Only run the OP_OpenRead opcodes for a correlated subquery once, on the initial
iteration. Keep the cursor open for subsequent runs. This was suppose to be a performance enhancement, but it is difficult to come up with a query where is makes a significant difference. Hence, the change is getting parked in a branch. FossilOrigin-Name: 3ad687b7aa908b0e914be48cc8a21af5d07e52d9
This commit is contained in:
drh
@@ -1,5 +1,5 @@
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C In\sthe\scommand-line\sshell\sfor\sCSV\simport,\sif\sthe\slines\sare\s\\r\\n\sterminated\nand\sthe\slast\sfield\sis\sblank,\smake\ssure\san\sempty\sstring\sand\snot\sa\s"\\r"\sstring\nis\simported.
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D 2014-02-26T13:53:34.384
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C Only\srun\sthe\sOP_OpenRead\sopcodes\sfor\sa\scorrelated\ssubquery\sonce,\son\sthe\sinitial\niteration.\sKeep\sthe\scursor\sopen\sfor\ssubsequent\sruns.\sThis\swas\ssuppose\sto\sbe\sa\nperformance\senhancement,\sbut\sit\sis\sdifficult\sto\scome\sup\swith\sa\squery\swhere\nis\smakes\sa\ssignificant\sdifference.\s\sHence,\sthe\schange\sis\sgetting\sparked\nin\sa\sbranch.
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D 2014-02-26T19:05:53.265
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F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
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F Makefile.in 2ef13430cd359f7b361bb863504e227b25cc7f81
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F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
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@@ -172,7 +172,7 @@ F src/complete.c dc1d136c0feee03c2f7550bafc0d29075e36deac
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F src/ctime.c 77779efbe78dd678d84bfb4fc2e87b6b6ad8dccd
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F src/date.c 593c744b2623971e45affd0bde347631bdfa4625
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F src/delete.c cdd57149543bb28304d8f717c243f2a86b1fc280
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F src/expr.c 014b8087a15c4c314bdd798cb1cb0b32693f8b40
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F src/expr.c 0b84f62d653a74e1aa9f7fed39d65be74a32a125
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F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
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F src/fkey.c 5269ef07b100763134f71b889327c333bd0989cf
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F src/func.c f4499b39d66b71825514334ce67b32ff14bd19f5
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@@ -216,12 +216,12 @@ F src/printf.c 85d07756e45d7496d19439dcae3e6e9e0090f269
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F src/random.c d10c1f85b6709ca97278428fd5db5bbb9c74eece
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F src/resolve.c ca8b99d894164435f5c55cb304c1b8121705c51e
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F src/rowset.c 64655f1a627c9c212d9ab497899e7424a34222e0
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F src/select.c 28bff39f9bc5ec618b0719fe3f7b4be9f88b6f02
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F src/select.c c959b4d9eb9b1e1adac37a5f792c9d6d3a7e561d
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F src/shell.c ca2b066ab31793532530e0c2fcf79e99628f3b2b
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F src/sqlite.h.in a2ef671f92747a5a1c8a47bad5c585a8dd9eca80
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F src/sqlite3.rc 11094cc6a157a028b301a9f06b3d03089ea37c3e
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F src/sqlite3ext.h 886f5a34de171002ad46fae8c36a7d8051c190fc
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F src/sqliteInt.h 46dfbe0b58282421188a6c25b6c0c0fae18e0134
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F src/sqliteInt.h 036e187f2b667a8315b949ebe0ed904ba1ba07a9
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F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
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F src/status.c 7ac05a5c7017d0b9f0b4bcd701228b784f987158
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F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
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@@ -290,7 +290,7 @@ F src/vtab.c 21b932841e51ebd7d075e2d0ad1415dce8d2d5fd
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F src/wal.c 76e7fc6de229bea8b30bb2539110f03a494dc3a8
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F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
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F src/walker.c 11edb74d587bc87b33ca96a5173e3ec1b8389e45
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F src/where.c 6042e1a377cf7dc72c10493269ed75e276275cd8
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F src/where.c 655b8fc1858f58268945886648f98ca855c78dad
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F src/whereInt.h 921f935af8b684ffb49705610bda7284db1db138
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F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
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F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
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@@ -1152,7 +1152,10 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
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F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
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F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
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F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
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P dca1945aeb3fb005263f9be00ee8e72b966ae303
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R 4bbcd8ca02f23a972c97ceb5ec0d3c0c
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P 9c2e7612cd137895e13ee872e668ce1216719d85
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R e4da2fed75cedad3cb42445a5f266f50
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T *branch * open-only-once
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T *sym-open-only-once *
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T -sym-trunk *
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U drh
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Z 998297c355a76316139497aa81dafb02
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Z e719204d25b226ef45e13c0c8ac591b5
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+1
-1
@@ -1 +1 @@
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9c2e7612cd137895e13ee872e668ce1216719d85
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3ad687b7aa908b0e914be48cc8a21af5d07e52d9
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@@ -1868,6 +1868,7 @@ int sqlite3CodeSubselect(
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pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0,
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&sqlite3IntTokens[1]);
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pSel->iLimit = 0;
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dest.wctrlFlags |= WHERE_OPEN_ONCE;
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if( sqlite3Select(pParse, pSel, &dest) ){
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return 0;
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}
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+4
-1
@@ -37,6 +37,7 @@ static void clearSelect(sqlite3 *db, Select *p){
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*/
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void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
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pDest->eDest = (u8)eDest;
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pDest->wctrlFlags = 0;
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pDest->iSDParm = iParm;
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pDest->affSdst = 0;
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pDest->iSdst = 0;
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@@ -1927,6 +1928,7 @@ static void generateWithRecursiveQuery(
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** the value for the recursive-table. Store the results in the Queue.
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*/
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p->pPrior = 0;
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destQueue.wctrlFlags |= WHERE_OPEN_ONCE;
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sqlite3Select(pParse, p, &destQueue);
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assert( p->pPrior==0 );
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p->pPrior = pSetup;
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@@ -4727,7 +4729,8 @@ int sqlite3Select(
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if( !isAgg && pGroupBy==0 ){
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/* No aggregate functions and no GROUP BY clause */
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u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0);
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u16 wctrlFlags = (sDistinct.isTnct ? WHERE_WANT_DISTINCT : 0)
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| pDest->wctrlFlags;
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/* Begin the database scan. */
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pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pOrderBy, p->pEList,
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@@ -2075,6 +2075,7 @@ struct SrcList {
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#define WHERE_GROUPBY 0x0100 /* pOrderBy is really a GROUP BY */
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#define WHERE_DISTINCTBY 0x0200 /* pOrderby is really a DISTINCT clause */
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#define WHERE_WANT_DISTINCT 0x0400 /* All output needs to be distinct */
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#define WHERE_OPEN_ONCE 0x0800 /* Open on first iteration only */
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/* Allowed return values from sqlite3WhereIsDistinct()
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*/
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@@ -2269,6 +2270,7 @@ struct Select {
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struct SelectDest {
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u8 eDest; /* How to dispose of the results. On of SRT_* above. */
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char affSdst; /* Affinity used when eDest==SRT_Set */
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u16 wctrlFlags; /* Extra flags for sqlite3WhereBegin() */
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int iSDParm; /* A parameter used by the eDest disposal method */
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int iSdst; /* Base register where results are written */
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int nSdst; /* Number of registers allocated */
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+7
-1
@@ -5673,6 +5673,7 @@ WhereInfo *sqlite3WhereBegin(
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Table *pTab; /* Table to open */
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int iDb; /* Index of database containing table/index */
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struct SrcList_item *pTabItem;
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int addrOnce = 0;
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pTabItem = &pTabList->a[pLevel->iFrom];
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pTab = pTabItem->pTab;
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@@ -5697,6 +5698,10 @@ WhereInfo *sqlite3WhereBegin(
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op = OP_OpenWrite;
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pWInfo->aiCurOnePass[0] = pTabItem->iCursor;
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};
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if( wctrlFlags & WHERE_OPEN_ONCE ){
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addrOnce = sqlite3CodeOnce(pParse);
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VdbeCoverage(v);
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}
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sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op);
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assert( pTabItem->iCursor==pLevel->iTabCur );
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testcase( !pWInfo->okOnePass && pTab->nCol==BMS-1 );
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@@ -5740,6 +5745,7 @@ WhereInfo *sqlite3WhereBegin(
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sqlite3VdbeSetP4KeyInfo(pParse, pIx);
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VdbeComment((v, "%s", pIx->zName));
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}
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if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
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if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);
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notReady &= ~getMask(&pWInfo->sMaskSet, pTabItem->iCursor);
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}
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@@ -5897,7 +5903,7 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
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*/
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if( (pTab->tabFlags & TF_Ephemeral)==0
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&& pTab->pSelect==0
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&& (pWInfo->wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0
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&& (pWInfo->wctrlFlags & (WHERE_OMIT_OPEN_CLOSE|WHERE_OPEN_ONCE))==0
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){
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int ws = pLoop->wsFlags;
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if( !pWInfo->okOnePass && (ws & WHERE_IDX_ONLY)==0 ){
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