ClickHouse/tests/queries/0_stateless/01834_alias_columns_laziness_filimonov.sh

#!/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"