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Add the OP_ColumnsUsed opcode (when compiled with

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SQLITE_ENABLE_COLUMN_USED_MASK) as a hint to the b-tree layer as to which
columns of a btree cursor will be used.

FossilOrigin-Name: 711a176cbfad5dde6defa9648fba6d0d663af134
This commit is contained in:
drh
2015-06-12 12:54:15 +00:00
parent aca55cfec3 97bae794c2
commit 36b80349b7
8 changed files with 75 additions and 30 deletions
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19
src/where.c
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@@ -4213,6 +4213,10 @@ WhereInfo *sqlite3WhereBegin(
SQLITE_INT_TO_PTR(n), P4_INT32);
assert( n<=pTab->nCol );
}
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, pTabItem->iCursor, 0, 0,
(const u8*)&pTabItem->colUsed, P4_INT64);
#endif
}else{
sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
}
@@ -4258,6 +4262,21 @@ WhereInfo *sqlite3WhereBegin(
sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ); /* Hint to COMDB2 */
}
VdbeComment((v, "%s", pIx->zName));
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
{
u64 colUsed = 0;
int ii, jj;
for(ii=0; ii<pIx->nColumn; ii++){
jj = pIx->aiColumn[ii];
if( jj<0 ) continue;
if( jj>63 ) jj = 63;
if( (pTabItem->colUsed & MASKBIT(jj))==0 ) continue;
colUsed |= ((u64)1)<<(ii<63 ? ii : 63);
}
sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, iIndexCur, 0, 0,
(u8*)&colUsed, P4_INT64);
}
#endif /* SQLITE_ENABLE_COLUMN_USED_MASK */
}
}
if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);