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Code Issues

Minor adjustments to the join order selection.

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This commit is contained in:
dimitr 2015-03-06 10:20:17 +00:00
parent 56bf1667f8
commit 9a7c786b7f
1 changed files with 20 additions and 13 deletions
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33
src/jrd/Optimizer.cpp
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@ -3462,24 +3462,29 @@ bool OptimizerInnerJoin::cheaperRelationship(IndexRelationship* checkRelationshi
* is cheaper as withRelationship.
*
**************************************/
if (checkRelationship->cost == 0) {
if (checkRelationship->cost == 0)
return true;
}
if (withRelationship->cost == 0) {
if (withRelationship->cost == 0)
return false;
}
const double compareValue = checkRelationship->cost / withRelationship->cost;
if (compareValue >= 0.98 && compareValue <= 1.02)
{
// cost is nearly the same, now check on cardinality
if (checkRelationship->cardinality < withRelationship->cardinality) {
return true;
// cost is nearly the same, now check uniqueness and cardinality
if (checkRelationship->unique == withRelationship->unique)
{
if (checkRelationship->cardinality < withRelationship->cardinality)
return true;
}
else if (checkRelationship->unique)
return true;
else if (withRelationship->unique)
return false;
}
else if (checkRelationship->cost < withRelationship->cost) {
else if (checkRelationship->cost < withRelationship->cost)
return true;
}
return false;
}
@ -3786,20 +3791,22 @@ void OptimizerInnerJoin::getIndexedRelationship(InnerJoinStreamInfo* baseStream,
indexRelationship->stream = testStream->stream;
indexRelationship->unique = candidate->unique;
indexRelationship->cost = candidate->cost;
indexRelationship->cardinality = csb_tail->csb_cardinality * candidate->selectivity;
indexRelationship->cardinality = candidate->unique ?
csb_tail->csb_cardinality : csb_tail->csb_cardinality * candidate->selectivity;
// indexRelationship are kept sorted on cost and unique in the indexRelations array.
// The unique and cheapest indexed relatioships are on the first position.
// The unique and cheapest indexed relationships are on the first position.
size_t index = 0;
for (; index < baseStream->indexedRelationships.getCount(); index++)
{
if (cheaperRelationship(indexRelationship, baseStream->indexedRelationships[index])) {
if (cheaperRelationship(indexRelationship, baseStream->indexedRelationships[index]))
break;
}
}
baseStream->indexedRelationships.insert(index, indexRelationship);
testStream->previousExpectedStreams++;
}
delete candidate;
delete optimizerRetrieval;