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[CBRD-24248] Support NEED_COUNT_ONLY optimization for JOIN #3780

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merged 4 commits into from
Sep 5, 2022
Merged

[CBRD-24248] Support NEED_COUNT_ONLY optimization for JOIN #3780

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967e580
add count only optimiztion for join
shparkcubrid Aug 29, 2022
62ad535
fix that query without join can only skip iteration for index keys
shparkcubrid Aug 29, 2022
db22c75
check if_pred of last scan_ptr
shparkcubrid Aug 30, 2022
80e714e
indent
shparkcubrid Aug 30, 2022
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36 changes: 27 additions & 9 deletions src/query/query_executor.c
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Original file line number Diff line number Diff line change
Expand Up @@ -7861,22 +7861,38 @@ qexec_intprt_fnc (THREAD_ENTRY * thread_p, XASL_NODE * xasl, XASL_STATE * xasl_s
}

agg_ptr = buildvalue->agg_list;
if (!xasl->scan_ptr /* no scan procedure */
&& !xasl->fptr_list /* no path expressions */
&& !xasl->if_pred /* no if predicates */
/* check only one count(*) function
* TO_DO : this routine can be moved to XASL generator */
if (!xasl->fptr_list /* no path expressions */
&& !xasl->instnum_pred /* no instnum predicate */
&& agg_ptr->next == NULL /* no other aggregate functions */
&& agg_ptr->function == PT_COUNT_STAR)
{
/* only one count(*) function */
ACCESS_SPEC_TYPE *specp = xasl->spec_list;
ACCESS_SPEC_TYPE *specp;
bool is_scan_ptr = xasl->scan_ptr ? true : false;
/* get last scan_ptr */
xptr = xasl;
while (xptr->scan_ptr)
{
xptr = xptr->scan_ptr;
}
specp = xptr->spec_list;
assert (specp);

/* count(*) query will scan an index but does not have a data-filter */
if (specp->next == NULL && specp->access == ACCESS_METHOD_INDEX
&& specp->s.cls_node.cls_regu_list_pred == NULL && specp->where_pred == NULL
&& !specp->indexptr->use_iss && !SCAN_IS_INDEX_MRO (&specp->s_id.s.isid))
&& !specp->indexptr->use_iss && !SCAN_IS_INDEX_MRO (&specp->s_id.s.isid)
&& !xptr->if_pred /* no if predicates */ )
{
/* count(*) query will scan an index but does not have a data-filter */
/* there are two optimization for query having count() only
* 1. Skip saving data to temporary files.
* 2. Skip iteration for each index keys (no scan ptr only) */
specp->s_id.s.isid.need_count_only = true;
count_star_with_iscan_opt = true;
if (!is_scan_ptr)
{
count_star_with_iscan_opt = true;
}
}
}
}
Expand Down Expand Up @@ -7942,8 +7958,10 @@ qexec_intprt_fnc (THREAD_ENTRY * thread_p, XASL_NODE * xasl, XASL_STATE * xasl_s

if (count_star_with_iscan_opt)
{
/* count only query without join can skip iteration for index keys */
xasl->curr_spec->s_id.position = S_BEFORE;
xasl->proc.buildvalue.agg_list->accumulator.curr_cnt += (&xasl->curr_spec->s_id)->s.isid.oids_count;
/* may have more scan ranges */
/* may have more OIDs */
continue;
}
/* set scan item as qualified */
Expand Down
13 changes: 9 additions & 4 deletions src/query/scan_manager.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5812,15 +5812,14 @@ scan_next_index_scan (THREAD_ENTRY * thread_p, SCAN_ID * scan_id)
return ret;
}

scan_id->position = S_ON;
isidp->curr_oidno = 0; /* first oid number */
if (isidp->need_count_only == true)
{
/* no more scan is needed. just return */
return S_SUCCESS;
}

scan_id->position = S_ON;
isidp->curr_oidno = 0; /* first oid number */

if (SCAN_IS_INDEX_COVERED (isidp))
{
qfile_close_list (thread_p, isidp->indx_cov.list_id);
Expand Down Expand Up @@ -5857,6 +5856,12 @@ scan_next_index_scan (THREAD_ENTRY * thread_p, SCAN_ID * scan_id)
if (isidp->curr_oidno < oids_cnt - 1)
{
isidp->curr_oidno++;
if (isidp->need_count_only == true)
{
/* no more scan is needed. just return */
return S_SUCCESS;
}

if (!SCAN_IS_INDEX_COVERED (isidp))
{
if (isidp->multi_range_opt.use)
Expand Down Expand Up @@ -5927,13 +5932,13 @@ scan_next_index_scan (THREAD_ENTRY * thread_p, SCAN_ID * scan_id)
return ret;
}

isidp->curr_oidno = 0; /* first oid number */
if (isidp->need_count_only == true)
{
/* no more scan is needed. just return */
return S_SUCCESS;
}

isidp->curr_oidno = 0; /* first oid number */
if (SCAN_IS_INDEX_COVERED (isidp))
{
qfile_close_list (thread_p, isidp->indx_cov.list_id);
Expand Down