From 779a8f1305c5041cc0523607b21ff688c4a36db2 Mon Sep 17 00:00:00 2001
From: Azat Khuzhin <a3at.mail@gmail.com>
Date: Wed, 21 Sep 2022 03:10:18 +0300
Subject: [PATCH] tests: fix 02340_parts_refcnt_mergetree flakiness (#40998)

---
 .../02340_parts_refcnt_mergetree.sh           | 23 +++++++++++--------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/tests/queries/0_stateless/02340_parts_refcnt_mergetree.sh b/tests/queries/0_stateless/02340_parts_refcnt_mergetree.sh
index 5079977fea0..e8111bf7a03 100755
--- a/tests/queries/0_stateless/02340_parts_refcnt_mergetree.sh
+++ b/tests/queries/0_stateless/02340_parts_refcnt_mergetree.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Tags: no-fasttest
+# Tags: no-fasttest, long
 
 CUR_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
 # shellcheck source=../shell_config.sh
@@ -16,9 +16,10 @@ function check_refcnt_for_table()
     query_id="$table-$(random_str 10)"
 
     # Notes:
-    # - query may sleep 0.1*(200/4)=5 seconds, it is enough to check system.parts
+    # - query may sleep 1*(200/4)=50 seconds maximum, it is enough to check system.parts
     # - "part = 1" condition should prune all parts except first
-    $CLICKHOUSE_CLIENT --format Null --max_block_size 1 --query_id "$query_id" -q "select sleepEachRow(0.1) from $table where part = 1" &
+    # - max_block_size=1 with index_granularity=1 will allow to cancel the query earlier
+    $CLICKHOUSE_CLIENT --format Null --max_threads 1 --max_block_size 1 --query_id "$query_id" -q "select sleepEachRow(1) from $table where part = 1" &
     PID=$!
 
     # wait for query to be started
@@ -30,26 +31,30 @@ function check_refcnt_for_table()
     # however when it starts reading, partition pruning takes place,
     # and it should hold only parts that are required for SELECT
     #
-    # So 2 seconds delay to ensure that it goes the reading stage.
-    sleep 2
+    # But to reach partition prune the function sleepEachRow() will be executed twice,
+    # so 2 seconds for sleepEachRow() and 3 seconds just to ensure that it enters the reading stage.
+    sleep $((2+3))
 
     # NOTE: parts that are used in query will have refcount increased for each range
     $CLICKHOUSE_CLIENT -q "select table, name, refcount from system.parts where database = '$CLICKHOUSE_DATABASE' and table = '$table' and refcount > 1"
 
+    # Kill the query gracefully.
     kill -INT $PID
     wait $PID
 }
 
+# NOTE: index_granularity=1 to cancel ASAP
+
 $CLICKHOUSE_CLIENT -nmq "
     drop table if exists data_02340;
-    create table data_02340 (key Int, part Int) engine=MergeTree() partition by part order by key;
-"
+    create table data_02340 (key Int, part Int) engine=MergeTree() partition by part order by key settings index_granularity=1;
+" || exit 1
 check_refcnt_for_table data_02340
 
 $CLICKHOUSE_CLIENT -nmq "
     drop table if exists data_02340_rep;
-    create table data_02340_rep (key Int, part Int) engine=ReplicatedMergeTree('/clickhouse/$CLICKHOUSE_TEST_ZOOKEEPER_PREFIX', '1') partition by part order by key;
-"
+    create table data_02340_rep (key Int, part Int) engine=ReplicatedMergeTree('/clickhouse/$CLICKHOUSE_TEST_ZOOKEEPER_PREFIX', '1') partition by part order by key settings index_granularity=1;
+" || exit 1
 check_refcnt_for_table data_02340_rep
 
 exit 0