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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();

35
dbcon/joblist/joblistfactory.cpp
View File

@@ -1712,29 +1712,24 @@ void parseExecutionPlan(CalpontSelectExecutionPlan* csep, JobInfo& jobInfo,
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. // special case for outer query order by limit -- return all
if (csep->limitNum() != (uint64_t) - 1) if (jobInfo.subId == 0 && csep->hasOrderBy() && !csep->specHandlerProcessed())
{ {
// special case for outer query order by limit -- return all jobInfo.limitCount = (uint64_t) - 1;
if (jobInfo.subId == 0 && csep->hasOrderBy() && !csep->specHandlerProcessed()) }
{
jobInfo.limitCount = (uint64_t) - 1;
}
// support order by and limit in sub-query/union or // support order by and limit in sub-query/union or
// GROUP BY handler processed outer query order // GROUP BY handler processed outer query order
else if (csep->orderByCols().size() > 0) else if (csep->orderByCols().size() > 0)
{ {
addOrderByAndLimit(csep, jobInfo); addOrderByAndLimit(csep, jobInfo);
} }
// limit without order by in any query
else
{
jobInfo.limitStart = csep->limitStart();
jobInfo.limitCount = csep->limitNum();
}
// limit without order by in any query
else
{
jobInfo.limitStart = csep->limitStart();
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

23
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. csep->limitStart(limitOffset);
// do not set in csep. @bug5096. ignore session limit setting for dml csep->limitNum(limitNum);
if (gwi.thd->variables.select_limit == (uint64_t) - 1 &&
!csep->hasOrderBy())
{
csep->limitStart(limitOffset);
csep->limitNum(limitNum);
}
// Pushdown queries w ORDER BY and LIMIT
else if (isPushdownHand && csep->hasOrderBy())
{
csep->limitStart(limitOffset);
csep->limitNum(limitNum);
}
} }
// Pushdown queries with ORDER BY w/o explicit limit // If an explicit limit is not specified, use the system variable value
else if (isPushdownHand && csep->hasOrderBy()) else
{ {
// We must set this to activate LimitedOrderBy in ExeMgr csep->limitNum(gwi.thd->variables.select_limit);
csep->limitNum((uint64_t) - 2);
} }
// We don't currently support limit with correlated subquery // We don't currently support limit with correlated subquery