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-rw-r--r--src/sqliteInt.h1
-rw-r--r--src/vdbe.c33
-rw-r--r--src/vdbeInt.h1
-rw-r--r--src/where.c8
4 files changed, 39 insertions, 4 deletions
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 8f256d52f..7edc04ca4 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2136,6 +2136,7 @@ struct SrcList {
#define WHERE_DISTINCTBY 0x0200 /* pOrderby is really a DISTINCT clause */
#define WHERE_WANT_DISTINCT 0x0400 /* All output needs to be distinct */
#define WHERE_SORTBYGROUP 0x0800 /* Support sqlite3WhereIsSorted() */
+#define WHERE_REOPEN_IDX 0x1000 /* Try to use OP_ReopenIdx */
/* Allowed return values from sqlite3WhereIsDistinct()
*/
diff --git a/src/vdbe.c b/src/vdbe.c
index 86cf8b048..093669a82 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -3205,7 +3205,21 @@ case OP_SetCookie: { /* in3 */
** sequence of the index being opened. Otherwise, if P4 is an integer
** value, it is set to the number of columns in the table.
**
-** See also OpenWrite.
+** See also: OpenWrite, ReopenIdx
+*/
+/* Opcode: ReopenIdx P1 P2 P3 P4 P5
+** Synopsis: root=P2 iDb=P3
+**
+** The ReopenIdx opcode works exactly like ReadOpen except that it first
+** checks to see if the cursor on P1 is already open with a root page
+** number of P2 and if it is this opcode becomes a no-op. In other words,
+** if the cursor is already open, do not reopen it.
+**
+** The ReopenIdx opcode may only be used with P5==0 and with P4 being
+** a P4_KEYINFO object. Furthermore, the P3 value must be the same as
+** every other ReopenIdx or OpenRead for the same cursor number.
+**
+** See the OpenRead opcode documentation for additional information.
*/
/* Opcode: OpenWrite P1 P2 P3 P4 P5
** Synopsis: root=P2 iDb=P3
@@ -3227,6 +3241,19 @@ case OP_SetCookie: { /* in3 */
**
** See also OpenRead.
*/
+case OP_ReopenIdx: {
+ VdbeCursor *pCur;
+
+ assert( pOp->p5==0 );
+ assert( pOp->p4type==P4_KEYINFO );
+ pCur = p->apCsr[pOp->p1];
+ if( pCur && pCur->pgnoRoot==pOp->p2 ){
+ assert( pCur->iDb==pOp->p3 ); /* Guaranteed by the code generator */
+ break;
+ }
+ /* If the cursor is not currently open or is open on a different
+ ** index, then fall through into OP_OpenRead to force a reopen */
+}
case OP_OpenRead:
case OP_OpenWrite: {
int nField;
@@ -3241,7 +3268,8 @@ case OP_OpenWrite: {
assert( (pOp->p5&(OPFLAG_P2ISREG|OPFLAG_BULKCSR))==pOp->p5 );
assert( pOp->opcode==OP_OpenWrite || pOp->p5==0 );
assert( p->bIsReader );
- assert( pOp->opcode==OP_OpenRead || p->readOnly==0 );
+ assert( pOp->opcode==OP_OpenRead || pOp->opcode==OP_ReopenIdx
+ || p->readOnly==0 );
if( p->expired ){
rc = SQLITE_ABORT;
@@ -3298,6 +3326,7 @@ case OP_OpenWrite: {
if( pCur==0 ) goto no_mem;
pCur->nullRow = 1;
pCur->isOrdered = 1;
+ pCur->pgnoRoot = p2;
rc = sqlite3BtreeCursor(pX, p2, wrFlag, pKeyInfo, pCur->pCursor);
pCur->pKeyInfo = pKeyInfo;
assert( OPFLAG_BULKCSR==BTREE_BULKLOAD );
diff --git a/src/vdbeInt.h b/src/vdbeInt.h
index d629802a6..f541aa717 100644
--- a/src/vdbeInt.h
+++ b/src/vdbeInt.h
@@ -76,6 +76,7 @@ struct VdbeCursor {
Bool useRandomRowid:1;/* Generate new record numbers semi-randomly */
Bool isTable:1; /* True if a table requiring integer keys */
Bool isOrdered:1; /* True if the underlying table is BTREE_UNORDERED */
+ Pgno pgnoRoot; /* Root page of the open btree cursor */
sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */
i64 seqCount; /* Sequence counter */
i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
diff --git a/src/where.c b/src/where.c
index 284f141ff..ff18d5d4e 100644
--- a/src/where.c
+++ b/src/where.c
@@ -3422,6 +3422,7 @@ static Bitmask codeOneLoopStart(
int iRetInit; /* Address of regReturn init */
int untestedTerms = 0; /* Some terms not completely tested */
int ii; /* Loop counter */
+ u16 wctrlFlags; /* Flags for sub-WHERE clause */
Expr *pAndExpr = 0; /* An ".. AND (...)" expression */
Table *pTab = pTabItem->pTab;
@@ -3517,6 +3518,8 @@ static Bitmask codeOneLoopStart(
** eliminating duplicates from other WHERE clauses, the action for each
** sub-WHERE clause is to to invoke the main loop body as a subroutine.
*/
+ wctrlFlags = WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
+ WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY;
for(ii=0; ii<pOrWc->nTerm; ii++){
WhereTerm *pOrTerm = &pOrWc->a[ii];
if( pOrTerm->leftCursor==iCur || (pOrTerm->eOperator & WO_AND)!=0 ){
@@ -3529,8 +3532,7 @@ static Bitmask codeOneLoopStart(
}
/* Loop through table entries that match term pOrTerm. */
pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
- WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
- WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY, iCovCur);
+ wctrlFlags, iCovCur);
assert( pSubWInfo || pParse->nErr || db->mallocFailed );
if( pSubWInfo ){
WhereLoop *pSubLoop;
@@ -3621,6 +3623,7 @@ static Bitmask codeOneLoopStart(
){
assert( pSubWInfo->a[0].iIdxCur==iCovCur );
pCov = pSubLoop->u.btree.pIndex;
+ wctrlFlags |= WHERE_REOPEN_IDX;
}else{
pCov = 0;
}
@@ -6219,6 +6222,7 @@ WhereInfo *sqlite3WhereBegin(
pWInfo->aiCurOnePass[1] = iIndexCur;
}else if( iIdxCur && (wctrlFlags & WHERE_ONETABLE_ONLY)!=0 ){
iIndexCur = iIdxCur;
+ if( wctrlFlags & WHERE_REOPEN_IDX ) op = OP_ReopenIdx;
}else{
iIndexCur = pParse->nTab++;
}