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Code Issues

Avoid reading/hashing the inner stream(s) if the leader stream is empty

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This commit is contained in:
Dmitry Yemanov 2024-03-20 12:28:46 +03:00
parent 24431065b1
commit fb994b559c
1 changed files with 37 additions and 30 deletions
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67
src/jrd/recsrc/HashJoin.cpp
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@ -318,35 +318,10 @@ void HashJoin::internalOpen(thread_db* tdbb) const
impure->irsb_flags = irsb_open | irsb_mustread;
delete impure->irsb_hash_table;
impure->irsb_hash_table = nullptr;
delete[] impure->irsb_leader_buffer;
MemoryPool& pool = *tdbb->getDefaultPool();
const FB_SIZE_T argCount = m_args.getCount();
impure->irsb_hash_table = FB_NEW_POOL(pool) HashTable(pool, argCount);
impure->irsb_leader_buffer = FB_NEW_POOL(pool) UCHAR[m_leader.totalKeyLength];
UCharBuffer buffer(pool);
for (FB_SIZE_T i = 0; i < argCount; i++)
{
// Read and cache the inner streams. While doing that,
// hash the join condition values and populate hash tables.
m_args[i].buffer->open(tdbb);
ULONG counter = 0;
UCHAR* const keyBuffer = buffer.getBuffer(m_args[i].totalKeyLength, false);
while (m_args[i].buffer->getRecord(tdbb))
{
const ULONG hash = computeHash(tdbb, request, m_args[i], keyBuffer);
impure->irsb_hash_table->put(i, hash, counter++);
}
}
impure->irsb_hash_table->sort();
impure->irsb_leader_buffer = nullptr;
m_leader.source->open(tdbb);
}
@ -363,10 +338,10 @@ void HashJoin::close(thread_db* tdbb) const
impure->irsb_flags &= ~irsb_open;
delete impure->irsb_hash_table;
impure->irsb_hash_table = NULL;
impure->irsb_hash_table = nullptr;
delete[] impure->irsb_leader_buffer;
impure->irsb_leader_buffer = NULL;
impure->irsb_leader_buffer = nullptr;
for (FB_SIZE_T i = 0; i < m_args.getCount(); i++)
m_args[i].buffer->close(tdbb);
@ -394,6 +369,38 @@ bool HashJoin::internalGetRecord(thread_db* tdbb) const
if (!m_leader.source->getRecord(tdbb))
return false;
// We have something to join with, so ensure the hash table is initialized
if (!impure->irsb_hash_table && !impure->irsb_leader_buffer)
{
auto& pool = *tdbb->getDefaultPool();
const auto argCount = m_args.getCount();
impure->irsb_hash_table = FB_NEW_POOL(pool) HashTable(pool, argCount);
impure->irsb_leader_buffer = FB_NEW_POOL(pool) UCHAR[m_leader.totalKeyLength];
UCharBuffer buffer(pool);
for (FB_SIZE_T i = 0; i < argCount; i++)
{
// Read and cache the inner streams. While doing that,
// hash the join condition values and populate hash tables.
m_args[i].buffer->open(tdbb);
ULONG counter = 0;
const auto keyBuffer = buffer.getBuffer(m_args[i].totalKeyLength, false);
while (m_args[i].buffer->getRecord(tdbb))
{
const auto hash = computeHash(tdbb, request, m_args[i], keyBuffer);
impure->irsb_hash_table->put(i, hash, counter++);
}
}
impure->irsb_hash_table->sort();
}
// Compute and hash the comparison keys
impure->irsb_leader_hash =