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Do not take multi-shard locks on workers

pull/3819/head
Marco Slot 2020-05-04 12:22:23 +02:00
parent 5be8287989
commit 768d8b232c
1 changed files with 6 additions and 1 deletions
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7
src/backend/distributed/executor/distributed_execution_locks.c
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@ -10,6 +10,7 @@
*/ */
#include "distributed/distributed_execution_locks.h" #include "distributed/distributed_execution_locks.h"
#include "distributed/listutils.h" #include "distributed/listutils.h"
#include "distributed/coordinator_protocol.h"
#include "distributed/metadata_cache.h" #include "distributed/metadata_cache.h"
#include "distributed/multi_executor.h" #include "distributed/multi_executor.h"
#include "distributed/multi_partitioning_utils.h" #include "distributed/multi_partitioning_utils.h"
@ -115,9 +116,13 @@ AcquireExecutorMultiShardLocks(List *taskList)
* reduce to a RowExclusiveLock when citus.enable_deadlock_prevention * reduce to a RowExclusiveLock when citus.enable_deadlock_prevention
* is enabled, which lets multi-shard modifications run in parallel as * is enabled, which lets multi-shard modifications run in parallel as
* long as they all disable the GUC. * long as they all disable the GUC.
*
* We also skip taking a heavy-weight lock when running a multi-shard
* commands from workers, since we cannot prevent concurrency across
* workers anyway.
*/ */
if (EnableDeadlockPrevention) if (EnableDeadlockPrevention && IsCoordinator())
{ {
lockMode = ShareUpdateExclusiveLock; lockMode = ShareUpdateExclusiveLock;
} }