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Add empty reads to cache

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This commit is contained in:
alesapin 2019-04-05 15:57:22 +03:00
parent 7e1975b0c8
commit e8079c8ecd
3 changed files with 7 additions and 7 deletions
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10
dbms/src/Compression/CachedCompressedReadBuffer.cpp
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@ -53,16 +53,16 @@ bool CachedCompressedReadBuffer::nextImpl()
owned_cell->data.resize(size_decompressed + owned_cell->additional_bytes);
decompress(owned_cell->data.data(), size_decompressed, size_compressed_without_checksum);
/// Put data into cache.
cache->set(key, owned_cell);
}
/// Put data into cache.
/// NOTE: Even if we don't read anything (compressed_size == 0)
/// because we can reuse this information and don't reopen file in future
cache->set(key, owned_cell);
}
if (owned_cell->data.size() == 0)
{
owned_cell = nullptr;
return false;
}
working_buffer = Buffer(owned_cell->data.data(), owned_cell->data.data() + owned_cell->data.size() - owned_cell->additional_bytes);

2
dbms/tests/queries/0_stateless/00933_test_fix_extra_seek_on_compressed_cache.reference
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@ -1 +1 @@
36 13
0 36 14

2
dbms/tests/queries/0_stateless/00933_test_fix_extra_seek_on_compressed_cache.sh
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@ -18,7 +18,7 @@ $CLICKHOUSE_CLIENT --use_uncompressed_cache=1 --query_id="test-query-uncompresse
$CLICKHOUSE_CLIENT --query="SYSTEM FLUSH LOGS"
$CLICKHOUSE_CLIENT --query="SELECT ProfileEvents.Values[indexOf(ProfileEvents.Names, 'ReadCompressedBytes')], ProfileEvents.Values[indexOf(ProfileEvents.Names, 'UncompressedCacheHits')] AS hit FROM system.query_log WHERE (query_id = 'test-query-uncompressed-cache') AND (type = 2) ORDER BY event_time DESC LIMIT 1"
$CLICKHOUSE_CLIENT --query="SELECT ProfileEvents.Values[indexOf(ProfileEvents.Names, 'Seek')], ProfileEvents.Values[indexOf(ProfileEvents.Names, 'ReadCompressedBytes')], ProfileEvents.Values[indexOf(ProfileEvents.Names, 'UncompressedCacheHits')] AS hit FROM system.query_log WHERE (query_id = 'test-query-uncompressed-cache') AND (type = 2) ORDER BY event_time DESC LIMIT 1"
$CLICKHOUSE_CLIENT --query="DROP TABLE IF EXISTS test.small_table"