated as if they are empty (always at EOF). +** The aReadr[] array contains a PmaReader object for each of the PMAs being +** merged. An aReadr[] object either points to a valid key or else is at EOF. +** ("EOF" means "End Of File". When aReadr[] is at EOF there is no more data.) +** For the purposes of the paragraphs below, we assume that the array is +** actually N elements in size, where N is the smallest power of 2 greater +** to or equal to the number of PMAs being merged. The extra aReadr[] elements +** are treated as if they are empty (always at EOF). ** ** The aTree[] array is also N elements in size. The value of N is stored in -** the VdbeSorter.nTree variable. +** the MergeEngine.nTree variable. ** ** The final (N/2) elements of aTree[] contain the results of comparing -** pairs of iterator keys together. Element i contains the result of -** comparing aIter[2*i-N] and aIter[2*i-N+1]. Whichever key is smaller, the +** pairs of PMA keys together. Element i contains the result of +** comparing aReadr[2*i-N] and aReadr[2*i-N+1]. Whichever key is smaller, the ** aTree element is set to the index of it. ** ** For the purposes of this comparison, EOF is considered greater than any @@ -55,34 +209,34 @@ typedef struct FileWriter FileWriter; ** values), it doesn't matter which index is stored. ** ** The (N/4) elements of aTree[] that precede the final (N/2) described -** above contains the index of the smallest of each block of 4 iterators. -** And so on. So that aTree[1] contains the index of the iterator that +** above contains the index of the smallest of each block of 4 PmaReaders +** And so on. So that aTree[1] contains the index of the PmaReader that ** currently points to the smallest key value. aTree[0] is unused. ** ** Example: ** -** aIter[0] -> Banana -** aIter[1] -> Feijoa -** aIter[2] -> Elderberry -** aIter[3] -> Currant -** aIter[4] -> Grapefruit -** aIter[5] -> Apple -** aIter[6] -> Durian -** aIter[7] -> EOF +** aReadr[0] -> Banana +** aReadr[1] -> Feijoa +** aReadr[2] -> Elderberry +** aReadr[3] -> Currant +** aReadr[4] -> Grapefruit +** aReadr[5] -> Apple +** aReadr[6] -> Durian +** aReadr[7] -> EOF ** ** aTree[] = { X, 5 0, 5 0, 3, 5, 6 } ** ** The current element is "Apple" (the value of the key indicated by -** iterator 5). When the Next() operation is invoked, iterator 5 will +** PmaReader 5). When the Next() operation is invoked, PmaReader 5 will ** be advanced to the next key in its segment. Say the next key is ** "Eggplant": ** -** aIter[5] -> Eggplant +** aReadr[5] -> Eggplant ** -** The contents of aTree[] are updated first by comparing the new iterator -** 5 key to the current key of iterator 4 (still "Grapefruit"). The iterator +** The contents of aTree[] are updated first by comparing the new PmaReader +** 5 key to the current key of PmaReader 4 (still "Grapefruit"). The PmaReader ** 5 value is still smaller, so aTree[6] is set to 5. And so on up the tree. -** The value of iterator 6 - "Durian" - is now smaller than that of iterator +** The value of PmaReader 6 - "Durian" - is now smaller than that of PmaReader ** 5, so aTree[3] is set to 6. Key 0 is smaller than key 6 (Banana<Durian), ** so the value written into element 1 of the array is 0. As follows: ** @@ -92,97 +246,246 @@ typedef struct FileWriter FileWriter; ** key comparison operations are required, where N is the number of segments ** being merged (rounded up to the next power of 2). */ +struct MergeEngine { + int nTree; /* Used size of aTree/aReadr (power of 2) */ + SortSubtask *pTask; /* Used by this thread only */ + int *aTree; /* Current state of incremental merge */ + PmaReader *aReadr; /* Array of PmaReaders to merge data from */ +}; + +/* +** This object represents a single thread of control in a sort operation. +** Exactly VdbeSorter.nTask instances of this object are allocated +** as part of each VdbeSorter object. Instances are never allocated any +** other way. VdbeSorter.nTask is set to the number of worker threads allowed +** (see SQLITE_CONFIG_WORKER_THREADS) plus one (the main thread). Thus for +** single-threaded operation, there is exactly one instance of this object +** and for multi-threaded operation there are two or more instances. +** +** Essentially, this structure contains all those fields of the VdbeSorter +** structure for which each thread requires a separate instance. For example, +** each thread requries its own UnpackedRecord object to unpack records in +** as part of comparison operations. +** +** Before a background thread is launched, variable bDone is set to 0. Then, +** right before it exits, the thread itself sets bDone to 1. This is used for +** two purposes: +** +** 1. When flushing the contents of memory to a level-0 PMA on disk, to +** attempt to select a SortSubtask for which there is not already an +** active background thread (since doing so causes the main thread +** to block until it finishes). +** +** 2. If SQLITE_DEBUG_SORTER_THREADS is defined, to determine if a call +** to sqlite3ThreadJoin() is likely to block. Cases that are likely to +** block provoke debugging output. +** +** In both cases, the effects of the main thread seeing (bDone==0) even +** after the thread has finished are not dire. So we don't worry about +** memory barriers and such here. +*/ +struct SortSubtask { + SQLiteThread *pThread; /* Background thread, if any */ + int bDone; /* Set if thread is finished but not joined */ + VdbeSorter *pSorter; /* Sorter that owns this sub-task */ + UnpackedRecord *pUnpacked; /* Space to unpack a record */ + SorterList list; /* List for thread to write to a PMA */ + int nPMA; /* Number of PMAs currently in file */ + SorterFile file; /* Temp file for level-0 PMAs */ + SorterFile file2; /* Space for other PMAs */ +}; + +/* +** Main sorter structure. A single instance of this is allocated for each +** sorter cursor created by the VDBE. +** +** mxKeysize: +** As records are added to the sorter by calls to sqlite3VdbeSorterWrite(), +** this variable is updated so as to be set to the size on disk of the +** largest record in the sorter. +*/ struct VdbeSorter { - i64 iWriteOff; /* Current write offset within file pTemp1 */ - i64 iReadOff; /* Current read offset within file pTemp1 */ - int nInMemory; /* Current size of pRecord list as PMA */ - int nTree; /* Used size of aTree/aIter (power of 2) */ - int nPMA; /* Number of PMAs stored in pTemp1 */ int mnPmaSize; /* Minimum PMA size, in bytes */ int mxPmaSize; /* Maximum PMA size, in bytes. 0==no limit */ - VdbeSorterIter *aIter; /* Array of iterators to merge */ - int *aTree; /* Current state of incremental merge */ - sqlite3_file *pTemp1; /* PMA file 1 */ - SorterRecord *pRecord; /* Head of in-memory record list */ - UnpackedRecord *pUnpacked; /* Used to unpack keys */ + int mxKeysize; /* Largest serialized key seen so far */ + int pgsz; /* Main database page size */ + PmaReader *pReader; /* Readr data from here after Rewind() */ + MergeEngine *pMerger; /* Or here, if bUseThreads==0 */ + sqlite3 *db; /* Database connection */ + KeyInfo *pKeyInfo; /* How to compare records */ + UnpackedRecord *pUnpacked; /* Used by VdbeSorterCompare() */ + SorterList list; /* List of in-memory records */ + int iMemory; /* Offset of free space in list.aMemory */ + int nMemory; /* Size of list.aMemory allocation in bytes */ + u8 bUsePMA; /* True if one or more PMAs created */ + u8 bUseThreads; /* True to use background threads */ + u8 iPrev; /* Previous thread used to flush PMA */ + u8 nTask; /* Size of aTask[] array */ + SortSubtask aTask[1]; /* One or more subtasks */ }; /* -** The following type is an iterator for a PMA. It caches the current key in -** variables nKey/aKey. If the iterator is at EOF, pFile==0. +** An instance of the following object is used to read records out of a +** PMA, in sorted order. The next key to be read is cached in nKey/aKey. +** aKey might point into aMap or into aBuffer. If neither of those locations +** contain a contiguous representation of the key, then aAlloc is allocated +** and the key is copied into aAlloc and aKey is made to poitn to aAlloc. +** +** pFd==0 at EOF. +*/ +struct PmaReader { + i64 iReadOff; /* Current read offset */ + i64 iEof; /* 1 byte past EOF for this PmaReader */ + int nAlloc; /* Bytes of space at aAlloc */ + int nKey; /* Number of bytes in key */ + sqlite3_file *pFd; /* File handle we are reading from */ + u8 *aAlloc; /* Space for aKey if aBuffer and pMap wont work */ + u8 *aKey; /* Pointer to current key */ + u8 *aBuffer; /* Current read buffer */ + int nBuffer; /* Size of read buffer in bytes */ + u8 *aMap; /* Pointer to mapping of entire file */ + IncrMerger *pIncr; /* Incremental merger */ +}; + +/* +** Normally, a PmaReader object iterates through an existing PMA stored +** within a temp file. However, if the PmaReader.pIncr variable points to +** an object of the following type, it may be used to iterate/merge through +** multiple PMAs simultaneously. +** +** There are two types of IncrMerger object - single (bUseThread==0) and +** multi-threaded (bUseThread==1). +** +** A multi-threaded IncrMerger object uses two temporary files - aFile[0] +** and aFile[1]. Neither file is allowed to grow to more than mxSz bytes in +** size. When the IncrMerger is initialized, it reads enough data from +** pMerger to populate aFile[0]. It then sets variables within the +** corresponding PmaReader object to read from that file and kicks off +** a background thread to populate aFile[1] with the next mxSz bytes of +** sorted record data from pMerger. +** +** When the PmaReader reaches the end of aFile[0], it blocks until the +** background thread has finished populating aFile[1]. It then exchanges +** the contents of the aFile[0] and aFile[1] variables within this structure, +** sets the PmaReader fields to read from the new aFile[0] and kicks off +** another background thread to populate the new aFile[1]. And so on, until +** the contents of pMerger are exhausted. +** +** A single-threaded IncrMerger does not open any temporary files of its +** own. Instead, it has exclusive access to mxSz bytes of space beginning +** at offset iStartOff of file pTask->file2. And instead of using a +** background thread to prepare data for the PmaReader, with a single +** threaded IncrMerger the allocate part of pTask->file2 is "refilled" with +** keys from pMerger by the calling thread whenever the PmaReader runs out +** of data. */ -struct VdbeSorterIter { - i64 iReadOff; /* Current read offset */ - i64 iEof; /* 1 byte past EOF for this iterator */ - int nAlloc; /* Bytes of space at aAlloc */ - int nKey; /* Number of bytes in key */ - sqlite3_file *pFile; /* File iterator is reading from */ - u8 *aAlloc; /* Allocated space */ - u8 *aKey; /* Pointer to current key */ - u8 *aBuffer; /* Current read buffer */ - int nBuffer; /* Size of read buffer in bytes */ +struct IncrMerger { + SortSubtask *pTask; /* Task that owns this merger */ + MergeEngine *pMerger; /* Merge engine thread reads data from */ + i64 iStartOff; /* Offset to start writing file at */ + int mxSz; /* Maximum bytes of data to store */ + int bEof; /* Set to true when merge is finished */ + int bUseThread; /* True to use a bg thread for this object */ + SorterFile aFile[2]; /* aFile[0] for reading, [1] for writing */ }; /* -** An instance of this structure is used to organize the stream of records -** being written to files by the merge-sort code into aligned, page-sized -** blocks. Doing all I/O in aligned page-sized blocks helps I/O to go -** faster on many operating systems. +** An instance of this object is used for writing a PMA. +** +** The PMA is written one record at a time. Each record is of an arbitrary +** size. But I/O is more efficient if it occurs in page-sized blocks where +** each block is aligned on a page boundary. This object caches writes to +** the PMA so that aligned, page-size blocks are written. */ -struct FileWriter { +struct PmaWriter { int eFWErr; /* Non-zero if in an error state */ u8 *aBuffer; /* Pointer to write buffer */ int nBuffer; /* Size of write buffer in bytes */ int iBufStart; /* First byte of buffer to write */ int iBufEnd; /* Last byte of buffer to write */ i64 iWriteOff; /* Offset of start of buffer in file */ - sqlite3_file *pFile; /* File to write to */ + sqlite3_file *pFd; /* File handle to write to */ }; /* -** A structure to store a single record. All in-memory records are connected -** together into a linked list headed at VdbeSorter.pRecord using the -** SorterRecord.pNext pointer. +** This object is the header on a single record while that record is being +** held in memory and prior to being written out as part of a PMA. +** +** How the linked list is connected depends on how memory is being managed +** by this module. If using a separate allocation for each in-memory record +** (VdbeSorter.list.aMemory==0), then the list is always connected using the +** SorterRecord.u.pNext pointers. +** +** Or, if using the single large allocation method (VdbeSorter.list.aMemory!=0), +** then while records are being accumulated the list is linked using the +** SorterRecord.u.iNext offset. This is because the aMemory[] array may +** be sqlite3Realloc()ed while records are being accumulated. Once the VM +** has finished passing records to the sorter, or when the in-memory buffer +** is full, the list is sorted. As part of the sorting process, it is +** converted to use the SorterRecord.u.pNext pointers. See function +** vdbeSorterSort() for details. */ struct SorterRecord { - void *pVal; - int nVal; - SorterRecord *pNext; + int nVal; /* Size of the record in bytes */ + union { + SorterRecord *pNext; /* Pointer to next record in list */ + int iNext; /* Offset within aMemory of next record */ + } u; + /* The data for the record immediately follows this header */ }; -/* Minimum allowable value for the VdbeSorter.nWorking variable */ +/* Return a pointer to the buffer containing the record data for SorterRecord +** object p. Should be used as if: +** +** void *SRVAL(SorterRecord *p) { return (void*)&p[1]; } +*/ +#define SRVAL(p) ((void*)((SorterRecord*)(p) + 1)) + +/* The minimum PMA size is set to this value multiplied by the database +** page size in bytes. */ #define SORTER_MIN_WORKING 10 -/* Maximum number of segments to merge in a single pass. */ +/* Maximum number of PMAs that a single MergeEngine can merge */ #define SORTER_MAX_MERGE_COUNT 16 +static int vdbeIncrSwap(IncrMerger*); +static void vdbeIncrFree(IncrMerger *); + /* -** Free all memory belonging to the VdbeSorterIter object passed as the second +** Free all memory belonging to the PmaReader object passed as the ** argument. All structure fields are set to zero before returning. */ -static void vdbeSorterIterZero(sqlite3 *db, VdbeSorterIter *pIter){ - sqlite3DbFree(db, pIter->aAlloc); - sqlite3DbFree(db, pIter->aBuffer); - memset(pIter, 0, sizeof(VdbeSorterIter)); +static void vdbePmaReaderClear(PmaReader *pReadr){ + sqlite3_free(pReadr->aAlloc); + sqlite3_free(pReadr->aBuffer); + if( pReadr->aMap ) sqlite3OsUnfetch(pReadr->pFd, 0, pReadr->aMap); + vdbeIncrFree(pReadr->pIncr); + memset(pReadr, 0, sizeof(PmaReader)); } /* -** Read nByte bytes of data from the stream of data iterated by object p. +** Read the next nByte bytes of data from the PMA p. ** If successful, set *ppOut to point to a buffer containing the data ** and return SQLITE_OK. Otherwise, if an error occurs, return an SQLite ** error code. ** -** The buffer indicated by *ppOut may only be considered valid until the +** The buffer returned in *ppOut is only valid until the ** next call to this function. */ -static int vdbeSorterIterRead( - sqlite3 *db, /* Database handle (for malloc) */ - VdbeSorterIter *p, /* Iterator */ +static int vdbePmaReadBlob( + PmaReader *p, /* PmaReader from which to take the blob */ int nByte, /* Bytes of data to read */ u8 **ppOut /* OUT: Pointer to buffer containing data */ ){ int iBuf; /* Offset within buffer to read from */ int nAvail; /* Bytes of data available in buffer */ + + if( p->aMap ){ + *ppOut = &p->aMap[p->iReadOff]; + p->iReadOff += nByte; + return SQLITE_OK; + } + assert( p->aBuffer ); /* If there is no more data to be read from the buffer, read the next @@ -201,8 +504,8 @@ static int vdbeSorterIterRead( } assert( nRead>0 ); - /* Read data from the file. Return early if an error occurs. */ - rc = sqlite3OsRead(p->pFile, p->aBuffer, nRead, p->iReadOff); + /* Readr data from the file. Return early if an error occurs. */ + rc = sqlite3OsRead(p->pFd, p->aBuffer, nRead, p->iReadOff); assert( rc!=SQLITE_IOERR_SHORT_READ ); if( rc!=SQLITE_OK ) return rc; } @@ -222,11 +525,13 @@ static int vdbeSorterIterRead( /* Extend the p->aAlloc[] allocation if required. */ if( p->nAlloc<nByte ){ - int nNew = p->nAlloc*2; + u8 *aNew; + int nNew = MAX(128, p->nAlloc*2); while( nByte>nNew ) nNew = nNew*2; - p->aAlloc = sqlite3DbReallocOrFree(db, p->aAlloc, nNew); - if( !p->aAlloc ) return SQLITE_NOMEM; + aNew = sqlite3Realloc(p->aAlloc, nNew); + if( !aNew ) return SQLITE_NOMEM; p->nAlloc = nNew; + p->aAlloc = aNew; } /* Copy as much data as is available in the buffer into the start of @@ -238,13 +543,13 @@ static int vdbeSorterIterRead( /* The following loop copies up to p->nBuffer bytes per iteration into ** the p->aAlloc[] buffer. */ while( nRem>0 ){ - int rc; /* vdbeSorterIterRead() return code */ + int rc; /* vdbePmaReadBlob() return code */ int nCopy; /* Number of bytes to copy */ u8 *aNext; /* Pointer to buffer to copy data from */ nCopy = nRem; if( nRem>p->nBuffer ) nCopy = p->nBuffer; - rc = vdbeSorterIterRead(db, p, nCopy, &aNext); + rc = vdbePmaReadBlob(p, nCopy, &aNext); if( rc!=SQLITE_OK ) return rc; assert( aNext!=p->aAlloc ); memcpy(&p->aAlloc[nByte - nRem], aNext, nCopy); @@ -261,108 +566,171 @@ static int vdbeSorterIterRead( ** Read a varint from the stream of data accessed by p. Set *pnOut to ** the value read. */ -static int vdbeSorterIterVarint(sqlite3 *db, VdbeSorterIter *p, u64 *pnOut){ +static int vdbePmaReadVarint(PmaReader *p, u64 *pnOut){ int iBuf; - iBuf = p->iReadOff % p->nBuffer; - if( iBuf && (p->nBuffer-iBuf)>=9 ){ - p->iReadOff += sqlite3GetVarint(&p->aBuffer[iBuf], pnOut); + if( p->aMap ){ + p->iReadOff += sqlite3GetVarint(&p->aMap[p->iReadOff], pnOut); }else{ - u8 aVarint[16], *a; - int i = 0, rc; - do{ - rc = vdbeSorterIterRead(db, p, 1, &a); - if( rc ) return rc; - aVarint[(i++)&0xf] = a[0]; - }while( (a[0]&0x80)!=0 ); - sqlite3GetVarint(aVarint, pnOut); + iBuf = p->iReadOff % p->nBuffer; + if( iBuf && (p->nBuffer-iBuf)>=9 ){ + p->iReadOff += sqlite3GetVarint(&p->aBuffer[iBuf], pnOut); + }else{ + u8 aVarint[16], *a; + int i = 0, rc; + do{ + rc = vdbePmaReadBlob(p, 1, &a); + if( rc ) return rc; + aVarint[(i++)&0xf] = a[0]; + }while( (a[0]&0x80)!=0 ); + sqlite3GetVarint(aVarint, pnOut); + } } return SQLITE_OK; } +/* +** Attempt to memory map file pFile. If successful, set *pp to point to the +** new mapping and return SQLITE_OK. If the mapping is not attempted +** (because the file is too large or the VFS layer is configured not to use +** mmap), return SQLITE_OK and set *pp to NULL. +** +** Or, if an error occurs, return an SQLite error code. The final value of +** *pp is undefined in this case. +*/ +static int vdbeSorterMapFile(SortSubtask *pTask, SorterFile *pFile, u8 **pp){ + int rc = SQLITE_OK; + if( pFile->iEof<=(i64)(pTask->pSorter->db->nMaxSorterMmap) ){ + rc = sqlite3OsFetch(pFile->pFd, 0, (int)pFile->iEof, (void**)pp); + testcase( rc!=SQLITE_OK ); + } + return rc; +} /* -** Advance iterator pIter to the next key in its PMA. Return SQLITE_OK if -** no error occurs, or an SQLite error code if one does. +** Attach PmaReader pReadr to file pFile (if it is not already attached to +** that file) and seek it to offset iOff within the file. Return SQLITE_OK +** if successful, or an SQLite error code if an error occurs. */ -static int vdbeSorterIterNext( - sqlite3 *db, /* Database handle (for sqlite3DbMalloc() ) */ - VdbeSorterIter *pIter /* Iterator to advance */ +static int vdbePmaReaderSeek( + SortSubtask *pTask, /* Task context */ + PmaReader *pReadr, /* Reader whose cursor is to be moved */ + SorterFile *pFile, /* Sorter file to read from */ + i64 iOff /* Offset in pFile */ ){ - int rc; /* Return Code */ + int rc = SQLITE_OK; + + assert( pReadr->pIncr==0 || pReadr->pIncr->bEof==0 ); + + if( sqlite3FaultSim(201) ) return SQLITE_IOERR_READ; + if( pReadr->aMap ){ + sqlite3OsUnfetch(pReadr->pFd, 0, pReadr->aMap); + pReadr->aMap = 0; + } + pReadr->iReadOff = iOff; + pReadr->iEof = pFile->iEof; + pReadr->pFd = pFile->pFd; + + rc = vdbeSorterMapFile(pTask, pFile, &pReadr->aMap); + if( rc==SQLITE_OK && pReadr->aMap==0 ){ + int pgsz = pTask->pSorter->pgsz; + int iBuf = pReadr->iReadOff % pgsz; + if( pReadr->aBuffer==0 ){ + pReadr->aBuffer = (u8*)sqlite3Malloc(pgsz); + if( pReadr->aBuffer==0 ) rc = SQLITE_NOMEM; + pReadr->nBuffer = pgsz; + } + if( rc==SQLITE_OK && iBuf ){ + int nRead = pgsz - iBuf; + if( (pReadr->iReadOff + nRead) > pReadr->iEof ){ + nRead = (int)(pReadr->iEof - pReadr->iReadOff); + } + rc = sqlite3OsRead( + pReadr->pFd, &pReadr->aBuffer[iBuf], nRead, pReadr->iReadOff + ); + testcase( rc!=SQLITE_OK ); + } + } + + return rc; +} + +/* +** Advance PmaReader pReadr to the next key in its PMA. Return SQLITE_OK if +** no error occurs, or an SQLite error code if one does. +*/ +static int vdbePmaReaderNext(PmaReader *pReadr){ + int rc = SQLITE_OK; /* Return Code */ u64 nRec = 0; /* Size of record in bytes */ - if( pIter->iReadOff>=pIter->iEof ){ - /* This is an EOF condition */ - vdbeSorterIterZero(db, pIter); - return SQLITE_OK; + + if( pReadr->iReadOff>=pReadr->iEof ){ + IncrMerger *pIncr = pReadr->pIncr; + int bEof = 1; + if( pIncr ){ + rc = vdbeIncrSwap(pIncr); + if( rc==SQLITE_OK && pIncr->bEof==0 ){ + rc = vdbePmaReaderSeek( + pIncr->pTask, pReadr, &pIncr->aFile[0], pIncr->iStartOff + ); + bEof = 0; + } + } + + if( bEof ){ + /* This is an EOF condition */ + vdbePmaReaderClear(pReadr); + testcase( rc!=SQLITE_OK ); + return rc; + } } - rc = vdbeSorterIterVarint(db, pIter, &nRec); if( rc==SQLITE_OK ){ - pIter->nKey = (int)nRec; - rc = vdbeSorterIterRead(db, pIter, (int)nRec, &pIter->aKey); + rc = vdbePmaReadVarint(pReadr, &nRec); + } + if( rc==SQLITE_OK ){ + pReadr->nKey = (int)nRec; + rc = vdbePmaReadBlob(pReadr, (int)nRec, &pReadr->aKey); + testcase( rc!=SQLITE_OK ); } return rc; } /* -** Initialize iterator pIter to scan through the PMA stored in file pFile +** Initialize PmaReader pReadr to scan through the PMA stored in file pFile ** starting at offset iStart and ending at offset iEof-1. This function -** leaves the iterator pointing to the first key in the PMA (or EOF if the +** leaves the PmaReader pointing to the first key in the PMA (or EOF if the ** PMA is empty). +** +** If the pnByte parameter is NULL, then it is assumed that the file +** contains a single PMA, and that that PMA omits the initial length varint. */ -static int vdbeSorterIterInit( - sqlite3 *db, /* Database handle */ - const VdbeSorter *pSorter, /* Sorter object */ +static int vdbePmaReaderInit( + SortSubtask *pTask, /* Task context */ + SorterFile *pFile, /* Sorter file to read from */ i64 iStart, /* Start offset in pFile */ - VdbeSorterIter *pIter, /* Iterator to populate */ + PmaReader *pReadr, /* PmaReader to populate */ i64 *pnByte /* IN/OUT: Increment this value by PMA size */ ){ - int rc = SQLITE_OK; - int nBuf; - - nBuf = sqlite3BtreeGetPageSize(db->aDb[0].pBt); - - assert( pSorter->iWriteOff>iStart ); - assert( pIter->aAlloc==0 ); - assert( pIter->aBuffer==0 ); - pIter->pFile = pSorter->pTemp1; - pIter->iReadOff = iStart; - pIter->nAlloc = 128; - pIter->aAlloc = (u8 *)sqlite3DbMallocRaw(db, pIter->nAlloc); - pIter->nBuffer = nBuf; - pIter->aBuffer = (u8 *)sqlite3DbMallocRaw(db, nBuf); - - if( !pIter->aBuffer ){ - rc = SQLITE_NOMEM; - }else{ - int iBuf; + int rc; - iBuf = iStart % nBuf; - if( iBuf ){ - int nRead = nBuf - iBuf; - if( (iStart + nRead) > pSorter->iWriteOff ){ - nRead = (int)(pSorter->iWriteOff - iStart); - } - rc = sqlite3OsRead( - pSorter->pTemp1, &pIter->aBuffer[iBuf], nRead, iStart - ); - } + assert( pFile->iEof>iStart ); + assert( pReadr->aAlloc==0 && pReadr->nAlloc==0 ); + assert( pReadr->aBuffer==0 ); + assert( pReadr->aMap==0 ); - if( rc==SQLITE_OK ){ - u64 nByte; /* Size of PMA in bytes */ - pIter->iEof = pSorter->iWriteOff; - rc = vdbeSorterIterVarint(db, pIter, &nByte); - pIter->iEof = pIter->iReadOff + nByte; - *pnByte += nByte; - } + rc = vdbePmaReaderSeek(pTask, pReadr, pFile, iStart); + if( rc==SQLITE_OK ){ + u64 nByte; /* Size of PMA in bytes */ + rc = vdbePmaReadVarint(pReadr, &nByte); + pReadr->iEof = pReadr->iReadOff + nByte; + *pnByte += nByte; } if( rc==SQLITE_OK ){ - rc = vdbeSorterIterNext(db, pIter); + rc = vdbePmaReaderNext(pReadr); } return rc; } @@ -370,135 +738,330 @@ static int vdbeSorterIterInit( /* ** Compare key1 (buffer pKey1, size nKey1 bytes) with key2 (buffer pKey2, -** size nKey2 bytes). Argument pKeyInfo supplies the collation functions -** used by the comparison. If an error occurs, return an SQLite error code. -** Otherwise, return SQLITE_OK and set *pRes to a negative, zero or positive -** value, depending on whether key1 is smaller, equal to or larger than key2. -** -** If the bOmitRowid argument is non-zero, assume both keys end in a rowid -** field. For the purposes of the comparison, ignore it. Also, if bOmitRowid -** is true and key1 contains even a single NULL value, it is considered to -** be less than key2. Even if key2 also contains NULL values. -** -** If pKey2 is passed a NULL pointer, then it is assumed that the pCsr->aSpace -** has been allocated and contains an unpacked record that is used as key2. -*/ -static void vdbeSorterCompare( - const VdbeCursor *pCsr, /* Cursor object (for pKeyInfo) */ - int nKeyCol, /* Num of columns. 0 means "all" */ +** size nKey2 bytes). Use (pTask->pKeyInfo) for the collation sequences +** used by the comparison. Return the result of the comparison. +** +** Before returning, object (pTask->pUnpacked) is populated with the +** unpacked version of key2. Or, if pKey2 is passed a NULL pointer, then it +** is assumed that the (pTask->pUnpacked) structure already contains the +** unpacked key to use as key2. +** +** If an OOM error is encountered, (pTask->pUnpacked->error_rc) is set +** to SQLITE_NOMEM. +*/ +static int vdbeSorterCompare( + SortSubtask *pTask, /* Subtask context (for pKeyInfo) */ const void *pKey1, int nKey1, /* Left side of comparison */ - const void *pKey2, int nKey2, /* Right side of comparison */ - int *pRes /* OUT: Result of comparison */ + const void *pKey2, int nKey2 /* Right side of comparison */ ){ - KeyInfo *pKeyInfo = pCsr->pKeyInfo; - VdbeSorter *pSorter = pCsr->pSorter; - UnpackedRecord *r2 = pSorter->pUnpacked; - int i; - + UnpackedRecord *r2 = pTask->pUnpacked; if( pKey2 ){ - sqlite3VdbeRecordUnpack(pKeyInfo, nKey2, pKey2, r2); + sqlite3VdbeRecordUnpack(pTask->pSorter->pKeyInfo, nKey2, pKey2, r2); } + return sqlite3VdbeRecordCompare(nKey1, pKey1, r2, 0); +} - if( nKeyCol ){ - r2->nField = nKeyCol; - for(i=0; i<nKeyCol; i++){ - if( r2->aMem[i].flags & MEM_Null ){ - *pRes = -1; - return; +/* +** Initialize the temporary index cursor just opened as a sorter cursor. +** +** Usually, the sorter module uses the value of (pCsr->pKeyInfo->nField) +** to determine the number of fields that should be compared from the +** records being sorted. However, if the value passed as argument nField +** is non-zero and the sorter is able to guarantee a stable sort, nField +** is used instead. This is used when sorting records for a CREATE INDEX +** statement. In this case, keys are always delivered to the sorter in +** order of the primary key, which happens to be make up the final part +** of the records being sorted. So if the sort is stable, there is never +** any reason to compare PK fields and they can be ignored for a small +** performance boost. +** +** The sorter can guarantee a stable sort when running in single-threaded +** mode, but not in multi-threaded mode. +** +** SQLITE_OK is returned if successful, or an SQLite error code otherwise. +*/ +int sqlite3VdbeSorterInit( + sqlite3 *db, /* Database connection (for malloc()) */ + int nField, /* Number of key fields in each record */ + VdbeCursor *pCsr /* Cursor that holds the new sorter */ +){ + int pgsz; /* Page size of main database */ + int i; /* Used to iterate through aTask[] */ + int mxCache; /* Cache size */ + VdbeSorter *pSorter; /* The new sorter */ + KeyInfo *pKeyInfo; /* Copy of pCsr->pKeyInfo with db==0 */ + int szKeyInfo; /* Size of pCsr->pKeyInfo in bytes */ + int sz; /* Size of pSorter in bytes */ + int rc = SQLITE_OK; +#if SQLITE_MAX_WORKER_THREADS==0 +# define nWorker 0 +#else + int nWorker; +#endif + + /* Initialize the upper limit on the number of worker threads */ +#if SQLITE_MAX_WORKER_THREADS>0 + if( sqlite3TempInMemory(db) || sqlite3GlobalConfig.bCoreMutex==0 ){ + nWorker = 0; + }else{ + nWorker = db->aLimit[SQLITE_LIMIT_WORKER_THREADS]; + } +#endif + + /* Do not allow the total number of threads (main thread + all workers) + ** to exceed the maximum merge count */ +#if SQLITE_MAX_WORKER_THREADS>=SORTER_MAX_MERGE_COUNT + if( nWorker>=SORTER_MAX_MERGE_COUNT ){ + nWorker = SORTER_MAX_MERGE_COUNT-1; + } +#endif + + assert( pCsr->pKeyInfo && pCsr->pBt==0 ); + szKeyInfo = sizeof(KeyInfo) + (pCsr->pKeyInfo->nField-1)*sizeof(CollSeq*); + sz = sizeof(VdbeSorter) + nWorker * sizeof(SortSubtask); + + pSorter = (VdbeSorter*)sqlite3DbMallocZero(db, sz + szKeyInfo); + pCsr->pSorter = pSorter; + if( pSorter==0 ){ + rc = SQLITE_NOMEM; + }else{ + pSorter->pKeyInfo = pKeyInfo = (KeyInfo*)((u8*)pSorter + sz); + memcpy(pKeyInfo, pCsr->pKeyInfo, szKeyInfo); + pKeyInfo->db = 0; + if( nField && nWorker==0 ) pKeyInfo->nField = nField; + pSorter->pgsz = pgsz = sqlite3BtreeGetPageSize(db->aDb[0].pBt); + pSorter->nTask = nWorker + 1; + pSorter->bUseThreads = (pSorter->nTask>1); + pSorter->db = db; + for(i=0; i<pSorter->nTask; i++){ + SortSubtask *pTask = &pSorter->aTask[i]; + pTask->pSorter = pSorter; + } + + if( !sqlite3TempInMemory(db) ){ + pSorter->mnPmaSize = SORTER_MIN_WORKING * pgsz; + mxCache = db->aDb[0].pSchema->cache_size; + if( mxCache<SORTER_MIN_WORKING ) mxCache = SORTER_MIN_WORKING; + pSorter->mxPmaSize = mxCache * pgsz; + + /* If the application has not configure scratch memory using + ** SQLITE_CONFIG_SCRATCH then we assume it is OK to do large memory + ** allocations. If scratch memory has been configured, then assume + ** large memory allocations should be avoided to prevent heap + ** fragmentation. + */ + if( sqlite3GlobalConfig.pScratch==0 ){ + assert( pSorter->iMemory==0 ); + pSorter->nMemory = pgsz; + pSorter->list.aMemory = (u8*)sqlite3Malloc(pgsz); + if( !pSorter->list.aMemory ) rc = SQLITE_NOMEM; } } - assert( r2->default_rc==0 ); } - *pRes = sqlite3VdbeRecordCompare(nKey1, pKey1, r2, 0); + return rc; } +#undef nWorker /* Defined at the top of this function */ /* -** This function is called to compare two iterator keys when merging -** multiple b-tree segments. Parameter iOut is the index of the aTree[] -** value to recalculate. +** Free the list of sorted records starting at pRecord. */ -static int vdbeSorterDoCompare(const VdbeCursor *pCsr, int iOut){ - VdbeSorter *pSorter = pCsr->pSorter; - int i1; - int i2; - int iRes; - VdbeSorterIter *p1; - VdbeSorterIter *p2; - - assert( iOut<pSorter->nTree && iOut>0 ); +static void vdbeSorterRecordFree(sqlite3 *db, SorterRecord *pRecord){ + SorterRecord *p; + SorterRecord *pNext; + for(p=pRecord; p; p=pNext){ + pNext = p->u.pNext; + sqlite3DbFree(db, p); + } +} - if( iOut>=(pSorter->nTree/2) ){ - i1 = (iOut - pSorter->nTree/2) * 2; - i2 = i1 + 1; - }else{ - i1 = pSorter->aTree[iOut*2]; - i2 = pSorter->aTree[iOut*2+1]; +/* +** Free all resources owned by the object indicated by argument pTask. All +** fields of *pTask are zeroed before returning. +*/ +static void vdbeSortSubtaskCleanup(sqlite3 *db, SortSubtask *pTask){ + sqlite3DbFree(db, pTask->pUnpacked); + pTask->pUnpacked = 0; +#if SQLITE_MAX_WORKER_THREADS>0 + /* pTask->list.aMemory can only be non-zero if it was handed memory + ** from the main thread. That only occurs SQLITE_MAX_WORKER_THREADS>0 */ + if( pTask->list.aMemory ){ + sqlite3_free(pTask->list.aMemory); + pTask->list.aMemory = 0; + }else +#endif + { + assert( pTask->list.aMemory==0 ); + vdbeSorterRecordFree(0, pTask->list.pList); + } + pTask->list.pList = 0; + if( pTask->file.pFd ){ + sqlite3OsCloseFree(pTask->file.pFd); + pTask->file.pFd = 0; + pTask->file.iEof = 0; + } + if( pTask->file2.pFd ){ + sqlite3OsCloseFree(pTask->file2.pFd); + pTask->file2.pFd = 0; + pTask->file2.iEof = 0; } +} - p1 = &pSorter->aIter[i1]; - p2 = &pSorter->aIter[i2]; +#ifdef SQLITE_DEBUG_SORTER_THREADS +static void vdbeSorterWorkDebug(SortSubtask *pTask, const char *zEvent){ + i64 t; + int iTask = (pTask - pTask->pSorter->aTask); + sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t); + fprintf(stderr, "%lld:%d %s\n", t, iTask, zEvent); +} +static void vdbeSorterRewindDebug(const char *zEvent){ + i64 t; + sqlite3OsCurrentTimeInt64(sqlite3_vfs_find(0), &t); + fprintf(stderr, "%lld:X %s\n", t, zEvent); +} +static void vdbeSorterPopulateDebug( + SortSubtask *pTask, + const char *zEvent +){ + i64 t; + int iTask = (pTask - pTask->pSorter->aTask); + sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t); + fprintf(stderr, "%lld:bg%d %s\n", t, iTask, zEvent); +} +static void vdbeSorterBlockDebug( + SortSubtask *pTask, + int bBlocked, + const char *zEvent +){ + if( bBlocked ){ + i64 t; + sqlite3OsCurrentTimeInt64(pTask->pSorter->db->pVfs, &t); + fprintf(stderr, "%lld:main %s\n", t, zEvent); + } +} +#else +# define vdbeSorterWorkDebug(x,y) +# define vdbeSorterRewindDebug(y) +# define vdbeSorterPopulateDebug(x,y) +# define vdbeSorterBlockDebug(x,y,z) +#endif - if( p1->pFile==0 ){ - iRes = i2; - }else if( p2->pFile==0 ){ - iRes = i1; - }else{ - int res; - assert( pCsr->pSorter->pUnpacked!=0 ); /* allocated in vdbeSorterMerge() */ - vdbeSorterCompare( - pCsr, 0, p1->aKey, p1->nKey, p2->aKey, p2->nKey, &res - ); - if( res<=0 ){ - iRes = i1; - }else{ - iRes = i2; - } +#if SQLITE_MAX_WORKER_THREADS>0 +/* +** Join thread pTask->thread. +*/ +static int vdbeSorterJoinThread(SortSubtask *pTask){ + int rc = SQLITE_OK; + if( pTask->pThread ){ +#ifdef SQLITE_DEBUG_SORTER_THREADS + int bDone = pTask->bDone; +#endif + void *pRet = SQLITE_INT_TO_PTR(SQLITE_ERROR); + vdbeSorterBlockDebug(pTask, !bDone, "enter"); + (void)sqlite3ThreadJoin(pTask->pThread, &pRet); + vdbeSorterBlockDebug(pTask, !bDone, "exit"); + rc = SQLITE_PTR_TO_INT(pRet); + assert( pTask->bDone==1 ); + pTask->bDone = 0; + pTask->pThread = 0; } + return rc; +} - pSorter->aTree[iOut] = iRes; - return SQLITE_OK; +/* +** Launch a background thread to run xTask(pIn). +*/ +static int vdbeSorterCreateThread( + SortSubtask *pTask, /* Thread will use this task object */ + void *(*xTask)(void*), /* Routine to run in a separate thread */ + void *pIn /* Argument passed into xTask() */ +){ + assert( pTask->pThread==0 && pTask->bDone==0 ); + return sqlite3ThreadCreate(&pTask->pThread, xTask, pIn); } /* -** Initialize the temporary index cursor just opened as a sorter cursor. +** Join all outstanding threads launched by SorterWrite() to create +** level-0 PMAs. */ -int sqlite3VdbeSorterInit(sqlite3 *db, VdbeCursor *pCsr){ - int pgsz; /* Page size of main database */ - int mxCache; /* Cache size */ - VdbeSorter *pSorter; /* The new sorter */ - char *d; /* Dummy */ +static int vdbeSorterJoinAll(VdbeSorter *pSorter, int rcin){ + int rc = rcin; + int i; - assert( pCsr->pKeyInfo && pCsr->pBt==0 ); - pCsr->pSorter = pSorter = sqlite3DbMallocZero(db, sizeof(VdbeSorter)); - if( pSorter==0 ){ - return SQLITE_NOMEM; + /* This function is always called by the main user thread. + ** + ** If this function is being called after SorterRewind() has been called, + ** it is possible that thread pSorter->aTask[pSorter->nTask-1].pThread + ** is currently attempt to join one of the other threads. To avoid a race + ** condition where this thread also attempts to join the same object, join + ** thread pSorter->aTask[pSorter->nTask-1].pThread first. */ + for(i=pSorter->nTask-1; i>=0; i--){ + SortSubtask *pTask = &pSorter->aTask[i]; + int rc2 = vdbeSorterJoinThread(pTask); + if( rc==SQLITE_OK ) rc = rc2; } - - pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pCsr->pKeyInfo, 0, 0, &d); - if( pSorter->pUnpacked==0 ) return SQLITE_NOMEM; - assert( pSorter->pUnpacked==(UnpackedRecord *)d ); + return rc; +} +#else +# define vdbeSorterJoinAll(x,rcin) (rcin) +# define vdbeSorterJoinThread(pTask) SQLITE_OK +#endif - if( !sqlite3TempInMemory(db) ){ - pgsz = sqlite3BtreeGetPageSize(db->aDb[0].pBt); - pSorter->mnPmaSize = SORTER_MIN_WORKING * pgsz; - mxCache = db->aDb[0].pSchema->cache_size; - if( mxCache<SORTER_MIN_WORKING ) mxCache = SORTER_MIN_WORKING; - pSorter->mxPmaSize = mxCache * pgsz; +/* +** Allocate a new MergeEngine object capable of handling up to +** nReader PmaReader inputs. +** +** nReader is automatically rounded up to the next power of two. +** nReader may not exceed SORTER_MAX_MERGE_COUNT even after rounding up. +*/ +static MergeEngine *vdbeMergeEngineNew(int nReader){ + int N = 2; /* Smallest power of two >= nReader */ + int nByte; /* Total bytes of space to allocate */ + MergeEngine *pNew; /* Pointer to allocated object to return */ + + assert( nReader<=SORTER_MAX_MERGE_COUNT ); + + while( N<nReader ) N += N; + nByte = sizeof(MergeEngine) + N * (sizeof(int) + sizeof(PmaReader)); + + pNew = sqlite3FaultSim(100) ? 0 : (MergeEngine*)sqlite3MallocZero(nByte); + if( pNew ){ + pNew->nTree = N; + pNew->pTask = 0; + pNew->aReadr = (PmaReader*)&pNew[1]; + pNew->aTree = (int*)&pNew->aReadr[N]; } + return pNew; +} - return SQLITE_OK; +/* +** Free the MergeEngine object passed as the only argument. +*/ +static void vdbeMergeEngineFree(MergeEngine *pMerger){ + int i; + if( pMerger ){ + for(i=0; i<pMerger->nTree; i++){ + vdbePmaReaderClear(&pMerger->aReadr[i]); + } + } + sqlite3_free(pMerger); } /* -** Free the list of sorted records starting at pRecord. +** Free all resources associated with the IncrMerger object indicated by +** the first argument. */ -static void vdbeSorterRecordFree(sqlite3 *db, SorterRecord *pRecord){ - SorterRecord *p; - SorterRecord *pNext; - for(p=pRecord; p; p=pNext){ - pNext = p->pNext; - sqlite3DbFree(db, p); +static void vdbeIncrFree(IncrMerger *pIncr){ + if( pIncr ){ +#if SQLITE_MAX_WORKER_THREADS>0 + if( pIncr->bUseThread ){ + vdbeSorterJoinThread(pIncr->pTask); + if( pIncr->aFile[0].pFd ) sqlite3OsCloseFree(pIncr->aFile[0].pFd); + if( pIncr->aFile[1].pFd ) sqlite3OsCloseFree(pIncr->aFile[1].pFd); + } +#endif + vdbeMergeEngineFree(pIncr->pMerger); + sqlite3_free(pIncr); } } @@ -506,29 +1069,34 @@ static void vdbeSorterRecordFree(sqlite3 *db, SorterRecord *pRecord){ ** Reset a sorting cursor back to its original empty state. */ void sqlite3VdbeSorterReset(sqlite3 *db, VdbeSorter *pSorter){ - if( pSorter->aIter ){ - int i; - for(i=0; i<pSorter->nTree; i++){ - vdbeSorterIterZero(db, &pSorter->aIter[i]); - } - sqlite3DbFree(db, pSorter->aIter); - pSorter->aIter = 0; - } - if( pSorter->pTemp1 ){ - sqlite3OsCloseFree(pSorter->pTemp1); - pSorter->pTemp1 = 0; - } - vdbeSorterRecordFree(db, pSorter->pRecord); - pSorter->pRecord = 0; - pSorter->iWriteOff = 0; - pSorter->iReadOff = 0; - pSorter->nInMemory = 0; - pSorter->nTree = 0; - pSorter->nPMA = 0; - pSorter->aTree = 0; + int i; + (void)vdbeSorterJoinAll(pSorter, SQLITE_OK); + assert( pSorter->bUseThreads || pSorter->pReader==0 ); +#if SQLITE_MAX_WORKER_THREADS>0 + if( pSorter->pReader ){ + vdbePmaReaderClear(pSorter->pReader); + sqlite3DbFree(db, pSorter->pReader); + pSorter->pReader = 0; + } +#endif + vdbeMergeEngineFree(pSorter->pMerger); + pSorter->pMerger = 0; + for(i=0; i<pSorter->nTask; i++){ + SortSubtask *pTask = &pSorter->aTask[i]; + vdbeSortSubtaskCleanup(db, pTask); + } + if( pSorter->list.aMemory==0 ){ + vdbeSorterRecordFree(0, pSorter->list.pList); + } + pSorter->list.pList = 0; + pSorter->list.szPMA = 0; + pSorter->bUsePMA = 0; + pSorter->iMemory = 0; + pSorter->mxKeysize = 0; + sqlite3DbFree(db, pSorter->pUnpacked); + pSorter->pUnpacked = 0; } - /* ** Free any cursor components allocated by sqlite3VdbeSorterXXX routines. */ @@ -536,54 +1104,110 @@ void sqlite3VdbeSorterClose(sqlite3 *db, VdbeCursor *pCsr){ VdbeSorter *pSorter = pCsr->pSorter; if( pSorter ){ sqlite3VdbeSorterReset(db, pSorter); - sqlite3DbFree(db, pSorter->pUnpacked); + sqlite3_free(pSorter->list.aMemory); sqlite3DbFree(db, pSorter); pCsr->pSorter = 0; } } +#if SQLITE_MAX_MMAP_SIZE>0 +/* +** The first argument is a file-handle open on a temporary file. The file +** is guaranteed to be nByte bytes or smaller in size. This function +** attempts to extend the file to nByte bytes in size and to ensure that +** the VFS has memory mapped it. +** +** Whether or not the file does end up memory mapped of course depends on +** the specific VFS implementation. +*/ +static void vdbeSorterExtendFile(sqlite3 *db, sqlite3_file *pFd, i64 nByte){ + if( nByte<=(i64)(db->nMaxSorterMmap) ){ + int rc = sqlite3OsTruncate(pFd, nByte); + if( rc==SQLITE_OK ){ + void *p = 0; + sqlite3OsFetch(pFd, 0, (int)nByte, &p); + sqlite3OsUnfetch(pFd, 0, p); + } + } +} +#else +# define vdbeSorterExtendFile(x,y,z) +#endif + /* ** Allocate space for a file-handle and open a temporary file. If successful, -** set *ppFile to point to the malloc'd file-handle and return SQLITE_OK. -** Otherwise, set *ppFile to 0 and return an SQLite error code. +** set *ppFd to point to the malloc'd file-handle and return SQLITE_OK. +** Otherwise, set *ppFd to 0 and return an SQLite error code. */ -static int vdbeSorterOpenTempFile(sqlite3 *db, sqlite3_file **ppFile){ - int dummy; - return sqlite3OsOpenMalloc(db->pVfs, 0, ppFile, +static int vdbeSorterOpenTempFile( + sqlite3 *db, /* Database handle doing sort */ + i64 nExtend, /* Attempt to extend file to this size */ + sqlite3_file **ppFd +){ + int rc; + rc = sqlite3OsOpenMalloc(db->pVfs, 0, ppFd, SQLITE_OPEN_TEMP_JOURNAL | SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | - SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE, &dummy + SQLITE_OPEN_EXCLUSIVE | SQLITE_OPEN_DELETEONCLOSE, &rc ); + if( rc==SQLITE_OK ){ + i64 max = SQLITE_MAX_MMAP_SIZE; + sqlite3OsFileControlHint(*ppFd, SQLITE_FCNTL_MMAP_SIZE, (void*)&max); + if( nExtend>0 ){ + vdbeSorterExtendFile(db, *ppFd, nExtend); + } + } + return rc; +} + +/* +** If it has not already been allocated, allocate the UnpackedRecord +** structure at pTask->pUnpacked. Return SQLITE_OK if successful (or +** if no allocation was required), or SQLITE_NOMEM otherwise. +*/ +static int vdbeSortAllocUnpacked(SortSubtask *pTask){ + if( pTask->pUnpacked==0 ){ + char *pFree; + pTask->pUnpacked = sqlite3VdbeAllocUnpackedRecord( + pTask->pSorter->pKeyInfo, 0, 0, &pFree + ); + assert( pTask->pUnpacked==(UnpackedRecord*)pFree ); + if( pFree==0 ) return SQLITE_NOMEM; + pTask->pUnpacked->nField = pTask->pSorter->pKeyInfo->nField; + pTask->pUnpacked->errCode = 0; + } + return SQLITE_OK; } + /* ** Merge the two sorted lists p1 and p2 into a single list. ** Set *ppOut to the head of the new list. */ static void vdbeSorterMerge( - const VdbeCursor *pCsr, /* For pKeyInfo */ + SortSubtask *pTask, /* Calling thread context */ SorterRecord *p1, /* First list to merge */ SorterRecord *p2, /* Second list to merge */ SorterRecord **ppOut /* OUT: Head of merged list */ ){ SorterRecord *pFinal = 0; SorterRecord **pp = &pFinal; - void *pVal2 = p2 ? p2->pVal : 0; + void *pVal2 = p2 ? SRVAL(p2) : 0; while( p1 && p2 ){ int res; - vdbeSorterCompare(pCsr, 0, p1->pVal, p1->nVal, pVal2, p2->nVal, &res); + res = vdbeSorterCompare(pTask, SRVAL(p1), p1->nVal, pVal2, p2->nVal); if( res<=0 ){ *pp = p1; - pp = &p1->pNext; - p1 = p1->pNext; + pp = &p1->u.pNext; + p1 = p1->u.pNext; pVal2 = 0; }else{ *pp = p2; - pp = &p2->pNext; - p2 = p2->pNext; + pp = &p2->u.pNext; + p2 = p2->u.pNext; if( p2==0 ) break; - pVal2 = p2->pVal; + pVal2 = SRVAL(p2); } } *pp = p1 ? p1 : p2; @@ -591,27 +1215,41 @@ static void vdbeSorterMerge( } /* -** Sort the linked list of records headed at pCsr->pRecord. Return SQLITE_OK -** if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if an error -** occurs. +** Sort the linked list of records headed at pTask->pList. Return +** SQLITE_OK if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if +** an error occurs. */ -static int vdbeSorterSort(const VdbeCursor *pCsr){ +static int vdbeSorterSort(SortSubtask *pTask, SorterList *pList){ int i; SorterRecord **aSlot; SorterRecord *p; - VdbeSorter *pSorter = pCsr->pSorter; + int rc; + + rc = vdbeSortAllocUnpacked(pTask); + if( rc!=SQLITE_OK ) return rc; aSlot = (SorterRecord **)sqlite3MallocZero(64 * sizeof(SorterRecord *)); if( !aSlot ){ return SQLITE_NOMEM; } - p = pSorter->pRecord; + p = pList->pList; while( p ){ - SorterRecord *pNext = p->pNext; - p->pNext = 0; + SorterRecord *pNext; + if( pList->aMemory ){ + if( (u8*)p==pList->aMemory ){ + pNext = 0; + }else{ + assert( p->u.iNext<sqlite3MallocSize(pList->aMemory) ); + pNext = (SorterRecord*)&pList->aMemory[p->u.iNext]; + } + }else{ + pNext = p->u.pNext; + } + + p->u.pNext = 0; for(i=0; aSlot[i]; i++){ - vdbeSorterMerge(pCsr, p, aSlot[i], &p); + vdbeSorterMerge(pTask, p, aSlot[i], &p); aSlot[i] = 0; } aSlot[i] = p; @@ -620,42 +1258,43 @@ static int vdbeSorterSort(const VdbeCursor *pCsr){ p = 0; for(i=0; i<64; i++){ - vdbeSorterMerge(pCsr, p, aSlot[i], &p); + vdbeSorterMerge(pTask, p, aSlot[i], &p); } - pSorter->pRecord = p; + pList->pList = p; sqlite3_free(aSlot); - return SQLITE_OK; + assert( pTask->pUnpacked->errCode==SQLITE_OK + || pTask->pUnpacked->errCode==SQLITE_NOMEM + ); + return pTask->pUnpacked->errCode; } /* -** Initialize a file-writer object. +** Initialize a PMA-writer object. */ -static void fileWriterInit( - sqlite3 *db, /* Database (for malloc) */ - sqlite3_file *pFile, /* File to write to */ - FileWriter *p, /* Object to populate */ - i64 iStart /* Offset of pFile to begin writing at */ +static void vdbePmaWriterInit( + sqlite3_file *pFd, /* File handle to write to */ + PmaWriter *p, /* Object to populate */ + int nBuf, /* Buffer size */ + i64 iStart /* Offset of pFd to begin writing at */ ){ - int nBuf = sqlite3BtreeGetPageSize(db->aDb[0].pBt); - - memset(p, 0, sizeof(FileWriter)); - p->aBuffer = (u8 *)sqlite3DbMallocRaw(db, nBuf); + memset(p, 0, sizeof(PmaWriter)); + p->aBuffer = (u8*)sqlite3Malloc(nBuf); if( !p->aBuffer ){ p->eFWErr = SQLITE_NOMEM; }else{ p->iBufEnd = p->iBufStart = (iStart % nBuf); p->iWriteOff = iStart - p->iBufStart; p->nBuffer = nBuf; - p->pFile = pFile; + p->pFd = pFd; } } /* -** Write nData bytes of data to the file-write object. Return SQLITE_OK +** Write nData bytes of data to the PMA. Return SQLITE_OK ** if successful, or an SQLite error code if an error occurs. */ -static void fileWriterWrite(FileWriter *p, u8 *pData, int nData){ +static void vdbePmaWriteBlob(PmaWriter *p, u8 *pData, int nData){ int nRem = nData; while( nRem>0 && p->eFWErr==0 ){ int nCopy = nRem; @@ -666,7 +1305,7 @@ static void fileWriterWrite(FileWriter *p, u8 *pData, int nData){ memcpy(&p->aBuffer[p->iBufEnd], &pData[nData-nRem], nCopy); p->iBufEnd += nCopy; if( p->iBufEnd==p->nBuffer ){ - p->eFWErr = sqlite3OsWrite(p->pFile, + p->eFWErr = sqlite3OsWrite(p->pFd, &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart, p->iWriteOff + p->iBufStart ); @@ -680,43 +1319,44 @@ static void fileWriterWrite(FileWriter *p, u8 *pData, int nData){ } /* -** Flush any buffered data to disk and clean up the file-writer object. -** The results of using the file-writer after this call are undefined. +** Flush any buffered data to disk and clean up the PMA-writer object. +** The results of using the PMA-writer after this call are undefined. ** Return SQLITE_OK if flushing the buffered data succeeds or is not ** required. Otherwise, return an SQLite error code. ** ** Before returning, set *piEof to the offset immediately following the ** last byte written to the file. */ -static int fileWriterFinish(sqlite3 *db, FileWriter *p, i64 *piEof){ +static int vdbePmaWriterFinish(PmaWriter *p, i64 *piEof){ int rc; if( p->eFWErr==0 && ALWAYS(p->aBuffer) && p->iBufEnd>p->iBufStart ){ - p->eFWErr = sqlite3OsWrite(p->pFile, + p->eFWErr = sqlite3OsWrite(p->pFd, &p->aBuffer[p->iBufStart], p->iBufEnd - p->iBufStart, p->iWriteOff + p->iBufStart ); } *piEof = (p->iWriteOff + p->iBufEnd); - sqlite3DbFree(db, p->aBuffer); + sqlite3_free(p->aBuffer); rc = p->eFWErr; - memset(p, 0, sizeof(FileWriter)); + memset(p, 0, sizeof(PmaWriter)); return rc; } /* -** Write value iVal encoded as a varint to the file-write object. Return +** Write value iVal encoded as a varint to the PMA. Return ** SQLITE_OK if successful, or an SQLite error code if an error occurs. */ -static void fileWriterWriteVarint(FileWriter *p, u64 iVal){ +static void vdbePmaWriteVarint(PmaWriter *p, u64 iVal){ int nByte; u8 aByte[10]; nByte = sqlite3PutVarint(aByte, iVal); - fileWriterWrite(p, aByte, nByte); + vdbePmaWriteBlob(p, aByte, nByte); } /* -** Write the current contents of the in-memory linked-list to a PMA. Return -** SQLITE_OK if successful, or an SQLite error code otherwise. +** Write the current contents of in-memory linked-list pList to a level-0 +** PMA in the temp file belonging to sub-task pTask. Return SQLITE_OK if +** successful, or an SQLite error code otherwise. ** ** The format of a PMA is: ** @@ -727,76 +1367,246 @@ static void fileWriterWriteVarint(FileWriter *p, u64 iVal){ ** Each record consists of a varint followed by a blob of data (the ** key). The varint is the number of bytes in the blob of data. */ -static int vdbeSorterListToPMA(sqlite3 *db, const VdbeCursor *pCsr){ +static int vdbeSorterListToPMA(SortSubtask *pTask, SorterList *pList){ + sqlite3 *db = pTask->pSorter->db; int rc = SQLITE_OK; /* Return code */ - VdbeSorter *pSorter = pCsr->pSorter; - FileWriter writer; + PmaWriter writer; /* Object used to write to the file */ - memset(&writer, 0, sizeof(FileWriter)); +#ifdef SQLITE_DEBUG + /* Set iSz to the expected size of file pTask->file after writing the PMA. + ** This is used by an assert() statement at the end of this function. */ + i64 iSz = pList->szPMA + sqlite3VarintLen(pList->szPMA) + pTask->file.iEof; +#endif - if( pSorter->nInMemory==0 ){ - assert( pSorter->pRecord==0 ); - return rc; + vdbeSorterWorkDebug(pTask, "enter"); + memset(&writer, 0, sizeof(PmaWriter)); + assert( pList->szPMA>0 ); + + /* If the first temporary PMA file has not been opened, open it now. */ + if( pTask->file.pFd==0 ){ + rc = vdbeSorterOpenTempFile(db, 0, &pTask->file.pFd); + assert( rc!=SQLITE_OK || pTask->file.pFd ); + assert( pTask->file.iEof==0 ); + assert( pTask->nPMA==0 ); } - rc = vdbeSorterSort(pCsr); + /* Try to get the file to memory map */ + if( rc==SQLITE_OK ){ + vdbeSorterExtendFile(db, pTask->file.pFd, pTask->file.iEof+pList->szPMA+9); + } - /* If the first temporary PMA file has not been opened, open it now. */ - if( rc==SQLITE_OK && pSorter->pTemp1==0 ){ - rc = vdbeSorterOpenTempFile(db, &pSorter->pTemp1); - assert( rc!=SQLITE_OK || pSorter->pTemp1 ); - assert( pSorter->iWriteOff==0 ); - assert( pSorter->nPMA==0 ); + /* Sort the list */ + if( rc==SQLITE_OK ){ + rc = vdbeSorterSort(pTask, pList); } if( rc==SQLITE_OK ){ SorterRecord *p; SorterRecord *pNext = 0; - fileWriterInit(db, pSorter->pTemp1, &writer, pSorter->iWriteOff); - pSorter->nPMA++; - fileWriterWriteVarint(&writer, pSorter->nInMemory); - for(p=pSorter->pRecord; p; p=pNext){ - pNext = p->pNext; - fileWriterWriteVarint(&writer, p->nVal); - fileWriterWrite(&writer, p->pVal, p->nVal); - sqlite3DbFree(db, p); + vdbePmaWriterInit(pTask->file.pFd, &writer, pTask->pSorter->pgsz, + pTask->file.iEof); + pTask->nPMA++; + vdbePmaWriteVarint(&writer, pList->szPMA); + for(p=pList->pList; p; p=pNext){ + pNext = p->u.pNext; + vdbePmaWriteVarint(&writer, p->nVal); + vdbePmaWriteBlob(&writer, SRVAL(p), p->nVal); + if( pList->aMemory==0 ) sqlite3_free(p); + } + pList->pList = p; + rc = vdbePmaWriterFinish(&writer, &pTask->file.iEof); + } + + vdbeSorterWorkDebug(pTask, "exit"); + assert( rc!=SQLITE_OK || pList->pList==0 ); + assert( rc!=SQLITE_OK || pTask->file.iEof==iSz ); + return rc; +} + +/* +** Advance the MergeEngine to its next entry. +** Set *pbEof to true there is no next entry because +** the MergeEngine has reached the end of all its inputs. +** +** Return SQLITE_OK if successful or an error code if an error occurs. +*/ +static int vdbeMergeEngineStep( + MergeEngine *pMerger, /* The merge engine to advance to the next row */ + int *pbEof /* Set TRUE at EOF. Set false for more content */ +){ + int rc; + int iPrev = pMerger->aTree[1];/* Index of PmaReader to advance */ + SortSubtask *pTask = pMerger->pTask; + + /* Advance the current PmaReader */ + rc = vdbePmaReaderNext(&pMerger->aReadr[iPrev]); + + /* Update contents of aTree[] */ + if( rc==SQLITE_OK ){ + int i; /* Index of aTree[] to recalculate */ + PmaReader *pReadr1; /* First PmaReader to compare */ + PmaReader *pReadr2; /* Second PmaReader to compare */ + u8 *pKey2; /* To pReadr2->aKey, or 0 if record cached */ + + /* Find the first two PmaReaders to compare. The one that was just + ** advanced (iPrev) and the one next to it in the array. */ + pReadr1 = &pMerger->aReadr[(iPrev & 0xFFFE)]; + pReadr2 = &pMerger->aReadr[(iPrev | 0x0001)]; + pKey2 = pReadr2->aKey; + + for(i=(pMerger->nTree+iPrev)/2; i>0; i=i/2){ + /* Compare pReadr1 and pReadr2. Store the result in variable iRes. */ + int iRes; + if( pReadr1->pFd==0 ){ + iRes = +1; + }else if( pReadr2->pFd==0 ){ + iRes = -1; + }else{ + iRes = vdbeSorterCompare(pTask, + pReadr1->aKey, pReadr1->nKey, pKey2, pReadr2->nKey + ); + } + + /* If pReadr1 contained the smaller value, set aTree[i] to its index. + ** Then set pReadr2 to the next PmaReader to compare to pReadr1. In this + ** case there is no cache of pReadr2 in pTask->pUnpacked, so set + ** pKey2 to point to the record belonging to pReadr2. + ** + ** Alternatively, if pReadr2 contains the smaller of the two values, + ** set aTree[i] to its index and update pReadr1. If vdbeSorterCompare() + ** was actually called above, then pTask->pUnpacked now contains + ** a value equivalent to pReadr2. So set pKey2 to NULL to prevent + ** vdbeSorterCompare() from decoding pReadr2 again. + ** + ** If the two values were equal, then the value from the oldest + ** PMA should be considered smaller. The VdbeSorter.aReadr[] array + ** is sorted from oldest to newest, so pReadr1 contains older values + ** than pReadr2 iff (pReadr1<pReadr2). */ + if( iRes<0 || (iRes==0 && pReadr1<pReadr2) ){ + pMerger->aTree[i] = (int)(pReadr1 - pMerger->aReadr); + pReadr2 = &pMerger->aReadr[ pMerger->aTree[i ^ 0x0001] ]; + pKey2 = pReadr2->aKey; + }else{ + if( pReadr1->pFd ) pKey2 = 0; + pMerger->aTree[i] = (int)(pReadr2 - pMerger->aReadr); + pReadr1 = &pMerger->aReadr[ pMerger->aTree[i ^ 0x0001] ]; + } + } + *pbEof = (pMerger->aReadr[pMerger->aTree[1]].pFd==0); + } + + return (rc==SQLITE_OK ? pTask->pUnpacked->errCode : rc); +} + +#if SQLITE_MAX_WORKER_THREADS>0 +/* +** The main routine for background threads that write level-0 PMAs. +*/ +static void *vdbeSorterFlushThread(void *pCtx){ + SortSubtask *pTask = (SortSubtask*)pCtx; + int rc; /* Return code */ + assert( pTask->bDone==0 ); + rc = vdbeSorterListToPMA(pTask, &pTask->list); + pTask->bDone = 1; + return SQLITE_INT_TO_PTR(rc); +} +#endif /* SQLITE_MAX_WORKER_THREADS>0 */ + +/* +** Flush the current contents of VdbeSorter.list to a new PMA, possibly +** using a background thread. +*/ +static int vdbeSorterFlushPMA(VdbeSorter *pSorter){ +#if SQLITE_MAX_WORKER_THREADS==0 + pSorter->bUsePMA = 1; + return vdbeSorterListToPMA(&pSorter->aTask[0], &pSorter->list); +#else + int rc = SQLITE_OK; + int i; + SortSubtask *pTask = 0; /* Thread context used to create new PMA */ + int nWorker = (pSorter->nTask-1); + + /* Set the flag to indicate that at least one PMA has been written. + ** Or will be, anyhow. */ + pSorter->bUsePMA = 1; + + /* Select a sub-task to sort and flush the current list of in-memory + ** records to disk. If the sorter is running in multi-threaded mode, + ** round-robin between the first (pSorter->nTask-1) tasks. Except, if + ** the background thread from a sub-tasks previous turn is still running, + ** skip it. If the first (pSorter->nTask-1) sub-tasks are all still busy, + ** fall back to using the final sub-task. The first (pSorter->nTask-1) + ** sub-tasks are prefered as they use background threads - the final + ** sub-task uses the main thread. */ + for(i=0; i<nWorker; i++){ + int iTest = (pSorter->iPrev + i + 1) % nWorker; + pTask = &pSorter->aTask[iTest]; + if( pTask->bDone ){ + rc = vdbeSorterJoinThread(pTask); + } + if( rc!=SQLITE_OK || pTask->pThread==0 ) break; + } + + if( rc==SQLITE_OK ){ + if( i==nWorker ){ + /* Use the foreground thread for this operation */ + rc = vdbeSorterListToPMA(&pSorter->aTask[nWorker], &pSorter->list); + }else{ + /* Launch a background thread for this operation */ + u8 *aMem = pTask->list.aMemory; + void *pCtx = (void*)pTask; + + assert( pTask->pThread==0 && pTask->bDone==0 ); + assert( pTask->list.pList==0 ); + assert( pTask->list.aMemory==0 || pSorter->list.aMemory!=0 ); + + pSorter->iPrev = (u8)(pTask - pSorter->aTask); + pTask->list = pSorter->list; + pSorter->list.pList = 0; + pSorter->list.szPMA = 0; + if( aMem ){ + pSorter->list.aMemory = aMem; + pSorter->nMemory = sqlite3MallocSize(aMem); + }else if( pSorter->list.aMemory ){ + pSorter->list.aMemory = sqlite3Malloc(pSorter->nMemory); + if( !pSorter->list.aMemory ) return SQLITE_NOMEM; + } + + rc = vdbeSorterCreateThread(pTask, vdbeSorterFlushThread, pCtx); } - pSorter->pRecord = p; - rc = fileWriterFinish(db, &writer, &pSorter->iWriteOff); } return rc; +#endif /* SQLITE_MAX_WORKER_THREADS!=0 */ } /* ** Add a record to the sorter. */ int sqlite3VdbeSorterWrite( - sqlite3 *db, /* Database handle */ - const VdbeCursor *pCsr, /* Sorter cursor */ + const VdbeCursor *pCsr, /* Sorter cursor */ Mem *pVal /* Memory cell containing record */ ){ VdbeSorter *pSorter = pCsr->pSorter; int rc = SQLITE_OK; /* Return Code */ SorterRecord *pNew; /* New list element */ - assert( pSorter ); - pSorter->nInMemory += sqlite3VarintLen(pVal->n) + pVal->n; + int bFlush; /* True to flush contents of memory to PMA */ + int nReq; /* Bytes of memory required */ + int nPMA; /* Bytes of PMA space required */ - pNew = (SorterRecord *)sqlite3DbMallocRaw(db, pVal->n + sizeof(SorterRecord)); - if( pNew==0 ){ - rc = SQLITE_NOMEM; - }else{ - pNew->pVal = (void *)&pNew[1]; - memcpy(pNew->pVal, pVal->z, pVal->n); - pNew->nVal = pVal->n; - pNew->pNext = pSorter->pRecord; - pSorter->pRecord = pNew; - } + assert( pSorter ); - /* See if the contents of the sorter should now be written out. They - ** are written out when either of the following are true: + /* Figure out whether or not the current contents of memory should be + ** flushed to a PMA before continuing. If so, do so. + ** + ** If using the single large allocation mode (pSorter->aMemory!=0), then + ** flush the contents of memory to a new PMA if (a) at least one value is + ** already in memory and (b) the new value will not fit in memory. + ** + ** Or, if using separate allocations for each record, flush the contents + ** of memory to a PMA if either of the following are true: ** ** * The total memory allocated for the in-memory list is greater ** than (page-size * cache-size), or @@ -804,161 +1614,778 @@ int sqlite3VdbeSorterWrite( ** * The total memory allocated for the in-memory list is greater ** than (page-size * 10) and sqlite3HeapNearlyFull() returns true. */ - if( rc==SQLITE_OK && pSorter->mxPmaSize>0 && ( - (pSorter->nInMemory>pSorter->mxPmaSize) - || (pSorter->nInMemory>pSorter->mnPmaSize && sqlite3HeapNearlyFull()) - )){ -#ifdef SQLITE_DEBUG - i64 nExpect = pSorter->iWriteOff - + sqlite3VarintLen(pSorter->nInMemory) - + pSorter->nInMemory; + nReq = pVal->n + sizeof(SorterRecord); + nPMA = pVal->n + sqlite3VarintLen(pVal->n); + if( pSorter->mxPmaSize ){ + if( pSorter->list.aMemory ){ + bFlush = pSorter->iMemory && (pSorter->iMemory+nReq) > pSorter->mxPmaSize; + }else{ + bFlush = ( + (pSorter->list.szPMA > pSorter->mxPmaSize) + || (pSorter->list.szPMA > pSorter->mnPmaSize && sqlite3HeapNearlyFull()) + ); + } + if( bFlush ){ + rc = vdbeSorterFlushPMA(pSorter); + pSorter->list.szPMA = 0; + pSorter->iMemory = 0; + assert( rc!=SQLITE_OK || pSorter->list.pList==0 ); + } + } + + pSorter->list.szPMA += nPMA; + if( nPMA>pSorter->mxKeysize ){ + pSorter->mxKeysize = nPMA; + } + + if( pSorter->list.aMemory ){ + int nMin = pSorter->iMemory + nReq; + + if( nMin>pSorter->nMemory ){ + u8 *aNew; + int nNew = pSorter->nMemory * 2; + while( nNew < nMin ) nNew = nNew*2; + if( nNew > pSorter->mxPmaSize ) nNew = pSorter->mxPmaSize; + if( nNew < nMin ) nNew = nMin; + + aNew = sqlite3Realloc(pSorter->list.aMemory, nNew); + if( !aNew ) return SQLITE_NOMEM; + pSorter->list.pList = (SorterRecord*)( + aNew + ((u8*)pSorter->list.pList - pSorter->list.aMemory) + ); + pSorter->list.aMemory = aNew; + pSorter->nMemory = nNew; + } + + pNew = (SorterRecord*)&pSorter->list.aMemory[pSorter->iMemory]; + pSorter->iMemory += ROUND8(nReq); + pNew->u.iNext = (int)((u8*)(pSorter->list.pList) - pSorter->list.aMemory); + }else{ + pNew = (SorterRecord *)sqlite3Malloc(nReq); + if( pNew==0 ){ + return SQLITE_NOMEM; + } + pNew->u.pNext = pSorter->list.pList; + } + + memcpy(SRVAL(pNew), pVal->z, pVal->n); + pNew->nVal = pVal->n; + pSorter->list.pList = pNew; + + return rc; +} + +/* +** Read keys from pIncr->pMerger and populate pIncr->aFile[1]. The format +** of the data stored in aFile[1] is the same as that used by regular PMAs, +** except that the number-of-bytes varint is omitted from the start. +*/ +static int vdbeIncrPopulate(IncrMerger *pIncr){ + int rc = SQLITE_OK; + int rc2; + i64 iStart = pIncr->iStartOff; + SorterFile *pOut = &pIncr->aFile[1]; + SortSubtask *pTask = pIncr->pTask; + MergeEngine *pMerger = pIncr->pMerger; + PmaWriter writer; + assert( pIncr->bEof==0 ); + + vdbeSorterPopulateDebug(pTask, "enter"); + + vdbePmaWriterInit(pOut->pFd, &writer, pTask->pSorter->pgsz, iStart); + while( rc==SQLITE_OK ){ + int dummy; + PmaReader *pReader = &pMerger->aReadr[ pMerger->aTree[1] ]; + int nKey = pReader->nKey; + i64 iEof = writer.iWriteOff + writer.iBufEnd; + + /* Check if the output file is full or if the input has been exhausted. + ** In either case exit the loop. */ + if( pReader->pFd==0 ) break; + if( (iEof + nKey + sqlite3VarintLen(nKey))>(iStart + pIncr->mxSz) ) break; + + /* Write the next key to the output. */ + vdbePmaWriteVarint(&writer, nKey); + vdbePmaWriteBlob(&writer, pReader->aKey, nKey); + assert( pIncr->pMerger->pTask==pTask ); + rc = vdbeMergeEngineStep(pIncr->pMerger, &dummy); + } + + rc2 = vdbePmaWriterFinish(&writer, &pOut->iEof); + if( rc==SQLITE_OK ) rc = rc2; + vdbeSorterPopulateDebug(pTask, "exit"); + return rc; +} + +#if SQLITE_MAX_WORKER_THREADS>0 +/* +** The main routine for background threads that populate aFile[1] of +** multi-threaded IncrMerger objects. +*/ +static void *vdbeIncrPopulateThread(void *pCtx){ + IncrMerger *pIncr = (IncrMerger*)pCtx; + void *pRet = SQLITE_INT_TO_PTR( vdbeIncrPopulate(pIncr) ); + pIncr->pTask->bDone = 1; + return pRet; +} + +/* +** Launch a background thread to populate aFile[1] of pIncr. +*/ +static int vdbeIncrBgPopulate(IncrMerger *pIncr){ + void *p = (void*)pIncr; + assert( pIncr->bUseThread ); + return vdbeSorterCreateThread(pIncr->pTask, vdbeIncrPopulateThread, p); +} #endif - rc = vdbeSorterListToPMA(db, pCsr); - pSorter->nInMemory = 0; - assert( rc!=SQLITE_OK || (nExpect==pSorter->iWriteOff) ); + +/* +** This function is called when the PmaReader corresponding to pIncr has +** finished reading the contents of aFile[0]. Its purpose is to "refill" +** aFile[0] such that the PmaReader should start rereading it from the +** beginning. +** +** For single-threaded objects, this is accomplished by literally reading +** keys from pIncr->pMerger and repopulating aFile[0]. +** +** For multi-threaded objects, all that is required is to wait until the +** background thread is finished (if it is not already) and then swap +** aFile[0] and aFile[1] in place. If the contents of pMerger have not +** been exhausted, this function also launches a new background thread +** to populate the new aFile[1]. +** +** SQLITE_OK is returned on success, or an SQLite error code otherwise. +*/ +static int vdbeIncrSwap(IncrMerger *pIncr){ + int rc = SQLITE_OK; + +#if SQLITE_MAX_WORKER_THREADS>0 + if( pIncr->bUseThread ){ + rc = vdbeSorterJoinThread(pIncr->pTask); + + if( rc==SQLITE_OK ){ + SorterFile f0 = pIncr->aFile[0]; + pIncr->aFile[0] = pIncr->aFile[1]; + pIncr->aFile[1] = f0; + } + + if( rc==SQLITE_OK ){ + if( pIncr->aFile[0].iEof==pIncr->iStartOff ){ + pIncr->bEof = 1; + }else{ + rc = vdbeIncrBgPopulate(pIncr); + } + } + }else +#endif + { + rc = vdbeIncrPopulate(pIncr); + pIncr->aFile[0] = pIncr->aFile[1]; + if( pIncr->aFile[0].iEof==pIncr->iStartOff ){ + pIncr->bEof = 1; + } } return rc; } /* -** Helper function for sqlite3VdbeSorterRewind(). +** Allocate and return a new IncrMerger object to read data from pMerger. +** +** If an OOM condition is encountered, return NULL. In this case free the +** pMerger argument before returning. */ -static int vdbeSorterInitMerge( - sqlite3 *db, /* Database handle */ - const VdbeCursor *pCsr, /* Cursor handle for this sorter */ - i64 *pnByte /* Sum of bytes in all opened PMAs */ +static int vdbeIncrMergerNew( + SortSubtask *pTask, /* The thread that will be using the new IncrMerger */ + MergeEngine *pMerger, /* The MergeEngine that the IncrMerger will control */ + IncrMerger **ppOut /* Write the new IncrMerger here */ +){ + int rc = SQLITE_OK; + IncrMerger *pIncr = *ppOut = (IncrMerger*) + (sqlite3FaultSim(100) ? 0 : sqlite3MallocZero(sizeof(*pIncr))); + if( pIncr ){ + pIncr->pMerger = pMerger; + pIncr->pTask = pTask; + pIncr->mxSz = MAX(pTask->pSorter->mxKeysize+9,pTask->pSorter->mxPmaSize/2); + pTask->file2.iEof += pIncr->mxSz; + }else{ + vdbeMergeEngineFree(pMerger); + rc = SQLITE_NOMEM; + } + return rc; +} + +#if SQLITE_MAX_WORKER_THREADS>0 +/* +** Set the "use-threads" flag on object pIncr. +*/ +static void vdbeIncrMergerSetThreads(IncrMerger *pIncr){ + pIncr->bUseThread = 1; + pIncr->pTask->file2.iEof -= pIncr->mxSz; +} +#endif /* SQLITE_MAX_WORKER_THREADS>0 */ + + + +/* +** Recompute pMerger->aTree[iOut] by comparing the next keys on the +** two PmaReaders that feed that entry. Neither of the PmaReaders +** are advanced. This routine merely does the comparison. +*/ +static void vdbeMergeEngineCompare( + MergeEngine *pMerger, /* Merge engine containing PmaReaders to compare */ + int iOut /* Store the result in pMerger->aTree[iOut] */ +){ + int i1; + int i2; + int iRes; + PmaReader *p1; + PmaReader *p2; + + assert( iOut<pMerger->nTree && iOut>0 ); + + if( iOut>=(pMerger->nTree/2) ){ + i1 = (iOut - pMerger->nTree/2) * 2; + i2 = i1 + 1; + }else{ + i1 = pMerger->aTree[iOut*2]; + i2 = pMerger->aTree[iOut*2+1]; + } + + p1 = &pMerger->aReadr[i1]; + p2 = &pMerger->aReadr[i2]; + + if( p1->pFd==0 ){ + iRes = i2; + }else if( p2->pFd==0 ){ + iRes = i1; + }else{ + int res; + assert( pMerger->pTask->pUnpacked!=0 ); /* from vdbeSortSubtaskMain() */ + res = vdbeSorterCompare( + pMerger->pTask, p1->aKey, p1->nKey, p2->aKey, p2->nKey + ); + if( res<=0 ){ + iRes = i1; + }else{ + iRes = i2; + } + } + + pMerger->aTree[iOut] = iRes; +} + +/* +** Allowed values for the eMode parameter to vdbeMergeEngineInit() +** and vdbePmaReaderIncrMergeInit(). +** +** Only INCRINIT_NORMAL is valid in single-threaded builds (when +** SQLITE_MAX_WORKER_THREADS==0). The other values are only used +** when there exists one or more separate worker threads. +*/ +#define INCRINIT_NORMAL 0 +#define INCRINIT_TASK 1 +#define INCRINIT_ROOT 2 + +/* Forward reference. +** The vdbeIncrMergeInit() and vdbePmaReaderIncrMergeInit() routines call each +** other (when building a merge tree). +*/ +static int vdbePmaReaderIncrMergeInit(PmaReader *pReadr, int eMode); + +/* +** Initialize the MergeEngine object passed as the second argument. Once this +** function returns, the first key of merged data may be read from the +** MergeEngine object in the usual fashion. +** +** If argument eMode is INCRINIT_ROOT, then it is assumed that any IncrMerge +** objects attached to the PmaReader objects that the merger reads from have +** already been populated, but that they have not yet populated aFile[0] and +** set the PmaReader objects up to read from it. In this case all that is +** required is to call vdbePmaReaderNext() on each PmaReader to point it at +** its first key. +** +** Otherwise, if eMode is any value other than INCRINIT_ROOT, then use +** vdbePmaReaderIncrMergeInit() to initialize each PmaReader that feeds data +** to pMerger. +** +** SQLITE_OK is returned if successful, or an SQLite error code otherwise. +*/ +static int vdbeMergeEngineInit( + SortSubtask *pTask, /* Thread that will run pMerger */ + MergeEngine *pMerger, /* MergeEngine to initialize */ + int eMode /* One of the INCRINIT_XXX constants */ ){ - VdbeSorter *pSorter = pCsr->pSorter; int rc = SQLITE_OK; /* Return code */ - int i; /* Used to iterator through aIter[] */ - i64 nByte = 0; /* Total bytes in all opened PMAs */ + int i; /* For looping over PmaReader objects */ + int nTree = pMerger->nTree; + + /* eMode is always INCRINIT_NORMAL in single-threaded mode */ + assert( SQLITE_MAX_WORKER_THREADS>0 || eMode==INCRINIT_NORMAL ); + + /* Verify that the MergeEngine is assigned to a single thread */ + assert( pMerger->pTask==0 ); + pMerger->pTask = pTask; + + for(i=0; i<nTree; i++){ + if( SQLITE_MAX_WORKER_THREADS>0 && eMode==INCRINIT_ROOT ){ + /* PmaReaders should be normally initialized in order, as if they are + ** reading from the same temp file this makes for more linear file IO. + ** However, in the INCRINIT_ROOT case, if PmaReader aReadr[nTask-1] is + ** in use it will block the vdbePmaReaderNext() call while it uses + ** the main thread to fill its buffer. So calling PmaReaderNext() + ** on this PmaReader before any of the multi-threaded PmaReaders takes + ** better advantage of multi-processor hardware. */ + rc = vdbePmaReaderNext(&pMerger->aReadr[nTree-i-1]); + }else{ + rc = vdbePmaReaderIncrMergeInit(&pMerger->aReadr[i], INCRINIT_NORMAL); + } + if( rc!=SQLITE_OK ) return rc; + } - /* Initialize the iterators. */ - for(i=0; i<SORTER_MAX_MERGE_COUNT; i++){ - VdbeSorterIter *pIter = &pSorter->aIter[i]; - rc = vdbeSorterIterInit(db, pSorter, pSorter->iReadOff, pIter, &nByte); - pSorter->iReadOff = pIter->iEof; - assert( rc!=SQLITE_OK || pSorter->iReadOff<=pSorter->iWriteOff ); - if( rc!=SQLITE_OK || pSorter->iReadOff>=pSorter->iWriteOff ) break; + for(i=pMerger->nTree-1; i>0; i--){ + vdbeMergeEngineCompare(pMerger, i); } + return pTask->pUnpacked->errCode; +} - /* Initialize the aTree[] array. */ - for(i=pSorter->nTree-1; rc==SQLITE_OK && i>0; i--){ - rc = vdbeSorterDoCompare(pCsr, i); +/* +** Initialize the IncrMerge field of a PmaReader. +** +** If the PmaReader passed as the first argument is not an incremental-reader +** (if pReadr->pIncr==0), then this function is a no-op. Otherwise, it serves +** to open and/or initialize the temp file related fields of the IncrMerge +** object at (pReadr->pIncr). +** +** If argument eMode is set to INCRINIT_NORMAL, then all PmaReaders +** in the sub-tree headed by pReadr are also initialized. Data is then loaded +** into the buffers belonging to pReadr and it is set to +** point to the first key in its range. +** +** If argument eMode is set to INCRINIT_TASK, then pReadr is guaranteed +** to be a multi-threaded PmaReader and this function is being called in a +** background thread. In this case all PmaReaders in the sub-tree are +** initialized as for INCRINIT_NORMAL and the aFile[1] buffer belonging to +** pReadr is populated. However, pReadr itself is not set up to point +** to its first key. A call to vdbePmaReaderNext() is still required to do +** that. +** +** The reason this function does not call vdbePmaReaderNext() immediately +** in the INCRINIT_TASK case is that vdbePmaReaderNext() assumes that it has +** to block on thread (pTask->thread) before accessing aFile[1]. But, since +** this entire function is being run by thread (pTask->thread), that will +** lead to the current background thread attempting to join itself. +** +** Finally, if argument eMode is set to INCRINIT_ROOT, it may be assumed +** that pReadr->pIncr is a multi-threaded IncrMerge objects, and that all +** child-trees have already been initialized using IncrInit(INCRINIT_TASK). +** In this case vdbePmaReaderNext() is called on all child PmaReaders and +** the current PmaReader set to point to the first key in its range. +** +** SQLITE_OK is returned if successful, or an SQLite error code otherwise. +*/ +static int vdbePmaReaderIncrMergeInit(PmaReader *pReadr, int eMode){ + int rc = SQLITE_OK; + IncrMerger *pIncr = pReadr->pIncr; + + /* eMode is always INCRINIT_NORMAL in single-threaded mode */ + assert( SQLITE_MAX_WORKER_THREADS>0 || eMode==INCRINIT_NORMAL ); + + if( pIncr ){ + SortSubtask *pTask = pIncr->pTask; + sqlite3 *db = pTask->pSorter->db; + + rc = vdbeMergeEngineInit(pTask, pIncr->pMerger, eMode); + + /* Set up the required files for pIncr. A multi-theaded IncrMerge object + ** requires two temp files to itself, whereas a single-threaded object + ** only requires a region of pTask->file2. */ + if( rc==SQLITE_OK ){ + int mxSz = pIncr->mxSz; +#if SQLITE_MAX_WORKER_THREADS>0 + if( pIncr->bUseThread ){ + rc = vdbeSorterOpenTempFile(db, mxSz, &pIncr->aFile[0].pFd); + if( rc==SQLITE_OK ){ + rc = vdbeSorterOpenTempFile(db, mxSz, &pIncr->aFile[1].pFd); + } + }else +#endif + /*if( !pIncr->bUseThread )*/{ + if( pTask->file2.pFd==0 ){ + assert( pTask->file2.iEof>0 ); + rc = vdbeSorterOpenTempFile(db, pTask->file2.iEof, &pTask->file2.pFd); + pTask->file2.iEof = 0; + } + if( rc==SQLITE_OK ){ + pIncr->aFile[1].pFd = pTask->file2.pFd; + pIncr->iStartOff = pTask->file2.iEof; + pTask->file2.iEof += mxSz; + } + } + } + +#if SQLITE_MAX_WORKER_THREADS>0 + if( rc==SQLITE_OK && pIncr->bUseThread ){ + /* Use the current thread to populate aFile[1], even though this + ** PmaReader is multi-threaded. The reason being that this function + ** is already running in background thread pIncr->pTask->thread. */ + assert( eMode==INCRINIT_ROOT || eMode==INCRINIT_TASK ); + rc = vdbeIncrPopulate(pIncr); + } +#endif + + if( rc==SQLITE_OK + && (SQLITE_MAX_WORKER_THREADS==0 || eMode!=INCRINIT_TASK) + ){ + rc = vdbePmaReaderNext(pReadr); + } + } + return rc; +} + +#if SQLITE_MAX_WORKER_THREADS>0 +/* +** The main routine for vdbePmaReaderIncrMergeInit() operations run in +** background threads. +*/ +static void *vdbePmaReaderBgInit(void *pCtx){ + PmaReader *pReader = (PmaReader*)pCtx; + void *pRet = SQLITE_INT_TO_PTR( + vdbePmaReaderIncrMergeInit(pReader,INCRINIT_TASK) + ); + pReader->pIncr->pTask->bDone = 1; + return pRet; +} + +/* +** Use a background thread to invoke vdbePmaReaderIncrMergeInit(INCRINIT_TASK) +** on the the PmaReader object passed as the first argument. +** +** This call will initialize the various fields of the pReadr->pIncr +** structure and, if it is a multi-threaded IncrMerger, launch a +** background thread to populate aFile[1]. +*/ +static int vdbePmaReaderBgIncrInit(PmaReader *pReadr){ + void *pCtx = (void*)pReadr; + return vdbeSorterCreateThread(pReadr->pIncr->pTask, vdbePmaReaderBgInit, pCtx); +} +#endif + +/* +** Allocate a new MergeEngine object to merge the contents of nPMA level-0 +** PMAs from pTask->file. If no error occurs, set *ppOut to point to +** the new object and return SQLITE_OK. Or, if an error does occur, set *ppOut +** to NULL and return an SQLite error code. +** +** When this function is called, *piOffset is set to the offset of the +** first PMA to read from pTask->file. Assuming no error occurs, it is +** set to the offset immediately following the last byte of the last +** PMA before returning. If an error does occur, then the final value of +** *piOffset is undefined. +*/ +static int vdbeMergeEngineLevel0( + SortSubtask *pTask, /* Sorter task to read from */ + int nPMA, /* Number of PMAs to read */ + i64 *piOffset, /* IN/OUT: Readr offset in pTask->file */ + MergeEngine **ppOut /* OUT: New merge-engine */ +){ + MergeEngine *pNew; /* Merge engine to return */ + i64 iOff = *piOffset; + int i; + int rc = SQLITE_OK; + + *ppOut = pNew = vdbeMergeEngineNew(nPMA); + if( pNew==0 ) rc = SQLITE_NOMEM; + + for(i=0; i<nPMA && rc==SQLITE_OK; i++){ + i64 nDummy; + PmaReader *pReadr = &pNew->aReadr[i]; + rc = vdbePmaReaderInit(pTask, &pTask->file, iOff, pReadr, &nDummy); + iOff = pReadr->iEof; } - *pnByte = nByte; + if( rc!=SQLITE_OK ){ + vdbeMergeEngineFree(pNew); + *ppOut = 0; + } + *piOffset = iOff; return rc; } /* -** Once the sorter has been populated, this function is called to prepare -** for iterating through its contents in sorted order. +** Return the depth of a tree comprising nPMA PMAs, assuming a fanout of +** SORTER_MAX_MERGE_COUNT. The returned value does not include leaf nodes. +** +** i.e. +** +** nPMA<=16 -> TreeDepth() == 0 +** nPMA<=256 -> TreeDepth() == 1 +** nPMA<=65536 -> TreeDepth() == 2 */ -int sqlite3VdbeSorterRewind(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){ - VdbeSorter *pSorter = pCsr->pSorter; - int rc; /* Return code */ - sqlite3_file *pTemp2 = 0; /* Second temp file to use */ - i64 iWrite2 = 0; /* Write offset for pTemp2 */ - int nIter; /* Number of iterators used */ - int nByte; /* Bytes of space required for aIter/aTree */ - int N = 2; /* Power of 2 >= nIter */ +static int vdbeSorterTreeDepth(int nPMA){ + int nDepth = 0; + i64 nDiv = SORTER_MAX_MERGE_COUNT; + while( nDiv < (i64)nPMA ){ + nDiv = nDiv * SORTER_MAX_MERGE_COUNT; + nDepth++; + } + return nDepth; +} - assert( pSorter ); +/* +** pRoot is the root of an incremental merge-tree with depth nDepth (according +** to vdbeSorterTreeDepth()). pLeaf is the iSeq'th leaf to be added to the +** tree, counting from zero. This function adds pLeaf to the tree. +** +** If successful, SQLITE_OK is returned. If an error occurs, an SQLite error +** code is returned and pLeaf is freed. +*/ +static int vdbeSorterAddToTree( + SortSubtask *pTask, /* Task context */ + int nDepth, /* Depth of tree according to TreeDepth() */ + int iSeq, /* Sequence number of leaf within tree */ + MergeEngine *pRoot, /* Root of tree */ + MergeEngine *pLeaf /* Leaf to add to tree */ +){ + int rc = SQLITE_OK; + int nDiv = 1; + int i; + MergeEngine *p = pRoot; + IncrMerger *pIncr; - /* If no data has been written to disk, then do not do so now. Instead, - ** sort the VdbeSorter.pRecord list. The vdbe layer will read data directly - ** from the in-memory list. */ - if( pSorter->nPMA==0 ){ - *pbEof = !pSorter->pRecord; - assert( pSorter->aTree==0 ); - return vdbeSorterSort(pCsr); + rc = vdbeIncrMergerNew(pTask, pLeaf, &pIncr); + + for(i=1; i<nDepth; i++){ + nDiv = nDiv * SORTER_MAX_MERGE_COUNT; } - /* Write the current in-memory list to a PMA. */ - rc = vdbeSorterListToPMA(db, pCsr); - if( rc!=SQLITE_OK ) return rc; + for(i=1; i<nDepth && rc==SQLITE_OK; i++){ + int iIter = (iSeq / nDiv) % SORTER_MAX_MERGE_COUNT; + PmaReader *pReadr = &p->aReadr[iIter]; - /* Allocate space for aIter[] and aTree[]. */ - nIter = pSorter->nPMA; - if( nIter>SORTER_MAX_MERGE_COUNT ) nIter = SORTER_MAX_MERGE_COUNT; - assert( nIter>0 ); - while( N<nIter ) N += N; - nByte = N * (sizeof(int) + sizeof(VdbeSorterIter)); - pSorter->aIter = (VdbeSorterIter *)sqlite3DbMallocZero(db, nByte); - if( !pSorter->aIter ) return SQLITE_NOMEM; - pSorter->aTree = (int *)&pSorter->aIter[N]; - pSorter->nTree = N; - - do { - int iNew; /* Index of new, merged, PMA */ - - for(iNew=0; - rc==SQLITE_OK && iNew*SORTER_MAX_MERGE_COUNT<pSorter->nPMA; - iNew++ - ){ - int rc2; /* Return code from fileWriterFinish() */ - FileWriter writer; /* Object used to write to disk */ - i64 nWrite; /* Number of bytes in new PMA */ + if( pReadr->pIncr==0 ){ + MergeEngine *pNew = vdbeMergeEngineNew(SORTER_MAX_MERGE_COUNT); + if( pNew==0 ){ + rc = SQLITE_NOMEM; + }else{ + rc = vdbeIncrMergerNew(pTask, pNew, &pReadr->pIncr); + } + } + if( rc==SQLITE_OK ){ + p = pReadr->pIncr->pMerger; + nDiv = nDiv / SORTER_MAX_MERGE_COUNT; + } + } + + if( rc==SQLITE_OK ){ + p->aReadr[iSeq % SORTER_MAX_MERGE_COUNT].pIncr = pIncr; + }else{ + vdbeIncrFree(pIncr); + } + return rc; +} - memset(&writer, 0, sizeof(FileWriter)); +/* +** This function is called as part of a SorterRewind() operation on a sorter +** that has already written two or more level-0 PMAs to one or more temp +** files. It builds a tree of MergeEngine/IncrMerger/PmaReader objects that +** can be used to incrementally merge all PMAs on disk. +** +** If successful, SQLITE_OK is returned and *ppOut set to point to the +** MergeEngine object at the root of the tree before returning. Or, if an +** error occurs, an SQLite error code is returned and the final value +** of *ppOut is undefined. +*/ +static int vdbeSorterMergeTreeBuild( + VdbeSorter *pSorter, /* The VDBE cursor that implements the sort */ + MergeEngine **ppOut /* Write the MergeEngine here */ +){ + MergeEngine *pMain = 0; + int rc = SQLITE_OK; + int iTask; + +#if SQLITE_MAX_WORKER_THREADS>0 + /* If the sorter uses more than one task, then create the top-level + ** MergeEngine here. This MergeEngine will read data from exactly + ** one PmaReader per sub-task. */ + assert( pSorter->bUseThreads || pSorter->nTask==1 ); + if( pSorter->nTask>1 ){ + pMain = vdbeMergeEngineNew(pSorter->nTask); + if( pMain==0 ) rc = SQLITE_NOMEM; + } +#endif - /* If there are SORTER_MAX_MERGE_COUNT or less PMAs in file pTemp1, - ** initialize an iterator for each of them and break out of the loop. - ** These iterators will be incrementally merged as the VDBE layer calls - ** sqlite3VdbeSorterNext(). - ** - ** Otherwise, if pTemp1 contains more than SORTER_MAX_MERGE_COUNT PMAs, - ** initialize interators for SORTER_MAX_MERGE_COUNT of them. These PMAs - ** are merged into a single PMA that is written to file pTemp2. - */ - rc = vdbeSorterInitMerge(db, pCsr, &nWrite); - assert( rc!=SQLITE_OK || pSorter->aIter[ pSorter->aTree[1] ].pFile ); - if( rc!=SQLITE_OK || pSorter->nPMA<=SORTER_MAX_MERGE_COUNT ){ - break; + for(iTask=0; rc==SQLITE_OK && iTask<pSorter->nTask; iTask++){ + SortSubtask *pTask = &pSorter->aTask[iTask]; + assert( pTask->nPMA>0 || SQLITE_MAX_WORKER_THREADS>0 ); + if( SQLITE_MAX_WORKER_THREADS==0 || pTask->nPMA ){ + MergeEngine *pRoot = 0; /* Root node of tree for this task */ + int nDepth = vdbeSorterTreeDepth(pTask->nPMA); + i64 iReadOff = 0; + + if( pTask->nPMA<=SORTER_MAX_MERGE_COUNT ){ + rc = vdbeMergeEngineLevel0(pTask, pTask->nPMA, &iReadOff, &pRoot); + }else{ + int i; + int iSeq = 0; + pRoot = vdbeMergeEngineNew(SORTER_MAX_MERGE_COUNT); + if( pRoot==0 ) rc = SQLITE_NOMEM; + for(i=0; i<pTask->nPMA && rc==SQLITE_OK; i += SORTER_MAX_MERGE_COUNT){ + MergeEngine *pMerger = 0; /* New level-0 PMA merger */ + int nReader; /* Number of level-0 PMAs to merge */ + + nReader = MIN(pTask->nPMA - i, SORTER_MAX_MERGE_COUNT); + rc = vdbeMergeEngineLevel0(pTask, nReader, &iReadOff, &pMerger); + if( rc==SQLITE_OK ){ + rc = vdbeSorterAddToTree(pTask, nDepth, iSeq++, pRoot, pMerger); + } + } } - /* Open the second temp file, if it is not already open. */ - if( pTemp2==0 ){ - assert( iWrite2==0 ); - rc = vdbeSorterOpenTempFile(db, &pTemp2); + if( rc==SQLITE_OK ){ +#if SQLITE_MAX_WORKER_THREADS>0 + if( pMain!=0 ){ + rc = vdbeIncrMergerNew(pTask, pRoot, &pMain->aReadr[iTask].pIncr); + }else +#endif + { + assert( pMain==0 ); + pMain = pRoot; + } + }else{ + vdbeMergeEngineFree(pRoot); } + } + } + + if( rc!=SQLITE_OK ){ + vdbeMergeEngineFree(pMain); + pMain = 0; + } + *ppOut = pMain; + return rc; +} + +/* +** This function is called as part of an sqlite3VdbeSorterRewind() operation +** on a sorter that has written two or more PMAs to temporary files. It sets +** up either VdbeSorter.pMerger (for single threaded sorters) or pReader +** (for multi-threaded sorters) so that it can be used to iterate through +** all records stored in the sorter. +** +** SQLITE_OK is returned if successful, or an SQLite error code otherwise. +*/ +static int vdbeSorterSetupMerge(VdbeSorter *pSorter){ + int rc; /* Return code */ + SortSubtask *pTask0 = &pSorter->aTask[0]; + MergeEngine *pMain = 0; +#if SQLITE_MAX_WORKER_THREADS + sqlite3 *db = pTask0->pSorter->db; +#endif + rc = vdbeSorterMergeTreeBuild(pSorter, &pMain); + if( rc==SQLITE_OK ){ +#if SQLITE_MAX_WORKER_THREADS + assert( pSorter->bUseThreads==0 || pSorter->nTask>1 ); + if( pSorter->bUseThreads ){ + int iTask; + PmaReader *pReadr; + SortSubtask *pLast = &pSorter->aTask[pSorter->nTask-1]; + rc = vdbeSortAllocUnpacked(pLast); if( rc==SQLITE_OK ){ - int bEof = 0; - fileWriterInit(db, pTemp2, &writer, iWrite2); - fileWriterWriteVarint(&writer, nWrite); - while( rc==SQLITE_OK && bEof==0 ){ - VdbeSorterIter *pIter = &pSorter->aIter[ pSorter->aTree[1] ]; - assert( pIter->pFile ); - - fileWriterWriteVarint(&writer, pIter->nKey); - fileWriterWrite(&writer, pIter->aKey, pIter->nKey); - rc = sqlite3VdbeSorterNext(db, pCsr, &bEof); + pReadr = (PmaReader*)sqlite3DbMallocZero(db, sizeof(PmaReader)); + pSorter->pReader = pReadr; + if( pReadr==0 ) rc = SQLITE_NOMEM; + } + if( rc==SQLITE_OK ){ + rc = vdbeIncrMergerNew(pLast, pMain, &pReadr->pIncr); + if( rc==SQLITE_OK ){ + vdbeIncrMergerSetThreads(pReadr->pIncr); + for(iTask=0; iTask<(pSorter->nTask-1); iTask++){ + IncrMerger *pIncr; + if( (pIncr = pMain->aReadr[iTask].pIncr) ){ + vdbeIncrMergerSetThreads(pIncr); + assert( pIncr->pTask!=pLast ); + } + } + for(iTask=0; rc==SQLITE_OK && iTask<pSorter->nTask; iTask++){ + PmaReader *p = &pMain->aReadr[iTask]; + assert( p->pIncr==0 || p->pIncr->pTask==&pSorter->aTask[iTask] ); + if( p->pIncr ){ + if( iTask==pSorter->nTask-1 ){ + rc = vdbePmaReaderIncrMergeInit(p, INCRINIT_TASK); + }else{ + rc = vdbePmaReaderBgIncrInit(p); + } + } + } } - rc2 = fileWriterFinish(db, &writer, &iWrite2); - if( rc==SQLITE_OK ) rc = rc2; + pMain = 0; + } + if( rc==SQLITE_OK ){ + rc = vdbePmaReaderIncrMergeInit(pReadr, INCRINIT_ROOT); } + }else +#endif + { + rc = vdbeMergeEngineInit(pTask0, pMain, INCRINIT_NORMAL); + pSorter->pMerger = pMain; + pMain = 0; } + } + + if( rc!=SQLITE_OK ){ + vdbeMergeEngineFree(pMain); + } + return rc; +} - if( pSorter->nPMA<=SORTER_MAX_MERGE_COUNT ){ - break; + +/* +** Once the sorter has been populated by calls to sqlite3VdbeSorterWrite, +** this function is called to prepare for iterating through the records +** in sorted order. +*/ +int sqlite3VdbeSorterRewind(const VdbeCursor *pCsr, int *pbEof){ + VdbeSorter *pSorter = pCsr->pSorter; + int rc = SQLITE_OK; /* Return code */ + + assert( pSorter ); + + /* If no data has been written to disk, then do not do so now. Instead, + ** sort the VdbeSorter.pRecord list. The vdbe layer will read data directly + ** from the in-memory list. */ + if( pSorter->bUsePMA==0 ){ + if( pSorter->list.pList ){ + *pbEof = 0; + rc = vdbeSorterSort(&pSorter->aTask[0], &pSorter->list); }else{ - sqlite3_file *pTmp = pSorter->pTemp1; - pSorter->nPMA = iNew; - pSorter->pTemp1 = pTemp2; - pTemp2 = pTmp; - pSorter->iWriteOff = iWrite2; - pSorter->iReadOff = 0; - iWrite2 = 0; + *pbEof = 1; } - }while( rc==SQLITE_OK ); + return rc; + } + + /* Write the current in-memory list to a PMA. When the VdbeSorterWrite() + ** function flushes the contents of memory to disk, it immediately always + ** creates a new list consisting of a single key immediately afterwards. + ** So the list is never empty at this point. */ + assert( pSorter->list.pList ); + rc = vdbeSorterFlushPMA(pSorter); + + /* Join all threads */ + rc = vdbeSorterJoinAll(pSorter, rc); - if( pTemp2 ){ - sqlite3OsCloseFree(pTemp2); + vdbeSorterRewindDebug("rewind"); + + /* Assuming no errors have occurred, set up a merger structure to + ** incrementally read and merge all remaining PMAs. */ + assert( pSorter->pReader==0 ); + if( rc==SQLITE_OK ){ + rc = vdbeSorterSetupMerge(pSorter); + *pbEof = 0; } - *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0); + + vdbeSorterRewindDebug("rewinddone"); return rc; } @@ -969,63 +2396,27 @@ int sqlite3VdbeSorterNext(sqlite3 *db, const VdbeCursor *pCsr, int *pbEof){ VdbeSorter *pSorter = pCsr->pSorter; int rc; /* Return code */ - if( pSorter->aTree ){ - int iPrev = pSorter->aTree[1];/* Index of iterator to advance */ - rc = vdbeSorterIterNext(db, &pSorter->aIter[iPrev]); - if( rc==SQLITE_OK ){ - int i; /* Index of aTree[] to recalculate */ - VdbeSorterIter *pIter1; /* First iterator to compare */ - VdbeSorterIter *pIter2; /* Second iterator to compare */ - u8 *pKey2; /* To pIter2->aKey, or 0 if record cached */ - - /* Find the first two iterators to compare. The one that was just - ** advanced (iPrev) and the one next to it in the array. */ - pIter1 = &pSorter->aIter[(iPrev & 0xFFFE)]; - pIter2 = &pSorter->aIter[(iPrev | 0x0001)]; - pKey2 = pIter2->aKey; - - for(i=(pSorter->nTree+iPrev)/2; i>0; i=i/2){ - /* Compare pIter1 and pIter2. Store the result in variable iRes. */ - int iRes; - if( pIter1->pFile==0 ){ - iRes = +1; - }else if( pIter2->pFile==0 ){ - iRes = -1; - }else{ - vdbeSorterCompare(pCsr, 0, - pIter1->aKey, pIter1->nKey, pKey2, pIter2->nKey, &iRes - ); - } - - /* If pIter1 contained the smaller value, set aTree[i] to its index. - ** Then set pIter2 to the next iterator to compare to pIter1. In this - ** case there is no cache of pIter2 in pSorter->pUnpacked, so set - ** pKey2 to point to the record belonging to pIter2. - ** - ** Alternatively, if pIter2 contains the smaller of the two values, - ** set aTree[i] to its index and update pIter1. If vdbeSorterCompare() - ** was actually called above, then pSorter->pUnpacked now contains - ** a value equivalent to pIter2. So set pKey2 to NULL to prevent - ** vdbeSorterCompare() from decoding pIter2 again. */ - if( iRes<=0 ){ - pSorter->aTree[i] = (int)(pIter1 - pSorter->aIter); - pIter2 = &pSorter->aIter[ pSorter->aTree[i ^ 0x0001] ]; - pKey2 = pIter2->aKey; - }else{ - if( pIter1->pFile ) pKey2 = 0; - pSorter->aTree[i] = (int)(pIter2 - pSorter->aIter); - pIter1 = &pSorter->aIter[ pSorter->aTree[i ^ 0x0001] ]; - } - - } - *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0); + assert( pSorter->bUsePMA || (pSorter->pReader==0 && pSorter->pMerger==0) ); + if( pSorter->bUsePMA ){ + assert( pSorter->pReader==0 || pSorter->pMerger==0 ); + assert( pSorter->bUseThreads==0 || pSorter->pReader ); + assert( pSorter->bUseThreads==1 || pSorter->pMerger ); +#if SQLITE_MAX_WORKER_THREADS>0 + if( pSorter->bUseThreads ){ + rc = vdbePmaReaderNext(pSorter->pReader); + *pbEof = (pSorter->pReader->pFd==0); + }else +#endif + /*if( !pSorter->bUseThreads )*/ { + assert( pSorter->pMerger->pTask==(&pSorter->aTask[0]) ); + rc = vdbeMergeEngineStep(pSorter->pMerger, pbEof); } }else{ - SorterRecord *pFree = pSorter->pRecord; - pSorter->pRecord = pFree->pNext; - pFree->pNext = 0; - vdbeSorterRecordFree(db, pFree); - *pbEof = !pSorter->pRecord; + SorterRecord *pFree = pSorter->list.pList; + pSorter->list.pList = pFree->u.pNext; + pFree->u.pNext = 0; + if( pSorter->list.aMemory==0 ) vdbeSorterRecordFree(db, pFree); + *pbEof = !pSorter->list.pList; rc = SQLITE_OK; } return rc; @@ -1040,14 +2431,21 @@ static void *vdbeSorterRowkey( int *pnKey /* OUT: Size of current key in bytes */ ){ void *pKey; - if( pSorter->aTree ){ - VdbeSorterIter *pIter; - pIter = &pSorter->aIter[ pSorter->aTree[1] ]; - *pnKey = pIter->nKey; - pKey = pIter->aKey; + if( pSorter->bUsePMA ){ + PmaReader *pReader; +#if SQLITE_MAX_WORKER_THREADS>0 + if( pSorter->bUseThreads ){ + pReader = pSorter->pReader; + }else +#endif + /*if( !pSorter->bUseThreads )*/{ + pReader = &pSorter->pMerger->aReadr[pSorter->pMerger->aTree[1]]; + } + *pnKey = pReader->nKey; + pKey = pReader->aKey; }else{ - *pnKey = pSorter->pRecord->nVal; - pKey = pSorter->pRecord->pVal; + *pnKey = pSorter->list.pList->nVal; + pKey = SRVAL(pSorter->list.pList); } return pKey; } @@ -1075,21 +2473,47 @@ int sqlite3VdbeSorterRowkey(const VdbeCursor *pCsr, Mem *pOut){ ** passed as the first argument currently points to. For the purposes of ** the comparison, ignore the rowid field at the end of each record. ** +** If the sorter cursor key contains any NULL values, consider it to be +** less than pVal. Even if pVal also contains NULL values. +** ** If an error occurs, return an SQLite error code (i.e. SQLITE_NOMEM). ** Otherwise, set *pRes to a negative, zero or positive value if the ** key in pVal is smaller than, equal to or larger than the current sorter ** key. +** +** This routine forms the core of the OP_SorterCompare opcode, which in +** turn is used to verify uniqueness when constructing a UNIQUE INDEX. */ int sqlite3VdbeSorterCompare( const VdbeCursor *pCsr, /* Sorter cursor */ Mem *pVal, /* Value to compare to current sorter key */ - int nKeyCol, /* Only compare this many fields */ + int nKeyCol, /* Compare this many columns */ int *pRes /* OUT: Result of comparison */ ){ VdbeSorter *pSorter = pCsr->pSorter; + UnpackedRecord *r2 = pSorter->pUnpacked; + KeyInfo *pKeyInfo = pCsr->pKeyInfo; + int i; void *pKey; int nKey; /* Sorter key to compare pVal with */ + if( r2==0 ){ + char *p; + r2 = pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pKeyInfo,0,0,&p); + assert( pSorter->pUnpacked==(UnpackedRecord*)p ); + if( r2==0 ) return SQLITE_NOMEM; + r2->nField = nKeyCol; + } + assert( r2->nField==nKeyCol ); + pKey = vdbeSorterRowkey(pSorter, &nKey); - vdbeSorterCompare(pCsr, nKeyCol, pVal->z, pVal->n, pKey, nKey, pRes); + sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, r2); + for(i=0; i<nKeyCol; i++){ + if( r2->aMem[i].flags & MEM_Null ){ + *pRes = -1; + return SQLITE_OK; + } + } + + *pRes = sqlite3VdbeRecordCompare(pVal->n, pVal->z, r2, 0); return SQLITE_OK; } |