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Merge pull request #2494 from citusdata/notsolocky 

Relax multi-shard modify locks when enable_deadlock_prevention is disabled
pull/2493/head
Marco Slot 2018-11-28 15:21:44 +01:00 committed by GitHub
parent e8f3b32b64 0393910c65
commit 435a036328
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GPG Key ID: 4AEE18F83AFDEB23
6 changed files with 112 additions and 28 deletions
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14
src/backend/distributed/executor/multi_router_executor.c
View File

@ -369,9 +369,21 @@ AcquireExecutorMultiShardLocks(List *taskList)
* In either case, ShareUpdateExclusive has the desired effect, since
* it conflicts with itself and ExclusiveLock (taken by non-commutative
* writes).
*
* However, some users find this too restrictive, so we allow them to
* reduce to a RowExclusiveLock when citus.enable_deadlock_prevention
* is enabled, which lets multi-shard modifications run in parallel as
* long as they all disable the GUC.
*/
lockMode = ShareUpdateExclusiveLock;
if (EnableDeadlockPrevention)
{
lockMode = ShareUpdateExclusiveLock;
}
else
{
lockMode = RowExclusiveLock;
}
}
else
{

14
src/backend/distributed/shared_library_init.c
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@ -565,15 +565,17 @@ RegisterCitusConfigVariables(void)
DefineCustomBoolVariable(
"citus.enable_deadlock_prevention",
gettext_noop("Prevents transactions from expanding to multiple nodes"),
gettext_noop("When enabled, consecutive DML statements that write to "
"shards on different nodes are prevented to avoid creating "
"undetectable distributed deadlocks when performed "
"concurrently."),
gettext_noop("Avoids deadlocks by preventing concurrent multi-shard commands"),
gettext_noop("Multi-shard modifications such as UPDATE, DELETE, and "
"INSERT...SELECT are typically executed in parallel. If multiple "
"such commands run concurrently and affect the same rows, then "
"they are likely to deadlock. When enabled, this flag prevents "
"multi-shard modifications from running concurrently when they "
"affect the same shards in order to prevent deadlocks."),
&EnableDeadlockPrevention,
true,
PGC_USERSET,
GUC_NO_SHOW_ALL,
0,
NULL, NULL, NULL);
DefineCustomBoolVariable(

20
src/test/regress/expected/isolation_citus_dist_activity.out
View File

@ -30,16 +30,16 @@ step s3-view-worker:
query query_hostname query_hostport master_query_host_namemaster_query_host_portstate wait_event_typewait_event usename datname
SELECT worker_apply_shard_ddl_command (105833, 'public', '
SELECT worker_apply_shard_ddl_command (105961, 'public', '
ALTER TABLE test_table ADD COLUMN x INT;
')localhost 57638 coordinator_host57636 idle in transactionClient ClientRead postgres regression
SELECT worker_apply_shard_ddl_command (105832, 'public', '
SELECT worker_apply_shard_ddl_command (105960, 'public', '
ALTER TABLE test_table ADD COLUMN x INT;
')localhost 57637 coordinator_host57636 idle in transactionClient ClientRead postgres regression
SELECT worker_apply_shard_ddl_command (105831, 'public', '
SELECT worker_apply_shard_ddl_command (105959, 'public', '
ALTER TABLE test_table ADD COLUMN x INT;
')localhost 57638 coordinator_host57636 idle in transactionClient ClientRead postgres regression
SELECT worker_apply_shard_ddl_command (105830, 'public', '
SELECT worker_apply_shard_ddl_command (105958, 'public', '
ALTER TABLE test_table ADD COLUMN x INT;
')localhost 57637 coordinator_host57636 idle in transactionClient ClientRead postgres regression
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57638 0 idle Client ClientRead postgres regression
@ -86,7 +86,7 @@ query query_hostname query_hostport master_query_host_namemaster_query_
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57638 0 idle Client ClientRead postgres regression
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57637 0 idle Client ClientRead postgres regression
INSERT INTO public.test_table_105836 (column1, column2) VALUES (100, 100)localhost 57637 coordinator_host57636 idle in transactionClient ClientRead postgres regression
INSERT INTO public.test_table_105964 (column1, column2) VALUES (100, 100)localhost 57637 coordinator_host57636 idle in transactionClient ClientRead postgres regression
step s2-rollback:
ROLLBACK;
@ -132,10 +132,10 @@ query query_hostname query_hostport master_query_host_namemaster_query_
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57638 0 idle Client ClientRead postgres regression
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57637 0 idle Client ClientRead postgres regression
COPY (SELECT count(*) AS count FROM test_table_105841 test_table WHERE true) TO STDOUTlocalhost 57638 coordinator_host57636 idle in transactionClient ClientRead postgres regression
COPY (SELECT count(*) AS count FROM test_table_105840 test_table WHERE true) TO STDOUTlocalhost 57637 coordinator_host57636 idle in transactionClient ClientRead postgres regression
COPY (SELECT count(*) AS count FROM test_table_105839 test_table WHERE true) TO STDOUTlocalhost 57638 coordinator_host57636 idle in transactionClient ClientRead postgres regression
COPY (SELECT count(*) AS count FROM test_table_105838 test_table WHERE true) TO STDOUTlocalhost 57637 coordinator_host57636 idle in transactionClient ClientRead postgres regression
COPY (SELECT count(*) AS count FROM test_table_105969 test_table WHERE true) TO STDOUTlocalhost 57638 coordinator_host57636 idle in transactionClient ClientRead postgres regression
COPY (SELECT count(*) AS count FROM test_table_105968 test_table WHERE true) TO STDOUTlocalhost 57637 coordinator_host57636 idle in transactionClient ClientRead postgres regression
COPY (SELECT count(*) AS count FROM test_table_105967 test_table WHERE true) TO STDOUTlocalhost 57638 coordinator_host57636 idle in transactionClient ClientRead postgres regression
COPY (SELECT count(*) AS count FROM test_table_105966 test_table WHERE true) TO STDOUTlocalhost 57637 coordinator_host57636 idle in transactionClient ClientRead postgres regression
step s2-rollback:
ROLLBACK;
@ -181,7 +181,7 @@ query query_hostname query_hostport master_query_host_namemaster_query_
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57638 0 idle Client ClientRead postgres regression
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57637 0 idle Client ClientRead postgres regression
SELECT count(*) AS count FROM public.test_table_105843 test_table WHERE (column1 OPERATOR(pg_catalog.=) 55)localhost 57638 0 idle Client ClientRead postgres regression
SELECT count(*) AS count FROM public.test_table_105971 test_table WHERE (column1 OPERATOR(pg_catalog.=) 55)localhost 57638 0 idle Client ClientRead postgres regression
COMMIT localhost 57637 0 idle Client ClientRead postgres regression
step s2-rollback:
ROLLBACK;

20
src/test/regress/expected/isolation_citus_dist_activity_0.out
View File

@ -30,16 +30,16 @@ step s3-view-worker:
query query_hostname query_hostport master_query_host_namemaster_query_host_portstate wait_event_typewait_event usename datname
SELECT worker_apply_shard_ddl_command (105297, 'public', '
SELECT worker_apply_shard_ddl_command (105425, 'public', '
ALTER TABLE test_table ADD COLUMN x INT;
')localhost 57638 coordinator_host57636 idle in transaction postgres regression
SELECT worker_apply_shard_ddl_command (105296, 'public', '
SELECT worker_apply_shard_ddl_command (105424, 'public', '
ALTER TABLE test_table ADD COLUMN x INT;
')localhost 57637 coordinator_host57636 idle in transaction postgres regression
SELECT worker_apply_shard_ddl_command (105295, 'public', '
SELECT worker_apply_shard_ddl_command (105423, 'public', '
ALTER TABLE test_table ADD COLUMN x INT;
')localhost 57638 coordinator_host57636 idle in transaction postgres regression
SELECT worker_apply_shard_ddl_command (105294, 'public', '
SELECT worker_apply_shard_ddl_command (105422, 'public', '
ALTER TABLE test_table ADD COLUMN x INT;
')localhost 57637 coordinator_host57636 idle in transaction postgres regression
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57638 0 idle postgres regression
@ -86,7 +86,7 @@ query query_hostname query_hostport master_query_host_namemaster_query_
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57638 0 idle postgres regression
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57637 0 idle postgres regression
INSERT INTO public.test_table_105300 (column1, column2) VALUES (100, 100)localhost 57637 coordinator_host57636 idle in transaction postgres regression
INSERT INTO public.test_table_105428 (column1, column2) VALUES (100, 100)localhost 57637 coordinator_host57636 idle in transaction postgres regression
step s2-rollback:
ROLLBACK;
@ -132,10 +132,10 @@ query query_hostname query_hostport master_query_host_namemaster_query_
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57638 0 idle postgres regression
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57637 0 idle postgres regression
COPY (SELECT count(*) AS count FROM test_table_105305 test_table WHERE true) TO STDOUTlocalhost 57638 coordinator_host57636 idle in transaction postgres regression
COPY (SELECT count(*) AS count FROM test_table_105304 test_table WHERE true) TO STDOUTlocalhost 57637 coordinator_host57636 idle in transaction postgres regression
COPY (SELECT count(*) AS count FROM test_table_105303 test_table WHERE true) TO STDOUTlocalhost 57638 coordinator_host57636 idle in transaction postgres regression
COPY (SELECT count(*) AS count FROM test_table_105302 test_table WHERE true) TO STDOUTlocalhost 57637 coordinator_host57636 idle in transaction postgres regression
COPY (SELECT count(*) AS count FROM test_table_105433 test_table WHERE true) TO STDOUTlocalhost 57638 coordinator_host57636 idle in transaction postgres regression
COPY (SELECT count(*) AS count FROM test_table_105432 test_table WHERE true) TO STDOUTlocalhost 57637 coordinator_host57636 idle in transaction postgres regression
COPY (SELECT count(*) AS count FROM test_table_105431 test_table WHERE true) TO STDOUTlocalhost 57638 coordinator_host57636 idle in transaction postgres regression
COPY (SELECT count(*) AS count FROM test_table_105430 test_table WHERE true) TO STDOUTlocalhost 57637 coordinator_host57636 idle in transaction postgres regression
step s2-rollback:
ROLLBACK;
@ -181,7 +181,7 @@ query query_hostname query_hostport master_query_host_namemaster_query_
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57638 0 idle postgres regression
SELECT gid FROM pg_prepared_xacts WHERE gid LIKE 'citus\_0\_%'localhost 57637 0 idle postgres regression
SELECT count(*) AS count FROM public.test_table_105307 test_table WHERE (column1 OPERATOR(pg_catalog.=) 55)localhost 57638 0 idle postgres regression
SELECT count(*) AS count FROM public.test_table_105435 test_table WHERE (column1 OPERATOR(pg_catalog.=) 55)localhost 57638 0 idle postgres regression
COMMIT localhost 57637 0 idle postgres regression
step s2-rollback:
ROLLBACK;

47
src/test/regress/expected/isolation_multi_shard_modify_vs_all.out
View File

@ -62,6 +62,53 @@ step s2-commit:
COMMIT;
starting permutation: s1-begin s1-update_even_concurrently s2-begin s2-update_odd_concurrently s1-commit s2-commit
step s1-begin:
BEGIN;
step s1-update_even_concurrently:
SET citus.enable_deadlock_prevention TO off;
UPDATE users_test_table SET value_1 = 3 WHERE user_id % 2 = 0;
SET citus.enable_deadlock_prevention TO on;
step s2-begin:
BEGIN;
step s2-update_odd_concurrently:
SET citus.enable_deadlock_prevention = off;
UPDATE users_test_table SET value_1 = 3 WHERE user_id % 2 = 1;
SET citus.enable_deadlock_prevention TO on;
step s1-commit:
COMMIT;
step s2-commit:
COMMIT;
starting permutation: s1-begin s1-update_even_concurrently s2-begin s2-update_value_1_of_4_or_6_to_4 s1-commit s2-commit
step s1-begin:
BEGIN;
step s1-update_even_concurrently:
SET citus.enable_deadlock_prevention TO off;
UPDATE users_test_table SET value_1 = 3 WHERE user_id % 2 = 0;
SET citus.enable_deadlock_prevention TO on;
step s2-begin:
BEGIN;
step s2-update_value_1_of_4_or_6_to_4:
UPDATE users_test_table SET value_1 = 4 WHERE user_id = 4 or user_id = 6;
<waiting ...>
step s1-commit:
COMMIT;
step s2-update_value_1_of_4_or_6_to_4: <... completed>
step s2-commit:
COMMIT;
starting permutation: s1-begin s1-update_value_1_of_1_or_3_to_5 s2-begin s2-update_value_1_of_4_or_6_to_4 s1-commit s2-commit s2-select
step s1-begin:
BEGIN;

23
src/test/regress/specs/isolation_multi_shard_modify_vs_all.spec
View File

@ -55,6 +55,13 @@ step "s1-update_all_value_1"
UPDATE users_test_table SET value_1 = 3;
}
step "s1-update_even_concurrently"
{
SET citus.enable_deadlock_prevention TO off;
UPDATE users_test_table SET value_1 = 3 WHERE user_id % 2 = 0;
SET citus.enable_deadlock_prevention TO on;
}
step "s1-update_value_1_of_1_or_3_to_5"
{
UPDATE users_test_table SET value_1 = 5 WHERE user_id = 1 or user_id = 3;
@ -107,6 +114,13 @@ step "s2-update_all_value_1"
UPDATE users_test_table SET value_1 = 6;
}
step "s2-update_odd_concurrently"
{
SET citus.enable_deadlock_prevention = off;
UPDATE users_test_table SET value_1 = 3 WHERE user_id % 2 = 1;
SET citus.enable_deadlock_prevention TO on;
}
step "s2-update_value_1_of_1_or_3_to_8"
{
UPDATE users_test_table SET value_1 = 8 WHERE user_id = 1 or user_id = 3;
@ -125,10 +139,19 @@ step "s2-commit"
# test with parallel connections
permutation "s1-begin" "s1-update_all_value_1" "s2-begin" "s2-select" "s1-commit" "s2-select" "s2-commit"
permutation "s1-begin" "s1-update_all_value_1" "s2-begin" "s2-update_all_value_1" "s1-commit" "s2-commit"
# test without deadlock prevention (first does not conflict, second does)
permutation "s1-begin" "s1-update_even_concurrently" "s2-begin" "s2-update_odd_concurrently" "s1-commit" "s2-commit"
permutation "s1-begin" "s1-update_even_concurrently" "s2-begin" "s2-update_value_1_of_4_or_6_to_4" "s1-commit" "s2-commit"
# test with shard pruning (should not conflict)
permutation "s1-begin" "s1-update_value_1_of_1_or_3_to_5" "s2-begin" "s2-update_value_1_of_4_or_6_to_4" "s1-commit" "s2-commit" "s2-select"
permutation "s1-begin" "s1-update_value_1_of_1_or_3_to_5" "s2-begin" "s2-update_value_1_of_1_or_3_to_8" "s1-commit" "s2-commit" "s2-select"
# test with inserts
permutation "s1-begin" "s1-update_all_value_1" "s2-begin" "s2-insert-to-table" "s1-commit" "s2-commit" "s2-select"
permutation "s1-begin" "s1-update_all_value_1" "s2-begin" "s2-insert-into-select" "s1-commit" "s2-commit" "s2-select"
# multi-shard update affecting the same rows
permutation "s1-begin" "s2-begin" "s1-update_value_1_of_1_or_3_to_5" "s2-update_value_1_of_1_or_3_to_8" "s1-commit" "s2-commit"
# multi-shard update affecting the different rows