diff options
Diffstat (limited to 'src/wherecode.c')
| -rw-r--r-- | src/wherecode.c | 51 |
1 files changed, 50 insertions, 1 deletions
diff --git a/src/wherecode.c b/src/wherecode.c index 4fd7399ef..fea397c54 100644 --- a/src/wherecode.c +++ b/src/wherecode.c @@ -747,6 +747,55 @@ static void codeCursorHint( #endif /* SQLITE_ENABLE_CURSOR_HINTS */ /* +** Cursor iCur is open on an intkey b-tree (a table). Register iRowid contains +** a rowid value just read from cursor iIdxCur, open on index pIdx. This +** function generates code to do a deferred seek of cursor iCur to the +** rowid stored in register iRowid. +** +** Normally, this is just: +** +** OP_Seek $iCur $iRowid +** +** However, if the scan currently being coded is a branch of an OR-loop and +** the statement currently being coded is a SELECT, then P3 of the OP_Seek +** is set to iIdxCur and P4 is set to point to an array of integers +** containing one entry for each column of the table cursor iCur is open +** on. For each table column, if the column is the i'th column of the +** index, then the corresponding array entry is set to (i+1). If the column +** does not appear in the index at all, the array entry is set to 0. +*/ +static void codeDeferredSeek( + WhereInfo *pWInfo, /* Where clause context */ + Index *pIdx, /* Index scan is using */ + int iCur, /* Cursor for IPK b-tree */ + int iRowid, /* Register containing rowid to seek to */ + int iIdxCur /* Index cursor */ +){ + Parse *pParse = pWInfo->pParse; /* Parse context */ + Vdbe *v = pParse->pVdbe; /* Vdbe to generate code within */ + + assert( iIdxCur>0 ); + assert( pIdx->aiColumn[pIdx->nColumn-1]==-1 ); + + sqlite3VdbeAddOp3(v, OP_Seek, iCur, iRowid, iIdxCur); + if( (pWInfo->wctrlFlags & WHERE_FORCE_TABLE) + && sqlite3ParseToplevel(pParse)->writeMask==0 + ){ + int i; + Table *pTab = pIdx->pTable; + int *ai = (int*)sqlite3DbMallocZero(pParse->db, sizeof(int)*(pTab->nCol+1)); + if( ai ){ + ai[0] = pTab->nCol; + for(i=0; i<pIdx->nColumn-1; i++){ + assert( pIdx->aiColumn[i]<pTab->nCol ); + if( pIdx->aiColumn[i]>=0 ) ai[pIdx->aiColumn[i]+1] = i+1; + } + sqlite3VdbeChangeP4(v, -1, (char*)ai, P4_INTARRAY); + } + } +} + +/* ** Generate code for the start of the iLevel-th loop in the WHERE clause ** implementation described by pWInfo. */ @@ -1232,7 +1281,7 @@ Bitmask sqlite3WhereCodeOneLoopStart( sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iRowidReg); VdbeCoverage(v); }else{ - sqlite3VdbeAddOp2(v, OP_Seek, iCur, iRowidReg); /* Deferred seek */ + codeDeferredSeek(pWInfo, pIdx, iCur, iRowidReg, iIdxCur); } }else if( iCur!=iIdxCur ){ Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable); |