database/mariadb-columnstore-engine
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Code Activity

1. Execution plan now sets limitNum and limitOffset for all cases if an explicit limit is supplied in the query.

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2. Fallback to using sql_select_limit system variable value if an explicit limit is not supplied.
3. Remove checks that did not allow (2^64 - 1) as a valid limit value.
This commit is contained in:
Gagan Goel
2019-09-01 23:22:10 -04:00
parent c3458eaeea
commit af988635d4
3 changed files with 20 additions and 42 deletions
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4
dbcon/joblist/jlf_subquery.cpp
View File

@@ -767,10 +767,6 @@ int doFromSubquery(CalpontExecutionPlan* ep, const string& alias, const string&
void addOrderByAndLimit(CalpontSelectExecutionPlan* csep, JobInfo& jobInfo) void addOrderByAndLimit(CalpontSelectExecutionPlan* csep, JobInfo& jobInfo)
{ {
// make sure there is a LIMIT
if (csep->orderByCols().size() > 0 && csep->limitNum() == (uint64_t) - 1)
return;
jobInfo.limitStart = csep->limitStart(); jobInfo.limitStart = csep->limitStart();
jobInfo.limitCount = csep->limitNum(); jobInfo.limitCount = csep->limitNum();

5
dbcon/joblist/joblistfactory.cpp
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@@ -1711,9 +1711,6 @@ void parseExecutionPlan(CalpontSelectExecutionPlan* csep, JobInfo& jobInfo,
// v-table mode // v-table mode
void makeVtableModeSteps(CalpontSelectExecutionPlan* csep, JobInfo& jobInfo, void makeVtableModeSteps(CalpontSelectExecutionPlan* csep, JobInfo& jobInfo,
JobStepVector& querySteps, JobStepVector& projectSteps, DeliveredTableMap& deliverySteps) JobStepVector& querySteps, JobStepVector& projectSteps, DeliveredTableMap& deliverySteps)
{
// @bug4848, enhance and unify limit handling.
if (csep->limitNum() != (uint64_t) - 1)
{ {
// special case for outer query order by limit -- return all // special case for outer query order by limit -- return all
if (jobInfo.subId == 0 && csep->hasOrderBy() && !csep->specHandlerProcessed()) if (jobInfo.subId == 0 && csep->hasOrderBy() && !csep->specHandlerProcessed())
@@ -1735,8 +1732,6 @@ void makeVtableModeSteps(CalpontSelectExecutionPlan* csep, JobInfo& jobInfo,
jobInfo.limitCount = csep->limitNum(); jobInfo.limitCount = csep->limitNum();
} }
}
// Bug 2123. Added overrideLargeSideEstimate parm below. True if the query was written // Bug 2123. Added overrideLargeSideEstimate parm below. True if the query was written
// with a hint telling us to skip the estimatation process for determining the large side // with a hint telling us to skip the estimatation process for determining the large side
// table and instead use the table order in the from clause. // table and instead use the table order in the from clause.

19
dbcon/mysql/ha_calpont_execplan.cpp
View File

@@ -7842,26 +7842,13 @@ int getSelectPlan(gp_walk_info& gwi, SELECT_LEX& select_lex,
} }
} }
// relate to bug4848. let mysql drive limit when limit session variable set.
// do not set in csep. @bug5096. ignore session limit setting for dml
if (gwi.thd->variables.select_limit == (uint64_t) - 1 &&
!csep->hasOrderBy())
{
csep->limitStart(limitOffset); csep->limitStart(limitOffset);
csep->limitNum(limitNum); csep->limitNum(limitNum);
} }
// Pushdown queries w ORDER BY and LIMIT // If an explicit limit is not specified, use the system variable value
else if (isPushdownHand && csep->hasOrderBy()) else
{ {
csep->limitStart(limitOffset); csep->limitNum(gwi.thd->variables.select_limit);
csep->limitNum(limitNum);
}
}
// Pushdown queries with ORDER BY w/o explicit limit
else if (isPushdownHand && csep->hasOrderBy())
{
// We must set this to activate LimitedOrderBy in ExeMgr
csep->limitNum((uint64_t) - 2);
} }
// We don't currently support limit with correlated subquery // We don't currently support limit with correlated subquery