diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/btree.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/btree.c b/src/btree.c index 503a2fb5d..12dcb44cb 100644 --- a/src/btree.c +++ b/src/btree.c @@ -4022,6 +4022,7 @@ static int accessPayload( MemPage *pPage = pCur->apPage[pCur->iPage]; /* Btree page of current entry */ BtShared *pBt = pCur->pBt; /* Btree this cursor belongs to */ #ifdef SQLITE_DIRECT_OVERFLOW_READ + unsigned char * const pBufStart = pBuf; int bEnd; /* True if reading to end of data */ #endif @@ -4149,6 +4150,7 @@ static int accessPayload( ** 4) there is no open write-transaction, and ** 5) the database is not a WAL database, ** 6) all data from the page is being read. + ** 7) at least 4 bytes have already been read into the output buffer ** ** then data can be read directly from the database file into the ** output buffer, bypassing the page-cache altogether. This speeds @@ -4160,9 +4162,11 @@ static int accessPayload( && pBt->inTransaction==TRANS_READ /* (4) */ && (fd = sqlite3PagerFile(pBt->pPager))->pMethods /* (3) */ && pBt->pPage1->aData[19]==0x01 /* (5) */ + && &pBuf[-4]>=pBufStart /* (7) */ ){ u8 aSave[4]; u8 *aWrite = &pBuf[-4]; + assert( aWrite>=pBufStart ); /* hence (7) */ memcpy(aSave, aWrite, 4); rc = sqlite3OsRead(fd, aWrite, a+4, (i64)pBt->pageSize*(nextPage-1)); nextPage = get4byte(aWrite); |