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Use symbolic names ONEPASS_OFF, ONEPASS_SINGLE, and ONEPASS_MULTI for the

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various modes of the one-pass optimization.

FossilOrigin-Name: 16e56bdadef903c6439a487f2683388aeeb0c625
This commit is contained in:
drh
2015-09-14 14:45:50 +00:00
parent 66336f3755
commit b0264eeca1
8 changed files with 55 additions and 47 deletions
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40
src/delete.c
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@@ -235,7 +235,7 @@ void sqlite3DeleteFrom(
int iDb; /* Database number */
int memCnt = -1; /* Memory cell used for change counting */
int rcauth; /* Value returned by authorization callback */
int eOnePass; /* Non-zero for one-pass algorithm without the FIFO */
int eOnePass; /* ONEPASS_OFF or _SINGLE or _MULTI */
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 */
@@ -400,14 +400,14 @@ void sqlite3DeleteFrom(
** to be deleted, based on the WHERE clause. Set variable eOnePass
** to indicate the strategy used to implement this delete:
**
** 0: Two-pass approach - use a FIFO for rowids/PK values.
** 1: One-pass approach - at most one row deleted.
** 2: One-pass approach - any number of rows may be deleted.
** ONEPASS_OFF: Two-pass approach - use a FIFO for rowids/PK values.
** ONEPASS_SINGLE: One-pass approach - at most one row deleted.
** ONEPASS_MULTI: One-pass approach - any number of rows may be deleted.
*/
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, wcf, iTabCur+1);
if( pWInfo==0 ) goto delete_from_cleanup;
eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
assert( IsVirtual(pTab)==0 || eOnePass==0 );
assert( IsVirtual(pTab)==0 || eOnePass==ONEPASS_OFF );
/* Keep track of the number of rows to be deleted */
if( db->flags & SQLITE_CountRows ){
@@ -428,7 +428,7 @@ void sqlite3DeleteFrom(
if( iKey>pParse->nMem ) pParse->nMem = iKey;
}
if( eOnePass ){
if( eOnePass!=ONEPASS_OFF ){
/* 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. */
@@ -460,7 +460,7 @@ void sqlite3DeleteFrom(
/* If this DELETE cannot use the ONEPASS strategy, this is the
** end of the WHERE loop */
if( eOnePass ){
if( eOnePass!=ONEPASS_OFF ){
addrBypass = sqlite3VdbeMakeLabel(v);
}else{
sqlite3WhereEnd(pWInfo);
@@ -473,7 +473,7 @@ void sqlite3DeleteFrom(
*/
if( !isView ){
int iAddrOnce = 0;
if( eOnePass==2 ){
if( eOnePass==ONEPASS_MULTI ){
iAddrOnce = sqlite3CodeOnce(pParse); VdbeCoverage(v);
}
testcase( IsVirtual(pTab) );
@@ -481,13 +481,13 @@ void sqlite3DeleteFrom(
&iDataCur, &iIdxCur);
assert( pPk || IsVirtual(pTab) || iDataCur==iTabCur );
assert( pPk || IsVirtual(pTab) || iIdxCur==iDataCur+1 );
if( eOnePass==2 ) sqlite3VdbeJumpHere(v, iAddrOnce);
if( eOnePass==ONEPASS_MULTI ) sqlite3VdbeJumpHere(v, iAddrOnce);
}
/* Set up a loop over the rowids/primary-keys that were found in the
** where-clause loop above.
*/
if( eOnePass ){
if( eOnePass!=ONEPASS_OFF ){
assert( nKey==nPk ); /* OP_Found will use an unpacked key */
if( aToOpen[iDataCur-iTabCur] ){
assert( pPk!=0 || pTab->pSelect!=0 );
@@ -525,7 +525,7 @@ void sqlite3DeleteFrom(
}
/* End of the loop over all rowids/primary-keys. */
if( eOnePass ){
if( eOnePass!=ONEPASS_OFF ){
sqlite3VdbeResolveLabel(v, addrBypass);
sqlite3WhereEnd(pWInfo);
}else if( pPk ){
@@ -601,13 +601,13 @@ delete_from_cleanup:
** single memory location iPk.
**
** eMode:
** Parameter eMode may be passed either 0, 1 or 2. If it is passed a
** non-zero value, then it is guaranteed that cursor iDataCur already
** points to the row to delete. If it is passed 0, then this function
** must seek iDataCur to the entry identified by iPk and nPk before
** reading from it.
** Parameter eMode may be passed either ONEPASS_OFF (0), ONEPASS_SINGLE, or
** ONEPASS_MULTI. If eMode is not ONEPASS_OFF, then the cursor
** iDataCur already points to the row to delete. If eMode is ONEPASS_OFF
** then this function must seek iDataCur to the entry identified by iPk
** and nPk before reading from it.
**
** If eMode is passed the value 2, then this call is being made as part
** If eMode is ONEPASS_MULTI, then this call is being made as part
** of a ONEPASS delete that affects multiple rows. In this case, if
** iIdxNoSeek is a valid cursor number (>=0), then its position should
** be preserved following the delete operation. Or, if iIdxNoSeek is not
@@ -629,7 +629,7 @@ void sqlite3GenerateRowDelete(
i16 nPk, /* Number of PRIMARY KEY memory cells */
u8 count, /* If non-zero, increment the row change counter */
u8 onconf, /* Default ON CONFLICT policy for triggers */
u8 eMode, /* See explanation above */
u8 eMode, /* ONEPASS_OFF, _SINGLE, or _MULTI. See above */
int iIdxNoSeek /* Cursor number of cursor that does not need seeking */
){
Vdbe *v = pParse->pVdbe; /* Vdbe */
@@ -647,7 +647,7 @@ void sqlite3GenerateRowDelete(
** not attempt to delete it or fire any DELETE triggers. */
iLabel = sqlite3VdbeMakeLabel(v);
opSeek = HasRowid(pTab) ? OP_NotExists : OP_NotFound;
if( eMode==0 ){
if( eMode==ONEPASS_OFF ){
sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
VdbeCoverageIf(v, opSeek==OP_NotExists);
VdbeCoverageIf(v, opSeek==OP_NotFound);
@@ -715,7 +715,7 @@ void sqlite3GenerateRowDelete(
if( iIdxNoSeek>=0 ){
sqlite3VdbeAddOp1(v, OP_Delete, iIdxNoSeek);
}
sqlite3VdbeChangeP5(v, eMode==2);
sqlite3VdbeChangeP5(v, eMode==ONEPASS_MULTI);
}
/* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to