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Optimize the "subprog IS NULL" constraint.

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FossilOrigin-Name: ca8c5f028b9f6f32639c8bc9df5dc02537e21385fcbe7e1ae600c640977ea0d5
This commit is contained in:
drh
2020-03-24 18:41:58 +00:00
parent cf08f08d2c
commit 7797207554
3 changed files with 33 additions and 21 deletions
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40
src/vdbevtab.c
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@@ -34,6 +34,7 @@ struct bytecodevtab_cursor {
int iRowid; /* The rowid of the output table */
int iAddr; /* Address */
int needFinalize; /* Cursors owns pStmt and must finalize it */
int showSubprograms; /* Provide a listing of subprograms */
Op *aOp; /* Operand array */
char *zP4; /* Rendered P4 value */
Mem sub; /* Subprograms */
@@ -135,8 +136,13 @@ static int bytecodevtabNext(sqlite3_vtab_cursor *cur){
sqlite3_free(pCur->zP4);
pCur->zP4 = 0;
}
rc = sqlite3VdbeNextOpcode((Vdbe*)pCur->pStmt, &pCur->sub, 0,
&pCur->iRowid, &pCur->iAddr, &pCur->aOp);
rc = sqlite3VdbeNextOpcode(
(Vdbe*)pCur->pStmt,
pCur->showSubprograms ? &pCur->sub : 0,
0,
&pCur->iRowid,
&pCur->iAddr,
&pCur->aOp);
if( rc!=SQLITE_OK ){
sqlite3VdbeMemSetNull(&pCur->sub);
pCur->aOp = 0;
@@ -228,10 +234,10 @@ static int bytecodevtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
}
/*
** Initialize a cursor to use a new
** to the first row of output. This method is always called at least
** once prior to any call to bytecodevtabColumn() or bytecodevtabRowid() or
** bytecodevtabEof().
** Initialize a cursor.
**
** idxNum==0 means show all subprograms
** idxNum==1 means show only the main bytecode and omit subprograms.
*/
static int bytecodevtabFilter(
sqlite3_vtab_cursor *pVtabCursor,
@@ -245,6 +251,7 @@ static int bytecodevtabFilter(
bytecodevtabCursorClear(pCur);
pCur->iRowid = 0;
pCur->iAddr = 0;
pCur->showSubprograms = idxNum==0;
assert( argc==1 );
if( sqlite3_value_type(argv[0])==SQLITE_TEXT ){
const char *zSql = (const char*)sqlite3_value_text(argv[0]);
@@ -279,16 +286,21 @@ static int bytecodevtabBestIndex(
){
int i;
int rc = SQLITE_CONSTRAINT;
struct sqlite3_index_constraint *p;
pIdxInfo->estimatedCost = (double)100;
pIdxInfo->estimatedRows = 100;
for(i=0; i<pIdxInfo->nConstraint; i++){
if( pIdxInfo->aConstraint[i].usable==0 ) continue;
if( pIdxInfo->aConstraint[i].op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
if( pIdxInfo->aConstraint[i].iColumn!=9 ) continue;
rc = SQLITE_OK;
pIdxInfo->aConstraintUsage[i].omit = 1;
pIdxInfo->aConstraintUsage[i].argvIndex = 1;
break;
pIdxInfo->idxNum = 0;
for(i=0, p=pIdxInfo->aConstraint; i<pIdxInfo->nConstraint; i++, p++){
if( p->usable==0 ) continue;
if( p->op==SQLITE_INDEX_CONSTRAINT_EQ && p->iColumn==9 ){
rc = SQLITE_OK;
pIdxInfo->aConstraintUsage[i].omit = 1;
pIdxInfo->aConstraintUsage[i].argvIndex = 1;
}
if( p->op==SQLITE_INDEX_CONSTRAINT_ISNULL && p->iColumn==8 ){
pIdxInfo->aConstraintUsage[i].omit = 1;
pIdxInfo->idxNum = 1;
}
}
return rc;
}