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-rw-r--r--src/update.c185
1 files changed, 108 insertions, 77 deletions
diff --git a/src/update.c b/src/update.c
index aa13e7f7d..fba7762aa 100644
--- a/src/update.c
+++ b/src/update.c
@@ -134,9 +134,9 @@ void sqlite3Update(
/* Register Allocations */
int regRowCount = 0; /* A count of rows changed */
- int regOldRowid; /* The old rowid */
- int regNewRowid; /* The new rowid */
- int regNew; /* Content of the NEW.* table in triggers */
+ int regOldRowid = 0; /* The old rowid */
+ int regNewRowid = 0; /* The new rowid */
+ int regNew = 0; /* Content of the NEW.* table in triggers */
int regOld = 0; /* Content of OLD.* table in triggers */
int regRowSet = 0; /* Rowset of rows to be updated */
int regKey = 0; /* composite PRIMARY KEY value */
@@ -300,29 +300,20 @@ void sqlite3Update(
if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
sqlite3BeginWriteOperation(pParse, 1, iDb);
-#ifndef SQLITE_OMIT_VIRTUALTABLE
- /* Virtual tables must be handled separately */
- if( IsVirtual(pTab) ){
- updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
- pWhere, onError);
- pWhere = 0;
- pTabList = 0;
- goto update_cleanup;
- }
-#endif
-
/* Allocate required registers. */
- regRowSet = ++pParse->nMem;
- regOldRowid = regNewRowid = ++pParse->nMem;
- if( chngPk || pTrigger || hasFK ){
- regOld = pParse->nMem + 1;
+ if( !IsVirtual(pTab) ){
+ regRowSet = ++pParse->nMem;
+ regOldRowid = regNewRowid = ++pParse->nMem;
+ if( chngPk || pTrigger || hasFK ){
+ regOld = pParse->nMem + 1;
+ pParse->nMem += pTab->nCol;
+ }
+ if( chngKey || pTrigger || hasFK ){
+ regNewRowid = ++pParse->nMem;
+ }
+ regNew = pParse->nMem + 1;
pParse->nMem += pTab->nCol;
}
- if( chngKey || pTrigger || hasFK ){
- regNewRowid = ++pParse->nMem;
- }
- regNew = pParse->nMem + 1;
- pParse->nMem += pTab->nCol;
/* Start the view context. */
if( isView ){
@@ -345,6 +336,15 @@ void sqlite3Update(
goto update_cleanup;
}
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+ /* Virtual tables must be handled separately */
+ if( IsVirtual(pTab) ){
+ updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
+ pWhere, onError);
+ goto update_cleanup;
+ }
+#endif
+
/* Begin the database scan
*/
if( HasRowid(pTab) ){
@@ -384,7 +384,7 @@ void sqlite3Update(
if( pWInfo==0 ) goto update_cleanup;
okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
for(i=0; i<nPk; i++){
- assert( pPk->aiColumn[i]>=(-1) );
+ assert( pPk->aiColumn[i]>=0 );
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, pPk->aiColumn[i],
iPk+i);
}
@@ -507,7 +507,6 @@ void sqlite3Update(
newmask = sqlite3TriggerColmask(
pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
);
- /*sqlite3VdbeAddOp3(v, OP_Null, 0, regNew, regNew+pTab->nCol-1);*/
for(i=0; i<pTab->nCol; i++){
if( i==pTab->iPKey ){
sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
@@ -698,21 +697,23 @@ update_cleanup:
/*
** Generate code for an UPDATE of a virtual table.
**
-** The strategy is that we create an ephemeral table that contains
+** There are two possible strategies - the default and the special
+** "onepass" strategy. Onepass is only used if the virtual table
+** implementation indicates that pWhere may match at most one row.
+**
+** The default strategy is to create an ephemeral table that contains
** for each row to be changed:
**
** (A) The original rowid of that row.
-** (B) The revised rowid for the row. (note1)
+** (B) The revised rowid for the row.
** (C) The content of every column in the row.
**
-** Then we loop over this ephemeral table and for each row in
-** the ephemeral table call VUpdate.
-**
-** When finished, drop the ephemeral table.
+** Then loop through the contents of this ephemeral table executing a
+** VUpdate for each row. When finished, drop the ephemeral table.
**
-** (note1) Actually, if we know in advance that (A) is always the same
-** as (B) we only store (A), then duplicate (A) when pulling
-** it out of the ephemeral table before calling VUpdate.
+** The "onepass" strategy does not use an ephemeral table. Instead, it
+** stores the same values (A, B and C above) in a register array and
+** makes a single invocation of VUpdate.
*/
static void updateVirtualTable(
Parse *pParse, /* The parsing context */
@@ -725,65 +726,95 @@ static void updateVirtualTable(
int onError /* ON CONFLICT strategy */
){
Vdbe *v = pParse->pVdbe; /* Virtual machine under construction */
- ExprList *pEList = 0; /* The result set of the SELECT statement */
- Select *pSelect = 0; /* The SELECT statement */
- Expr *pExpr; /* Temporary expression */
int ephemTab; /* Table holding the result of the SELECT */
int i; /* Loop counter */
- int addr; /* Address of top of loop */
- int iReg; /* First register in set passed to OP_VUpdate */
sqlite3 *db = pParse->db; /* Database connection */
const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
- SelectDest dest;
-
- /* Construct the SELECT statement that will find the new values for
- ** all updated rows.
- */
- pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, "_rowid_"));
+ WhereInfo *pWInfo;
+ int nArg = 2 + pTab->nCol; /* Number of arguments to VUpdate */
+ int regArg; /* First register in VUpdate arg array */
+ int regRec; /* Register in which to assemble record */
+ int regRowid; /* Register for ephem table rowid */
+ int iCsr = pSrc->a[0].iCursor; /* Cursor used for virtual table scan */
+ int aDummy[2]; /* Unused arg for sqlite3WhereOkOnePass() */
+ int bOnePass; /* True to use onepass strategy */
+ int addr; /* Address of OP_OpenEphemeral */
+
+ /* Allocate nArg registers to martial the arguments to VUpdate. Then
+ ** create and open the ephemeral table in which the records created from
+ ** these arguments will be temporarily stored. */
+ assert( v );
+ ephemTab = pParse->nTab++;
+ addr= sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, nArg);
+ regArg = pParse->nMem + 1;
+ pParse->nMem += nArg;
+ regRec = ++pParse->nMem;
+ regRowid = ++pParse->nMem;
+
+ /* Start scanning the virtual table */
+ pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0,0,WHERE_ONEPASS_DESIRED,0);
+ if( pWInfo==0 ) return;
+
+ /* Populate the argument registers. */
+ sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg);
if( pRowid ){
- pEList = sqlite3ExprListAppend(pParse, pEList,
- sqlite3ExprDup(db, pRowid, 0));
+ sqlite3ExprCode(pParse, pRowid, regArg+1);
+ }else{
+ sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg+1);
}
- assert( pTab->iPKey<0 );
for(i=0; i<pTab->nCol; i++){
if( aXRef[i]>=0 ){
- pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr, 0);
+ sqlite3ExprCode(pParse, pChanges->a[aXRef[i]].pExpr, regArg+2+i);
}else{
- pExpr = sqlite3Expr(db, TK_ID, pTab->aCol[i].zName);
+ sqlite3VdbeAddOp3(v, OP_VColumn, iCsr, i, regArg+2+i);
}
- pEList = sqlite3ExprListAppend(pParse, pEList, pExpr);
}
- pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
-
- /* Create the ephemeral table into which the update results will
- ** be stored.
- */
- assert( v );
- ephemTab = pParse->nTab++;
- /* fill the ephemeral table
- */
- sqlite3SelectDestInit(&dest, SRT_EphemTab, ephemTab);
- sqlite3Select(pParse, pSelect, &dest);
-
- /* Generate code to scan the ephemeral table and call VUpdate. */
- iReg = ++pParse->nMem;
- pParse->nMem += pTab->nCol+1;
- addr = sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0); VdbeCoverage(v);
- sqlite3VdbeAddOp3(v, OP_Column, ephemTab, 0, iReg);
- sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
- for(i=0; i<pTab->nCol; i++){
- sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
+ bOnePass = sqlite3WhereOkOnePass(pWInfo, aDummy);
+
+ if( bOnePass ){
+ /* If using the onepass strategy, no-op out the OP_OpenEphemeral coded
+ ** above. Also, if this is a top-level parse (not a trigger), clear the
+ ** multi-write flag so that the VM does not open a statement journal */
+ sqlite3VdbeChangeToNoop(v, addr);
+ if( sqlite3IsToplevel(pParse) ){
+ pParse->isMultiWrite = 0;
+ }
+ }else{
+ /* Create a record from the argument register contents and insert it into
+ ** the ephemeral table. */
+ sqlite3VdbeAddOp3(v, OP_MakeRecord, regArg, nArg, regRec);
+ sqlite3VdbeAddOp2(v, OP_NewRowid, ephemTab, regRowid);
+ sqlite3VdbeAddOp3(v, OP_Insert, ephemTab, regRec, regRowid);
+ }
+
+
+ if( bOnePass==0 ){
+ /* End the virtual table scan */
+ sqlite3WhereEnd(pWInfo);
+
+ /* Begin scannning through the ephemeral table. */
+ addr = sqlite3VdbeAddOp1(v, OP_Rewind, ephemTab); VdbeCoverage(v);
+
+ /* Extract arguments from the current row of the ephemeral table and
+ ** invoke the VUpdate method. */
+ for(i=0; i<nArg; i++){
+ sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i, regArg+i);
+ }
}
sqlite3VtabMakeWritable(pParse, pTab);
- sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVTab, P4_VTAB);
+ sqlite3VdbeAddOp4(v, OP_VUpdate, 0, nArg, regArg, pVTab, P4_VTAB);
sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
sqlite3MayAbort(pParse);
- sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1); VdbeCoverage(v);
- sqlite3VdbeJumpHere(v, addr);
- sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
- /* Cleanup */
- sqlite3SelectDelete(db, pSelect);
+ /* End of the ephemeral table scan. Or, if using the onepass strategy,
+ ** jump to here if the scan visited zero rows. */
+ if( bOnePass==0 ){
+ sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1); VdbeCoverage(v);
+ sqlite3VdbeJumpHere(v, addr);
+ sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
+ }else{
+ sqlite3WhereEnd(pWInfo);
+ }
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-18 15:59:11 +0000