#!/usr/bin/env bash CUR_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd) # shellcheck source=../shell_config.sh . "$CUR_DIR"/../shell_config.sh ${CLICKHOUSE_CLIENT} --multiquery --query " drop table if exists aliases_lazyness; create table aliases_lazyness (x UInt32, y ALIAS sleepEachRow(0.1)) Engine=MergeTree ORDER BY x; insert into aliases_lazyness(x) select * from numbers(100); " # In very old ClickHouse versions alias column was calculated for every row. # If it works this way, the query will take at least 0.1 * 100 = 10 seconds. # If the issue does not exist, the query should call sleepEachRow() "only" 4 times: # - from MergeTreeData::getQueryProcessingStageWithAggregateProjection() -> MergeTreeWhereOptimizer -> getBlockWithConstants() # - from MergeTreeWhereOptimizer -> getBlockWithConstants() # - ReadFromMergeTree::selectRangesToRead() -> getBlockWithConstants() # - Pipeline ${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.*" ${CLICKHOUSE_CLIENT} --query "drop table aliases_lazyness"