diff options
Diffstat (limited to 'src/analyze.c')
| -rw-r--r-- | src/analyze.c | 503 |
1 files changed, 337 insertions, 166 deletions
diff --git a/src/analyze.c b/src/analyze.c index 17c1de83a..7ccddfb11 100644 --- a/src/analyze.c +++ b/src/analyze.c @@ -10,6 +10,95 @@ ** ************************************************************************* ** This file contains code associated with the ANALYZE command. +** +** The ANALYZE command gather statistics about the content of tables +** and indices. These statistics are made available to the query planner +** to help it make better decisions about how to perform queries. +** +** The following system tables are or have been supported: +** +** CREATE TABLE sqlite_stat1(tbl, idx, stat); +** CREATE TABLE sqlite_stat2(tbl, idx, sampleno, sample); +** CREATE TABLE sqlite_stat3(tbl, idx, nLt, nEq, sample); +** +** Additional tables might be added in future releases of SQLite. +** The sqlite_stat2 table is not created or used unless the SQLite version +** is between 3.6.18 and 3.7.7, inclusive, and unless SQLite is compiled +** with SQLITE_ENABLE_STAT2. The sqlite_stat2 table is deprecated. +** The sqlite_stat2 table is superceded by sqlite_stat3, which is only +** created and used by SQLite versions after 2011-08-09 with +** SQLITE_ENABLE_STAT3 defined. The fucntionality of sqlite_stat3 +** is a superset of sqlite_stat2. +** +** Format of sqlite_stat1: +** +** There is normally one row per index, with the index identified by the +** name in the idx column. The tbl column is the name of the table to +** which the index belongs. In each such row, the stat column will be +** a string consisting of a list of integers. The first integer in this +** list is the number of rows in the index and in the table. The second +** integer is the average number of rows in the index that have the same +** value in the first column of the index. The third integer is the average +** number of rows in the index that have the same value for the first two +** columns. The N-th integer (for N>1) is the average number of rows in +** the index which have the same value for the first N-1 columns. For +** a K-column index, there will be K+1 integers in the stat column. If +** the index is unique, then the last integer will be 1. +** +** The list of integers in the stat column can optionally be followed +** by the keyword "unordered". The "unordered" keyword, if it is present, +** must be separated from the last integer by a single space. If the +** "unordered" keyword is present, then the query planner assumes that +** the index is unordered and will not use the index for a range query. +** +** If the sqlite_stat1.idx column is NULL, then the sqlite_stat1.stat +** column contains a single integer which is the (estimated) number of +** rows in the table identified by sqlite_stat1.tbl. +** +** Format of sqlite_stat2: +** +** The sqlite_stat2 is only created and is only used if SQLite is compiled +** with SQLITE_ENABLE_STAT2 and if the SQLite version number is between +** 3.6.18 and 3.7.7. The "stat2" table contains additional information +** about the distribution of keys within an index. The index is identified by +** the "idx" column and the "tbl" column is the name of the table to which +** the index belongs. There are usually 10 rows in the sqlite_stat2 +** table for each index. +** +** The sqlite_stat2 entires for an index that have sampleno between 0 and 9 +** inclusive are samples of the left-most key value in the index taken at +** evenly spaced points along the index. Let the number of samples be S +** (10 in the standard build) and let C be the number of rows in the index. +** Then the sampled rows are given by: +** +** rownumber = (i*C*2 + C)/(S*2) +** +** For i between 0 and S-1. Conceptually, the index space is divided into +** S uniform buckets and the samples are the middle row from each bucket. +** +** The format for sqlite_stat2 is recorded here for legacy reference. This +** version of SQLite does not support sqlite_stat2. It neither reads nor +** writes the sqlite_stat2 table. This version of SQLite only supports +** sqlite_stat3. +** +** Format for sqlite_stat3: +** +** The sqlite_stat3 is an enhancement to sqlite_stat2. A new name is +** used to avoid compatibility problems. +** +** The format of the sqlite_stat3 table is similar to the format for +** the sqlite_stat2 table, with the following changes: (1) +** The sampleno column is removed. (2) Every sample has nEq and nLt +** columns which hold the approximate number of keys in the table that +** exactly match the sample, and which are less than the sample, +** respectively. (3) The number of samples can very from one table +** to the next; the sample count does not have to be exactly 10 as +** it is with sqlite_stat2. (4) The samples do not have to be evenly spaced. +** +** The ANALYZE command will typically generate sqlite_stat3 tables +** that contain between 10 and 40 samples which are distributed across +** the key space, though not uniformly, and which include samples with +** largest possible nEq values. */ #ifndef SQLITE_OMIT_ANALYZE #include "sqliteInt.h" @@ -42,8 +131,14 @@ static void openStatTable( const char *zCols; } aTable[] = { { "sqlite_stat1", "tbl,idx,stat" }, -#ifdef SQLITE_ENABLE_STAT2 - { "sqlite_stat2", "tbl,idx,sampleno,sample" }, +#ifdef SQLITE_ENABLE_STAT3 + { "sqlite_stat3", "tbl,idx,neq,nlt,sample" }, +#endif + }; + static const char *azToDrop[] = { + "sqlite_stat2", +#ifndef SQLITE_ENABLE_STAT3 + "sqlite_stat3", #endif }; @@ -59,6 +154,17 @@ static void openStatTable( assert( sqlite3VdbeDb(v)==db ); pDb = &db->aDb[iDb]; + /* Drop all statistics tables that this version of SQLite does not + ** understand. + */ + for(i=0; i<ArraySize(azToDrop); i++){ + Table *pTab = sqlite3FindTable(db, azToDrop[i], pDb->zName); + if( pTab ) sqlite3CodeDropTable(pParse, pTab, iDb, 0); + } + + /* Create new statistic tables if they do not exist, or clear them + ** if they do already exist. + */ for(i=0; i<ArraySize(aTable); i++){ const char *zTab = aTable[i].zName; Table *pStat; @@ -89,7 +195,7 @@ static void openStatTable( } } - /* Open the sqlite_stat[12] tables for writing. */ + /* Open the sqlite_stat[13] tables for writing. */ for(i=0; i<ArraySize(aTable); i++){ sqlite3VdbeAddOp3(v, OP_OpenWrite, iStatCur+i, aRoot[i], iDb); sqlite3VdbeChangeP4(v, -1, (char *)3, P4_INT32); @@ -98,6 +204,13 @@ static void openStatTable( } /* +** Recommended number of samples for sqlite_stat3 +*/ +#ifndef SQLITE_STAT3_SAMPLES +# define SQLITE_STAT3_SAMPLES 16 +#endif + +/* ** Generate code to do an analysis of all indices associated with ** a single table. */ @@ -119,20 +232,26 @@ static void analyzeOneTable( int iDb; /* Index of database containing pTab */ int regTabname = iMem++; /* Register containing table name */ int regIdxname = iMem++; /* Register containing index name */ - int regSampleno = iMem++; /* Register containing next sample number */ - int regCol = iMem++; /* Content of a column analyzed table */ + int regStat1 = iMem++; /* The stat column of sqlite_stat1 */ +#ifdef SQLITE_ENABLE_STAT3 + int regNumEq = iMem-1; /* Number of instances. Same as regStat1 */ + int regNumLt = iMem++; /* Number of keys less than regSample */ + int regSample = iMem++; /* The next sample value */ + int regNext = iMem++; /* Index of next sample to record */ + int regSpacing = iMem++; /* Spacing between samples */ + int regBigSize = iMem++; /* Always save entries with nEq >= this */ + int regTemp1 = iMem++; /* Intermediate register */ + int regCount = iMem++; /* Number of rows in the table or index */ + int regGosub = iMem++; /* Register holding subroutine return addr */ + int once = 1; /* One-time initialization */ + int shortJump = 0; /* Instruction address */ + int addrStoreStat3 = 0; /* Address of subroutine to wrote to stat3 */ +#endif + int regCol = iMem++; /* Content of a column in analyzed table */ int regRec = iMem++; /* Register holding completed record */ int regTemp = iMem++; /* Temporary use register */ int regRowid = iMem++; /* Rowid for the inserted record */ -#ifdef SQLITE_ENABLE_STAT2 - int addr = 0; /* Instruction address */ - int regTemp2 = iMem++; /* Temporary use register */ - int regSamplerecno = iMem++; /* Index of next sample to record */ - int regRecno = iMem++; /* Current sample index */ - int regLast = iMem++; /* Index of last sample to record */ - int regFirst = iMem++; /* Index of first sample to record */ -#endif v = sqlite3GetVdbe(pParse); if( v==0 || NEVER(pTab==0) ){ @@ -165,13 +284,18 @@ static void analyzeOneTable( for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ int nCol; KeyInfo *pKey; + int addrIfNot; /* address of OP_IfNot */ + int *aChngAddr; /* Array of jump instruction addresses */ if( pOnlyIdx && pOnlyIdx!=pIdx ) continue; + VdbeNoopComment((v, "Begin analysis of %s", pIdx->zName)); nCol = pIdx->nColumn; pKey = sqlite3IndexKeyinfo(pParse, pIdx); if( iMem+1+(nCol*2)>pParse->nMem ){ pParse->nMem = iMem+1+(nCol*2); } + aChngAddr = sqlite3DbMallocRaw(db, sizeof(int)*pIdx->nColumn); + if( aChngAddr==0 ) continue; /* Open a cursor to the index to be analyzed. */ assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) ); @@ -182,31 +306,43 @@ static void analyzeOneTable( /* Populate the register containing the index name. */ sqlite3VdbeAddOp4(v, OP_String8, 0, regIdxname, 0, pIdx->zName, 0); -#ifdef SQLITE_ENABLE_STAT2 +#ifdef SQLITE_ENABLE_STAT3 /* If this iteration of the loop is generating code to analyze the ** first index in the pTab->pIndex list, then register regLast has ** not been populated. In this case populate it now. */ - if( pTab->pIndex==pIdx ){ - sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES, regSamplerecno); - sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES*2-1, regTemp); - sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES*2, regTemp2); - - sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regLast); - sqlite3VdbeAddOp2(v, OP_Null, 0, regFirst); - addr = sqlite3VdbeAddOp3(v, OP_Lt, regSamplerecno, 0, regLast); - sqlite3VdbeAddOp3(v, OP_Divide, regTemp2, regLast, regFirst); - sqlite3VdbeAddOp3(v, OP_Multiply, regLast, regTemp, regLast); - sqlite3VdbeAddOp2(v, OP_AddImm, regLast, SQLITE_INDEX_SAMPLES*2-2); - sqlite3VdbeAddOp3(v, OP_Divide, regTemp2, regLast, regLast); - sqlite3VdbeJumpHere(v, addr); + if( once ){ + once = 0; + sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regCount); + sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_STAT3_SAMPLES, regTemp1); + sqlite3VdbeAddOp3(v, OP_Divide, regTemp1, regCount, regSpacing); + sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_STAT3_SAMPLES/2, regTemp1); + sqlite3VdbeAddOp3(v, OP_Divide, regTemp1, regCount, regBigSize); + + /* Generate code for a subroutine that store the most recent sample + ** in the sqlite_stat3 table + */ + shortJump = sqlite3VdbeAddOp0(v, OP_Goto); + sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 5, regRec, "bbbbb", 0); + VdbeComment((v, "begin stat3 write subroutine")); + sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur+1, regRowid); + sqlite3VdbeAddOp3(v, OP_Insert, iStatCur+1, regRec, regRowid); + sqlite3VdbeAddOp3(v, OP_Add, regNext, regSpacing, regNext); + sqlite3VdbeAddOp1(v, OP_Return, regGosub); + addrStoreStat3 = + sqlite3VdbeAddOp3(v, OP_Ge, regBigSize, shortJump+1, regNumEq); + sqlite3VdbeAddOp3(v, OP_Add, regNumEq, regNumLt, regTemp1); + sqlite3VdbeAddOp3(v, OP_Ge, regNext, shortJump+1, regTemp1); + sqlite3VdbeAddOp1(v, OP_Return, regGosub); + VdbeComment((v, "end stat3 write subroutine")); + sqlite3VdbeJumpHere(v, shortJump); } + /* Reset state registers */ + sqlite3VdbeAddOp2(v, OP_Copy, regSpacing, regNext); + sqlite3VdbeAddOp2(v, OP_Integer, 0, regNumEq); + sqlite3VdbeAddOp2(v, OP_Integer, 0, regNumLt); - /* Zero the regSampleno and regRecno registers. */ - sqlite3VdbeAddOp2(v, OP_Integer, 0, regSampleno); - sqlite3VdbeAddOp2(v, OP_Integer, 0, regRecno); - sqlite3VdbeAddOp2(v, OP_Copy, regFirst, regSamplerecno); -#endif +#endif /* SQLITE_ENABLE_STAT3 */ /* The block of memory cells initialized here is used as follows. ** @@ -236,75 +372,54 @@ static void analyzeOneTable( endOfLoop = sqlite3VdbeMakeLabel(v); sqlite3VdbeAddOp2(v, OP_Rewind, iIdxCur, endOfLoop); topOfLoop = sqlite3VdbeCurrentAddr(v); - sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1); + sqlite3VdbeAddOp2(v, OP_AddImm, iMem, 1); /* Increment row counter */ for(i=0; i<nCol; i++){ CollSeq *pColl; sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, regCol); if( i==0 ){ -#ifdef SQLITE_ENABLE_STAT2 - /* Check if the record that cursor iIdxCur points to contains a - ** value that should be stored in the sqlite_stat2 table. If so, - ** store it. */ - int ne = sqlite3VdbeAddOp3(v, OP_Ne, regRecno, 0, regSamplerecno); - assert( regTabname+1==regIdxname - && regTabname+2==regSampleno - && regTabname+3==regCol - ); - sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL); - sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 4, regRec, "aaab", 0); - sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur+1, regRowid); - sqlite3VdbeAddOp3(v, OP_Insert, iStatCur+1, regRec, regRowid); - - /* Calculate new values for regSamplerecno and regSampleno. - ** - ** sampleno = sampleno + 1 - ** samplerecno = samplerecno+(remaining records)/(remaining samples) - */ - sqlite3VdbeAddOp2(v, OP_AddImm, regSampleno, 1); - sqlite3VdbeAddOp3(v, OP_Subtract, regRecno, regLast, regTemp); - sqlite3VdbeAddOp2(v, OP_AddImm, regTemp, -1); - sqlite3VdbeAddOp2(v, OP_Integer, SQLITE_INDEX_SAMPLES, regTemp2); - sqlite3VdbeAddOp3(v, OP_Subtract, regSampleno, regTemp2, regTemp2); - sqlite3VdbeAddOp3(v, OP_Divide, regTemp2, regTemp, regTemp); - sqlite3VdbeAddOp3(v, OP_Add, regSamplerecno, regTemp, regSamplerecno); - - sqlite3VdbeJumpHere(v, ne); - sqlite3VdbeAddOp2(v, OP_AddImm, regRecno, 1); -#endif - /* Always record the very first row */ - sqlite3VdbeAddOp1(v, OP_IfNot, iMem+1); + addrIfNot = sqlite3VdbeAddOp1(v, OP_IfNot, iMem+1); } assert( pIdx->azColl!=0 ); assert( pIdx->azColl[i]!=0 ); pColl = sqlite3LocateCollSeq(pParse, pIdx->azColl[i]); - sqlite3VdbeAddOp4(v, OP_Ne, regCol, 0, iMem+nCol+i+1, - (char*)pColl, P4_COLLSEQ); + aChngAddr[i] = sqlite3VdbeAddOp4(v, OP_Ne, regCol, 0, iMem+nCol+i+1, + (char*)pColl, P4_COLLSEQ); sqlite3VdbeChangeP5(v, SQLITE_NULLEQ); - } - if( db->mallocFailed ){ - /* If a malloc failure has occurred, then the result of the expression - ** passed as the second argument to the call to sqlite3VdbeJumpHere() - ** below may be negative. Which causes an assert() to fail (or an - ** out-of-bounds write if SQLITE_DEBUG is not defined). */ - return; + VdbeComment((v, "jump if column %d changed", i)); +#ifdef SQLITE_ENABLE_STAT3 + if( i==0 && addrStoreStat3 ){ + sqlite3VdbeAddOp2(v, OP_AddImm, regNumEq, 1); + VdbeComment((v, "incr repeat count")); + } +#endif } sqlite3VdbeAddOp2(v, OP_Goto, 0, endOfLoop); for(i=0; i<nCol; i++){ - int addr2 = sqlite3VdbeCurrentAddr(v) - (nCol*2); + sqlite3VdbeJumpHere(v, aChngAddr[i]); /* Set jump dest for the OP_Ne */ if( i==0 ){ - sqlite3VdbeJumpHere(v, addr2-1); /* Set jump dest for the OP_IfNot */ + sqlite3VdbeJumpHere(v, addrIfNot); /* Jump dest for OP_IfNot */ +#ifdef SQLITE_ENABLE_STAT3 + sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrStoreStat3); + sqlite3VdbeAddOp2(v, OP_Copy, regCol, regSample); + sqlite3VdbeAddOp3(v, OP_Add, regNumEq, regNumLt, regNumLt); + sqlite3VdbeAddOp2(v, OP_Integer, 1, regNumEq); +#endif } - sqlite3VdbeJumpHere(v, addr2); /* Set jump dest for the OP_Ne */ sqlite3VdbeAddOp2(v, OP_AddImm, iMem+i+1, 1); sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, i, iMem+nCol+i+1); } + sqlite3DbFree(db, aChngAddr); - /* End of the analysis loop. */ + /* Always jump here after updating the iMem+1...iMem+1+nCol counters */ sqlite3VdbeResolveLabel(v, endOfLoop); + sqlite3VdbeAddOp2(v, OP_Next, iIdxCur, topOfLoop); sqlite3VdbeAddOp1(v, OP_Close, iIdxCur); +#ifdef SQLITE_ENABLE_STAT3 + sqlite3VdbeAddOp2(v, OP_Gosub, regGosub, addrStoreStat3); +#endif /* Store the results in sqlite_stat1. ** @@ -324,18 +439,18 @@ static void analyzeOneTable( ** If K>0 then it is always the case the D>0 so division by zero ** is never possible. */ - sqlite3VdbeAddOp2(v, OP_SCopy, iMem, regSampleno); + sqlite3VdbeAddOp2(v, OP_SCopy, iMem, regStat1); if( jZeroRows<0 ){ jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, iMem); } for(i=0; i<nCol; i++){ sqlite3VdbeAddOp4(v, OP_String8, 0, regTemp, 0, " ", 0); - sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regSampleno, regSampleno); + sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regStat1, regStat1); sqlite3VdbeAddOp3(v, OP_Add, iMem, iMem+i+1, regTemp); sqlite3VdbeAddOp2(v, OP_AddImm, regTemp, -1); sqlite3VdbeAddOp3(v, OP_Divide, iMem+i+1, regTemp, regTemp); sqlite3VdbeAddOp1(v, OP_ToInt, regTemp); - sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regSampleno, regSampleno); + sqlite3VdbeAddOp3(v, OP_Concat, regTemp, regStat1, regStat1); } sqlite3VdbeAddOp4(v, OP_MakeRecord, regTabname, 3, regRec, "aaa", 0); sqlite3VdbeAddOp2(v, OP_NewRowid, iStatCur, regRowid); @@ -349,9 +464,9 @@ static void analyzeOneTable( if( pTab->pIndex==0 ){ sqlite3VdbeAddOp3(v, OP_OpenRead, iIdxCur, pTab->tnum, iDb); VdbeComment((v, "%s", pTab->zName)); - sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regSampleno); + sqlite3VdbeAddOp2(v, OP_Count, iIdxCur, regStat1); sqlite3VdbeAddOp1(v, OP_Close, iIdxCur); - jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regSampleno); + jZeroRows = sqlite3VdbeAddOp1(v, OP_IfNot, regStat1); }else{ sqlite3VdbeJumpHere(v, jZeroRows); jZeroRows = sqlite3VdbeAddOp0(v, OP_Goto); @@ -365,6 +480,7 @@ static void analyzeOneTable( sqlite3VdbeJumpHere(v, jZeroRows); } + /* ** Generate code that will cause the most recent index analysis to ** be loaded into internal hash tables where is can be used. @@ -518,7 +634,7 @@ static int analysisLoader(void *pData, int argc, char **argv, char **NotUsed){ Index *pIndex; Table *pTable; int i, c, n; - unsigned int v; + tRowcnt v; const char *z; assert( argc==3 ); @@ -561,36 +677,157 @@ static int analysisLoader(void *pData, int argc, char **argv, char **NotUsed){ ** and its contents. */ void sqlite3DeleteIndexSamples(sqlite3 *db, Index *pIdx){ -#ifdef SQLITE_ENABLE_STAT2 +#ifdef SQLITE_ENABLE_STAT3 if( pIdx->aSample ){ int j; - for(j=0; j<SQLITE_INDEX_SAMPLES; j++){ + for(j=0; j<pIdx->nSample; j++){ IndexSample *p = &pIdx->aSample[j]; if( p->eType==SQLITE_TEXT || p->eType==SQLITE_BLOB ){ - sqlite3DbFree(db, p->u.z); + sqlite3_free(p->u.z); } } - sqlite3DbFree(db, pIdx->aSample); + sqlite3_free(pIdx->aSample); } + pIdx->nSample = 0; + pIdx->aSample = 0; #else UNUSED_PARAMETER(db); UNUSED_PARAMETER(pIdx); #endif } +#ifdef SQLITE_ENABLE_STAT3 /* -** Load the content of the sqlite_stat1 and sqlite_stat2 tables. The +** Load content from the sqlite_stat3 table into the Index.aSample[] +** arrays of all indices. +*/ +static int loadStat3(sqlite3 *db, const char *zDb){ + int rc; /* Result codes from subroutines */ + sqlite3_stmt *pStmt = 0; /* An SQL statement being run */ + char *zSql; /* Text of the SQL statement */ + Index *pPrevIdx = 0; /* Previous index in the loop */ + int idx; /* slot in pIdx->aSample[] for next sample */ + int eType; /* Datatype of a sample */ + IndexSample *pSample; /* A slot in pIdx->aSample[] */ + + if( !sqlite3FindTable(db, "sqlite_stat3", zDb) ){ + return SQLITE_OK; + } + + zSql = sqlite3MPrintf(db, + "SELECT idx,count(*) FROM %Q.sqlite_stat3" + " GROUP BY idx", zDb); + if( !zSql ){ + return SQLITE_NOMEM; + } + rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0); + sqlite3DbFree(db, zSql); + if( rc ) return rc; + + while( sqlite3_step(pStmt)==SQLITE_ROW ){ + char *zIndex; /* Index name */ + Index *pIdx; /* Pointer to the index object */ + int nSample; /* Number of samples */ + + zIndex = (char *)sqlite3_column_text(pStmt, 0); + if( zIndex==0 ) continue; + nSample = sqlite3_column_int(pStmt, 1); + if( nSample>255 ) continue; + pIdx = sqlite3FindIndex(db, zIndex, zDb); + if( pIdx==0 ) continue; + assert( pIdx->nSample==0 ); + pIdx->nSample = (u8)nSample; + pIdx->aSample = sqlite3MallocZero( nSample*sizeof(IndexSample) ); + if( pIdx->aSample==0 ){ + db->mallocFailed = 1; + sqlite3_finalize(pStmt); + return SQLITE_NOMEM; + } + } + sqlite3_finalize(pStmt); + + zSql = sqlite3MPrintf(db, + "SELECT idx,nlt,neq,sample FROM %Q.sqlite_stat3" + " ORDER BY idx, nlt", zDb); + if( !zSql ){ + return SQLITE_NOMEM; + } + rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0); + sqlite3DbFree(db, zSql); + if( rc ) return rc; + + while( sqlite3_step(pStmt)==SQLITE_ROW ){ + char *zIndex; /* Index name */ + Index *pIdx; /* Pointer to the index object */ + + zIndex = (char *)sqlite3_column_text(pStmt, 0); + if( zIndex==0 ) continue; + pIdx = sqlite3FindIndex(db, zIndex, zDb); + if( pIdx==0 ) continue; + if( pIdx==pPrevIdx ){ + idx++; + }else{ + pPrevIdx = pIdx; + idx = 0; + } + assert( idx<pIdx->nSample ); + pSample = &pIdx->aSample[idx]; + pSample->nLt = (tRowcnt)sqlite3_column_int64(pStmt, 1); + pSample->nEq = (tRowcnt)sqlite3_column_int64(pStmt, 2); + eType = sqlite3_column_type(pStmt, 3); + pSample->eType = (u8)eType; + switch( eType ){ + case SQLITE_INTEGER: { + pSample->u.i = sqlite3_column_int64(pStmt, 3); + break; + } + case SQLITE_FLOAT: { + pSample->u.r = sqlite3_column_double(pStmt, 3); + break; + } + case SQLITE_NULL: { + break; + } + default: assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB ); { + const char *z = (const char *)( + (eType==SQLITE_BLOB) ? + sqlite3_column_blob(pStmt, 3): + sqlite3_column_text(pStmt, 3) + ); + int n = sqlite3_column_bytes(pStmt, 2); + if( n>0xffff ) n = 0xffff; + pSample->nByte = (u16)n; + if( n < 1){ + pSample->u.z = 0; + }else{ + pSample->u.z = sqlite3Malloc(n); + if( pSample->u.z==0 ){ + db->mallocFailed = 1; + sqlite3_finalize(pStmt); + return SQLITE_NOMEM; + } + memcpy(pSample->u.z, z, n); + } + } + } + } + return sqlite3_finalize(pStmt); +} +#endif /* SQLITE_ENABLE_STAT3 */ + +/* +** Load the content of the sqlite_stat1 and sqlite_stat3 tables. The ** contents of sqlite_stat1 are used to populate the Index.aiRowEst[] -** arrays. The contents of sqlite_stat2 are used to populate the +** arrays. The contents of sqlite_stat3 are used to populate the ** Index.aSample[] arrays. ** ** If the sqlite_stat1 table is not present in the database, SQLITE_ERROR -** is returned. In this case, even if SQLITE_ENABLE_STAT2 was defined -** during compilation and the sqlite_stat2 table is present, no data is +** is returned. In this case, even if SQLITE_ENABLE_STAT3 was defined +** during compilation and the sqlite_stat3 table is present, no data is ** read from it. ** -** If SQLITE_ENABLE_STAT2 was defined during compilation and the -** sqlite_stat2 table is not present in the database, SQLITE_ERROR is +** If SQLITE_ENABLE_STAT3 was defined during compilation and the +** sqlite_stat3 table is not present in the database, SQLITE_ERROR is ** returned. However, in this case, data is read from the sqlite_stat1 ** table (if it is present) before returning. ** @@ -612,8 +849,10 @@ int sqlite3AnalysisLoad(sqlite3 *db, int iDb){ for(i=sqliteHashFirst(&db->aDb[iDb].pSchema->idxHash);i;i=sqliteHashNext(i)){ Index *pIdx = sqliteHashData(i); sqlite3DefaultRowEst(pIdx); +#ifdef SQLITE_ENABLE_STAT3 sqlite3DeleteIndexSamples(db, pIdx); pIdx->aSample = 0; +#endif } /* Check to make sure the sqlite_stat1 table exists */ @@ -625,7 +864,7 @@ int sqlite3AnalysisLoad(sqlite3 *db, int iDb){ /* Load new statistics out of the sqlite_stat1 table */ zSql = sqlite3MPrintf(db, - "SELECT tbl, idx, stat FROM %Q.sqlite_stat1", sInfo.zDatabase); + "SELECT tbl,idx,stat FROM %Q.sqlite_stat1", sInfo.zDatabase); if( zSql==0 ){ rc = SQLITE_NOMEM; }else{ @@ -634,78 +873,10 @@ int sqlite3AnalysisLoad(sqlite3 *db, int iDb){ } - /* Load the statistics from the sqlite_stat2 table. */ -#ifdef SQLITE_ENABLE_STAT2 - if( rc==SQLITE_OK && !sqlite3FindTable(db, "sqlite_stat2", sInfo.zDatabase) ){ - rc = SQLITE_ERROR; - } + /* Load the statistics from the sqlite_stat3 table. */ +#ifdef SQLITE_ENABLE_STAT3 if( rc==SQLITE_OK ){ - sqlite3_stmt *pStmt = 0; - - zSql = sqlite3MPrintf(db, - "SELECT idx,sampleno,sample FROM %Q.sqlite_stat2", sInfo.zDatabase); - if( !zSql ){ - rc = SQLITE_NOMEM; - }else{ - rc = sqlite3_prepare(db, zSql, -1, &pStmt, 0); - sqlite3DbFree(db, zSql); - } - - if( rc==SQLITE_OK ){ - while( sqlite3_step(pStmt)==SQLITE_ROW ){ - char *zIndex; /* Index name */ - Index *pIdx; /* Pointer to the index object */ - - zIndex = (char *)sqlite3_column_text(pStmt, 0); - pIdx = zIndex ? sqlite3FindIndex(db, zIndex, sInfo.zDatabase) : 0; - if( pIdx ){ - int iSample = sqlite3_column_int(pStmt, 1); - if( iSample<SQLITE_INDEX_SAMPLES && iSample>=0 ){ - int eType = sqlite3_column_type(pStmt, 2); - - if( pIdx->aSample==0 ){ - static const int sz = sizeof(IndexSample)*SQLITE_INDEX_SAMPLES; - pIdx->aSample = (IndexSample *)sqlite3DbMallocRaw(0, sz); - if( pIdx->aSample==0 ){ - db->mallocFailed = 1; - break; - } - memset(pIdx->aSample, 0, sz); - } - - assert( pIdx->aSample ); - { - IndexSample *pSample = &pIdx->aSample[iSample]; - pSample->eType = (u8)eType; - if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){ - pSample->u.r = sqlite3_column_double(pStmt, 2); - }else if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){ - const char *z = (const char *)( - (eType==SQLITE_BLOB) ? - sqlite3_column_blob(pStmt, 2): - sqlite3_column_text(pStmt, 2) - ); - int n = sqlite3_column_bytes(pStmt, 2); - if( n>24 ){ - n = 24; - } - pSample->nByte = (u8)n; - if( n < 1){ - pSample->u.z = 0; - }else{ - pSample->u.z = sqlite3DbStrNDup(0, z, n); - if( pSample->u.z==0 ){ - db->mallocFailed = 1; - break; - } - } - } - } - } - } - } - rc = sqlite3_finalize(pStmt); - } + rc = loadStat3(db, sInfo.zDatabase); } #endif |