diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/build.c | 2 | ||||
| -rw-r--r-- | src/shell.c | 7 | ||||
| -rw-r--r-- | src/wal.c | 32 |
3 files changed, 33 insertions, 8 deletions
diff --git a/src/build.c b/src/build.c index 93fc33108..59c2a7302 100644 --- a/src/build.c +++ b/src/build.c @@ -356,7 +356,7 @@ Table *sqlite3LocateTable( p = sqlite3FindTable(pParse->db, zName, zDbase); if( p==0 ){ const char *zMsg = isView ? "no such view" : "no such table"; -#ifndef SQLITE_OMIT_VIRTUAL_TABLE +#ifndef SQLITE_OMIT_VIRTUALTABLE /* If zName is the not the name of a table in the schema created using ** CREATE, then check to see if it is the name of an virtual table that ** can be an eponymous virtual table. */ diff --git a/src/shell.c b/src/shell.c index da7f78e10..e5eb394ea 100644 --- a/src/shell.c +++ b/src/shell.c @@ -4619,6 +4619,13 @@ int SQLITE_CDECL main(int argc, char **argv){ } data.out = stdout; +#ifdef SQLITE_ENABLE_JSON1 + { + extern int sqlite3_json_init(sqlite3*); + sqlite3_auto_extension((void(*)(void))sqlite3_json_init); + } +#endif + /* Go ahead and open the database file if it already exists. If the ** file does not exist, delay opening it. This prevents empty database ** files from being created if a user mistypes the database name argument @@ -428,6 +428,7 @@ struct Wal { u8 syncHeader; /* Fsync the WAL header if true */ u8 padToSectorBoundary; /* Pad transactions out to the next sector */ WalIndexHdr hdr; /* Wal-index header for current transaction */ + u32 minFrame; /* Ignore wal frames before this one */ const char *zWalName; /* Name of WAL file */ u32 nCkpt; /* Checkpoint sequence counter in the wal-header */ #ifdef SQLITE_DEBUG @@ -2296,12 +2297,27 @@ static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int cnt){ ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry ** instead. ** - ** This does not guarantee that the copy of the wal-index header is up to - ** date before proceeding. That would not be possible without somehow - ** blocking writers. It only guarantees that a dangerous checkpoint or - ** log-wrap (either of which would require an exclusive lock on - ** WAL_READ_LOCK(mxI)) has not occurred since the snapshot was valid. + ** Before checking that the live wal-index header has not changed + ** since it was read, set Wal.minFrame to the first frame in the wal + ** file that has not yet been checkpointed. This client will not need + ** to read any frames earlier than minFrame from the wal file - they + ** can be safely read directly from the database file. + ** + ** Because a ShmBarrier() call is made between taking the copy of + ** nBackfill and checking that the wal-header in shared-memory still + ** matches the one cached in pWal->hdr, it is guaranteed that the + ** checkpointer that set nBackfill was not working with a wal-index + ** header newer than that cached in pWal->hdr. If it were, that could + ** cause a problem. The checkpointer could omit to checkpoint + ** a version of page X that lies before pWal->minFrame (call that version + ** A) on the basis that there is a newer version (version B) of the same + ** page later in the wal file. But if version B happens to like past + ** frame pWal->hdr.mxFrame - then the client would incorrectly assume + ** that it can read version A from the database file. However, since + ** we can guarantee that the checkpointer that set nBackfill could not + ** see any pages past pWal->hdr.mxFrame, this problem does not come up. */ + pWal->minFrame = pInfo->nBackfill+1; walShmBarrier(pWal); if( pInfo->aReadMark[mxI]!=mxReadMark || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr)) @@ -2372,6 +2388,7 @@ int sqlite3WalFindFrame( u32 iRead = 0; /* If !=0, WAL frame to return data from */ u32 iLast = pWal->hdr.mxFrame; /* Last page in WAL for this reader */ int iHash; /* Used to loop through N hash tables */ + int iMinHash; /* This routine is only be called from within a read transaction. */ assert( pWal->readLock>=0 || pWal->lockError ); @@ -2412,7 +2429,8 @@ int sqlite3WalFindFrame( ** This condition filters out entries that were added to the hash ** table after the current read-transaction had started. */ - for(iHash=walFramePage(iLast); iHash>=0 && iRead==0; iHash--){ + iMinHash = walFramePage(pWal->minFrame); + for(iHash=walFramePage(iLast); iHash>=iMinHash && iRead==0; iHash--){ volatile ht_slot *aHash; /* Pointer to hash table */ volatile u32 *aPgno; /* Pointer to array of page numbers */ u32 iZero; /* Frame number corresponding to aPgno[0] */ @@ -2427,7 +2445,7 @@ int sqlite3WalFindFrame( nCollide = HASHTABLE_NSLOT; for(iKey=walHash(pgno); aHash[iKey]; iKey=walNextHash(iKey)){ u32 iFrame = aHash[iKey] + iZero; - if( iFrame<=iLast && aPgno[aHash[iKey]]==pgno ){ + if( iFrame<=iLast && iFrame>=pWal->minFrame && aPgno[aHash[iKey]]==pgno ){ assert( iFrame>iRead || CORRUPT_DB ); iRead = iFrame; } |