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Performance improvement in the OP_Column opcode.

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FossilOrigin-Name: 4737cadc414c5f6d256fcceacb19d80d66a8c8e7
This commit is contained in:
drh
2016-05-19 16:58:42 +00:00
parent 21690ff7fc
commit 0eda6cd80d
3 changed files with 17 additions and 17 deletions
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18
src/vdbe.c
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@@ -2485,14 +2485,15 @@ case OP_Column: {
rc = SQLITE_CORRUPT_BKPT;
goto abort_due_to_error;
}
}else if( offset>0 ){ /*OPTIMIZATION-IF-TRUE*/
/* The following goto is an optimization. It can be omitted and
** everything will still work. But OP_Column is measurably faster
** by skipping the subsequent conditional, which is always true.
*/
zData = pC->aRow;
assert( pC->nHdrParsed<=p2 ); /* Conditional skipped */
goto op_column_read_header;
}
/* The following goto is an optimization. It can be omitted and
** everything will still work. But OP_Column is measurably faster
** by skipping the subsequent conditional, which is always true.
*/
assert( pC->nHdrParsed<=p2 ); /* Conditional skipped */
goto op_column_read_header;
}
/* Make sure at least the first p2+1 entries of the header have been
@@ -2502,7 +2503,6 @@ case OP_Column: {
/* If there is more header available for parsing in the record, try
** to extract additional fields up through the p2+1-th field
*/
op_column_read_header:
if( pC->iHdrOffset<aOffset[0] ){
/* Make sure zData points to enough of the record to cover the header. */
if( pC->aRow==0 ){
@@ -2515,11 +2515,11 @@ case OP_Column: {
}
/* Fill in pC->aType[i] and aOffset[i] values through the p2-th field. */
op_column_read_header:
i = pC->nHdrParsed;
offset64 = aOffset[i];
zHdr = zData + pC->iHdrOffset;
zEndHdr = zData + aOffset[0];
assert( i<=p2 && zHdr<zEndHdr );
do{
if( (t = zHdr[0])<0x80 ){
zHdr++;