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-rw-r--r--src/delete.c246
1 files changed, 148 insertions, 98 deletions
diff --git a/src/delete.c b/src/delete.c
index 9ebb56eca..e43072235 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -227,20 +227,34 @@ void sqlite3DeleteFrom(
Vdbe *v; /* The virtual database engine */
Table *pTab; /* The table from which records will be deleted */
const char *zDb; /* Name of database holding pTab */
- int end, addr = 0; /* A couple addresses of generated code */
int i; /* Loop counter */
WhereInfo *pWInfo; /* Information about the WHERE clause */
Index *pIdx; /* For looping over indices of the table */
int iTabCur; /* Cursor number for the table */
int iDataCur; /* VDBE cursor for the canonical data source */
int iIdxCur; /* Cursor number of the first index */
+ int nIdx; /* Number of indices */
sqlite3 *db; /* Main database structure */
AuthContext sContext; /* Authorization context */
NameContext sNC; /* Name context to resolve expressions in */
int iDb; /* Database number */
int memCnt = -1; /* Memory cell used for change counting */
int rcauth; /* Value returned by authorization callback */
-
+ int okOnePass; /* True for one-pass algorithm without the FIFO */
+ int aiCurOnePass[2]; /* The write cursors opened by WHERE_ONEPASS */
+ u8 *aToOpen = 0; /* Open cursor iTabCur+j if aToOpen[j] is true */
+ Index *pPk; /* The PRIMARY KEY index on the table */
+ int iPk = 0; /* First of nPk registers holding PRIMARY KEY value */
+ i16 nPk = 1; /* Number of columns in the PRIMARY KEY */
+ int iKey; /* Memory cell holding key of row to be deleted */
+ i16 nKey; /* Number of memory cells in the row key */
+ int iEphCur = 0; /* Ephemeral table holding all primary key values */
+ int iRowSet = 0; /* Register for rowset of rows to delete */
+ int addrBypass = 0; /* Address of jump over the delete logic */
+ int addrLoop = 0; /* Top of the delete loop */
+ int addrDelete = 0; /* Jump directly to the delete logic */
+ int addrEphOpen = 0; /* Instruction to open the Ephermeral table */
+
#ifndef SQLITE_OMIT_TRIGGER
int isView; /* True if attempting to delete from a view */
Trigger *pTrigger; /* List of table triggers, if required */
@@ -295,11 +309,11 @@ void sqlite3DeleteFrom(
}
assert(!isView || pTrigger);
- /* Assign cursor number to the table and all its indices.
+ /* Assign cursor numbers to the table and all its indices.
*/
assert( pTabList->nSrc==1 );
iTabCur = pTabList->a[0].iCursor = pParse->nTab++;
- for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+ for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
pParse->nTab++;
}
@@ -372,106 +386,129 @@ void sqlite3DeleteFrom(
}
}else
#endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */
- if( !HasRowid(pTab) ){
- /* There is a WHERE clause on a WITHOUT ROWID table.
+ {
+ if( HasRowid(pTab) ){
+ /* For a rowid table, initialize the RowSet to an empty set */
+ pPk = 0;
+ nPk = 1;
+ iRowSet = ++pParse->nMem;
+ sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
+ }else{
+ /* For a WITHOUT ROWID table, create an ephermeral table used to
+ ** hold all primary keys for rows to be deleted. */
+ pPk = sqlite3PrimaryKeyIndex(pTab);
+ assert( pPk!=0 );
+ nPk = pPk->nKeyCol;
+ iPk = pParse->nMem+1;
+ pParse->nMem += nPk;
+ iEphCur = pParse->nTab++;
+ addrEphOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEphCur, nPk);
+ sqlite3VdbeSetP4KeyInfo(pParse, pPk);
+ }
+
+ /* Construct a query to find the rowid or primary key for every row
+ ** to be deleted, based on the WHERE clause.
*/
- Index *pPk; /* The PRIMARY KEY index on the table */
- int iPk; /* First of nPk memory cells holding PRIMARY KEY value */
- int iEph; /* Ephemeral table holding all primary key values */
- int iKey; /* Key value inserting into iEph */
- i16 nPk; /* Number of components of the PRIMARY KEY */
-
- pPk = sqlite3PrimaryKeyIndex(pTab);
- assert( pPk!=0 );
- nPk = pPk->nKeyCol;
- iPk = pParse->nMem+1;
- pParse->nMem += nPk;
- iKey = ++pParse->nMem;
- iEph = pParse->nTab++;
-
- sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nPk);
- sqlite3VdbeSetP4KeyInfo(pParse, pPk);
- pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, 0, 0);
+ pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0,
+ WHERE_ONEPASS_DESIRED|WHERE_DUPLICATES_OK,
+ iTabCur+1);
if( pWInfo==0 ) goto delete_from_cleanup;
- for(i=0; i<nPk; i++){
- sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, pPk->aiColumn[i],iPk+i);
- }
- sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey,
- sqlite3IndexAffinityStr(v, pPk), P4_TRANSIENT);
- sqlite3VdbeAddOp2(v, OP_IdxInsert, iEph, iKey);
+ okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
+
+ /* Keep track of the number of rows to be deleted */
if( db->flags & SQLITE_CountRows ){
sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
}
- sqlite3WhereEnd(pWInfo);
-
- /* Open cursors for all indices of the table.
- */
- sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite,
- iTabCur, &iDataCur, &iIdxCur);
-
- /* Loop over the primary keys to be deleted. */
- addr = sqlite3VdbeAddOp1(v, OP_Rewind, iEph);
- sqlite3VdbeAddOp2(v, OP_RowKey, iEph, iPk);
-
- /* Delete the row */
- sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
- iPk, 0, 1, OE_Default, 0);
-
- /* End of the delete loop */
- sqlite3VdbeAddOp2(v, OP_Next, iEph, addr+1);
- sqlite3VdbeJumpHere(v, addr);
-
- /* Close the cursors open on the table and its indexes. */
- assert( iDataCur>=iIdxCur );
- for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
- sqlite3VdbeAddOp1(v, OP_Close, iIdxCur+i);
+
+ /* Extract the rowid or primary key for the current row */
+ if( pPk ){
+ for(i=0; i<nPk; i++){
+ sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur,
+ pPk->aiColumn[i], iPk+i);
+ }
+ iKey = iPk;
+ }else{
+ iKey = pParse->nMem + 1;
+ iKey = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iTabCur, iKey, 0);
+ if( iKey>pParse->nMem ) pParse->nMem = iKey;
}
- }else{
- /* There is a WHERE clause on a rowid table. Run a loop that extracts
- ** all rowids to be deleted into a RowSet.
- */
- int iRowSet = ++pParse->nMem; /* Register for rowset of rows to delete */
- int iRowid = ++pParse->nMem; /* Used for storing rowid values. */
- int regRowid; /* Actual register containing rowids */
-
- /* Collect rowids of every row to be deleted.
- */
- sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet);
- pWInfo = sqlite3WhereBegin(
- pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK, 0
- );
- if( pWInfo==0 ) goto delete_from_cleanup;
- regRowid = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iTabCur, iRowid, 0);
- sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, regRowid);
- if( db->flags & SQLITE_CountRows ){
- sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
+
+ if( okOnePass ){
+ /* For ONEPASS, no need to store the rowid/primary-key. There is only
+ ** one, so just keep it in its register(s) and fall through to the
+ ** delete code.
+ */
+ nKey = nPk; /* OP_Found will use an unpacked key */
+ aToOpen = sqlite3DbMallocRaw(db, nIdx+2);
+ if( aToOpen==0 ){
+ sqlite3WhereEnd(pWInfo);
+ goto delete_from_cleanup;
+ }
+ memset(aToOpen, 1, nIdx+1);
+ aToOpen[nIdx+1] = 0;
+ if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0;
+ if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0;
+ if( addrEphOpen ) sqlite3VdbeChangeToNoop(v, addrEphOpen);
+ addrDelete = sqlite3VdbeAddOp0(v, OP_Goto); /* Jump to DELETE logic */
+ }else if( pPk ){
+ /* Construct a composite key for the row to be deleted and remember it */
+ iKey = ++pParse->nMem;
+ nKey = 0; /* Zero tells OP_Found to use a composite key */
+ sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey,
+ sqlite3IndexAffinityStr(v, pPk), P4_TRANSIENT);
+ sqlite3VdbeAddOp2(v, OP_IdxInsert, iEphCur, iKey);
+ }else{
+ /* Get the rowid of the row to be deleted and remember it in the RowSet */
+ nKey = 1; /* OP_Seek always uses a single rowid */
+ sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey);
}
+
+ /* End of the WHERE loop */
sqlite3WhereEnd(pWInfo);
-
- /* Delete every item whose key was written to the list during the
- ** database scan. We have to delete items after the scan is complete
- ** because deleting an item can change the scan order. */
- end = sqlite3VdbeMakeLabel(v);
-
+ if( okOnePass ){
+ /* Bypass the delete logic below if the WHERE loop found zero rows */
+ addrBypass = sqlite3VdbeMakeLabel(v);
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, addrBypass);
+ sqlite3VdbeJumpHere(v, addrDelete);
+ }
+
/* Unless this is a view, open cursors for the table we are
** deleting from and all its indices. If this is a view, then the
** only effect this statement has is to fire the INSTEAD OF
- ** triggers. */
+ ** triggers.
+ */
if( !isView ){
- sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, iTabCur,
+ sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, iTabCur, aToOpen,
&iDataCur, &iIdxCur);
- assert( iDataCur==iTabCur );
- assert( iIdxCur==iDataCur+1 );
+ assert( pPk || iDataCur==iTabCur );
+ assert( pPk || iIdxCur==iDataCur+1 );
}
-
- addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, end, iRowid);
-
+
+ /* Set up a loop over the rowids/primary-keys that were found in the
+ ** where-clause loop above.
+ */
+ if( okOnePass ){
+ /* Just one row. Hence the top-of-loop is a no-op */
+ assert( nKey==nPk ); /* OP_Found will use an unpacked key */
+ if( aToOpen[iDataCur-iTabCur] ){
+ assert( pPk!=0 );
+ sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey);
+ }
+ }else if( pPk ){
+ addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur);
+ sqlite3VdbeAddOp2(v, OP_RowKey, iEphCur, iKey);
+ assert( nKey==0 ); /* OP_Found will use a composite key */
+ }else{
+ addrLoop = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, 0, iKey);
+ assert( nKey==1 );
+ }
+
/* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( IsVirtual(pTab) ){
const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
sqlite3VtabMakeWritable(pParse, pTab);
- sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, (char*)pVTab, P4_VTAB);
+ sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB);
sqlite3VdbeChangeP5(v, OE_Abort);
sqlite3MayAbort(pParse);
}else
@@ -479,21 +516,28 @@ void sqlite3DeleteFrom(
{
int count = (pParse->nested==0); /* True to count changes */
sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
- iRowid, 1, count, OE_Default, 0);
+ iKey, nKey, count, OE_Default, okOnePass);
}
-
- /* End of the delete loop */
- sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
- sqlite3VdbeResolveLabel(v, end);
-
+
+ /* End of the loop over all rowids/primary-keys. */
+ if( okOnePass ){
+ sqlite3VdbeResolveLabel(v, addrBypass);
+ }else if( pPk ){
+ sqlite3VdbeAddOp2(v, OP_Next, iEphCur, addrLoop+1);
+ sqlite3VdbeJumpHere(v, addrLoop);
+ }else{
+ sqlite3VdbeAddOp2(v, OP_Goto, 0, addrLoop);
+ sqlite3VdbeJumpHere(v, addrLoop);
+ }
+
/* Close the cursors open on the table and its indexes. */
if( !isView && !IsVirtual(pTab) ){
- sqlite3VdbeAddOp1(v, OP_Close, iDataCur);
+ if( !pPk ) sqlite3VdbeAddOp1(v, OP_Close, iDataCur);
for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
sqlite3VdbeAddOp1(v, OP_Close, iIdxCur + i);
}
}
- }
+ } /* End non-truncate path */
/* Update the sqlite_sequence table by storing the content of the
** maximum rowid counter values recorded while inserting into
@@ -517,6 +561,7 @@ delete_from_cleanup:
sqlite3AuthContextPop(&sContext);
sqlite3SrcListDelete(db, pTabList);
sqlite3ExprDelete(db, pWhere);
+ sqlite3DbFree(db, aToOpen);
return;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
@@ -583,6 +628,7 @@ void sqlite3GenerateRowDelete(
if( sqlite3FkRequired(pParse, pTab, 0, 0) || pTrigger ){
u32 mask; /* Mask of OLD.* columns in use */
int iCol; /* Iterator used while populating OLD.* */
+ int addrStart; /* Start of BEFORE trigger programs */
/* TODO: Could use temporary registers here. Also could attempt to
** avoid copying the contents of the rowid register. */
@@ -603,15 +649,19 @@ void sqlite3GenerateRowDelete(
}
/* Invoke BEFORE DELETE trigger programs. */
+ addrStart = sqlite3VdbeCurrentAddr(v);
sqlite3CodeRowTrigger(pParse, pTrigger,
TK_DELETE, 0, TRIGGER_BEFORE, pTab, iOld, onconf, iLabel
);
- /* Seek the cursor to the row to be deleted again. It may be that
- ** the BEFORE triggers coded above have already removed the row
- ** being deleted. Do not attempt to delete the row a second time, and
- ** do not fire AFTER triggers. */
- sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
+ /* If any BEFORE triggers were coded, then seek the cursor to the
+ ** row to be deleted again. It may be that the BEFORE triggers moved
+ ** the cursor or of already deleted the row that the cursor was
+ ** pointing to.
+ */
+ if( addrStart<sqlite3VdbeCurrentAddr(v) ){
+ sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
+ }
/* Do FK processing. This call checks that any FK constraints that
** refer to this table (i.e. constraints attached to other tables)
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-18 21:21:10 +0000