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https://github.com/ClickHouse/ClickHouse.git
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23 lines
1.1 KiB
Bash
Executable File
23 lines
1.1 KiB
Bash
Executable File
#!/usr/bin/env bash
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CUR_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
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# shellcheck source=../shell_config.sh
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. "$CUR_DIR"/../shell_config.sh
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${CLICKHOUSE_CLIENT} --multiquery --query "
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drop table if exists aliases_lazyness;
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create table aliases_lazyness (x UInt32, y ALIAS sleepEachRow(0.1)) Engine=MergeTree ORDER BY x;
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insert into aliases_lazyness(x) select * from numbers(100);
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"
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# In very old ClickHouse versions alias column was calculated for every row.
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# If it works this way, the query will take at least 0.1 * 100 = 10 seconds.
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# If the issue does not exist, the query should call sleepEachRow() "only" 4 times:
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# - from MergeTreeData::getQueryProcessingStageWithAggregateProjection() -> MergeTreeWhereOptimizer -> getBlockWithConstants()
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# - from MergeTreeWhereOptimizer -> getBlockWithConstants()
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# - ReadFromMergeTree::selectRangesToRead() -> getBlockWithConstants()
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# - Pipeline
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${CLICKHOUSE_CLIENT} --profile-events-delay-ms=-1 --print-profile-events --query "SELECT x, y FROM aliases_lazyness WHERE x = 1 FORMAT Null" |& grep -o -e "SleepFunctionMicroseconds.*" -e "SleepFunctionCalls.*"
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${CLICKHOUSE_CLIENT} --query "drop table aliases_lazyness"
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