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Code Issues

Undo some of my prior changes (still WIP). Slightly nicer debug output.

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This commit is contained in:
Dmitry Yemanov 2023-10-15 20:51:37 +03:00
parent 29a40bd872
commit 222c1aff58
1 changed files with 16 additions and 12 deletions
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28
src/jrd/optimizer/InnerJoin.cpp
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@ -189,21 +189,19 @@ void InnerJoin::estimateCost(unsigned position,
joinedStreams[position].selectivity = candidate->selectivity; joinedStreams[position].selectivity = candidate->selectivity;
// Get the stream cardinality // Get the stream cardinality
const auto tail = &csb->csb_rpt[stream->number]; const auto streamCardinality = csb->csb_rpt[stream->number].csb_cardinality;
const auto streamCardinality = tail->csb_cardinality;
auto currentCardinality = streamCardinality * candidate->selectivity; auto currentCardinality = candidate->unique ?
MINIMUM_CARDINALITY : streamCardinality * candidate->selectivity;
auto currentCost = candidate->cost; auto currentCost = candidate->cost;
// Unless an external sort is to be applied, adjust estimated cost and cardinality // Given the "first-rows" mode specified (or implied)
// accordingly to the "first-rows" retrieval (if specified) // and unless an external sort is to be applied afterwards,
// fake the expected cardinality to look as low as possible
// to estimate the cost just for a single row being produced
if ((!sort || candidate->navigated) && optimizer->favorFirstRows()) if ((!sort || candidate->navigated) && optimizer->favorFirstRows())
{
currentCost -= DEFAULT_INDEX_COST;
currentCost /= MAX(currentCardinality, MINIMUM_CARDINALITY);
currentCost += DEFAULT_INDEX_COST;
currentCardinality = MINIMUM_CARDINALITY; currentCardinality = MINIMUM_CARDINALITY;
}
// Calculate the nested loop cost, it's our default option // Calculate the nested loop cost, it's our default option
const auto loopCost = currentCost * cardinality; const auto loopCost = currentCost * cardinality;
@ -687,7 +685,7 @@ InnerJoin::StreamInfo* InnerJoin::getStreamInfo(StreamType stream)
// Dump finally selected stream order // Dump finally selected stream order
void InnerJoin::printBestOrder() const void InnerJoin::printBestOrder() const
{ {
if (bestStreams.isEmpty()) if (bestStreams.getCount() < 2)
return; return;
optimizer->printf(" best order, streams:"); optimizer->printf(" best order, streams:");
@ -742,7 +740,7 @@ void InnerJoin::printFoundOrder(StreamType position,
// Dump finally selected stream order // Dump finally selected stream order
void InnerJoin::printStartOrder() const void InnerJoin::printStartOrder() const
{ {
optimizer->printf("Start join order, streams:"); bool found = false;
const auto end = innerStreams.end(); const auto end = innerStreams.end();
for (auto iter = innerStreams.begin(); iter != end; iter++) for (auto iter = innerStreams.begin(); iter != end; iter++)
@ -750,6 +748,12 @@ void InnerJoin::printStartOrder() const
const auto innerStream = *iter; const auto innerStream = *iter;
if (!innerStream->used) if (!innerStream->used)
{ {
if (!found)
{
optimizer->printf("Start join order, streams:");
found = true;
}
const auto name = optimizer->getStreamName(innerStream->number); const auto name = optimizer->getStreamName(innerStream->number);
optimizer->printf(" %u (%s) base cost (%1.2f)", optimizer->printf(" %u (%s) base cost (%1.2f)",
innerStream->number, name.c_str(), innerStream->baseCost); innerStream->number, name.c_str(), innerStream->baseCost);