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Fix locking in master_drop_all_shards / master_apply_delete_command

pull/1382/head
Marco Slot 2017-05-03 21:41:12 +02:00
parent 8e2dd3e1f3
commit a8f368fced
4 changed files with 253 additions and 8 deletions
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27
src/backend/distributed/master/master_delete_protocol.c
View File

@ -51,6 +51,7 @@
#include "optimizer/predtest.h"
#include "optimizer/restrictinfo.h"
#include "storage/lock.h"
#include "storage/lmgr.h"
#include "tcop/tcopprot.h"
#include "utils/array.h"
#include "utils/builtins.h"
@ -105,9 +106,7 @@ master_apply_delete_command(PG_FUNCTION_ARGS)
Node *queryTreeNode = NULL;
DeleteStmt *deleteStatement = NULL;
int droppedShardCount = 0;
LOCKTAG lockTag;
bool sessionLock = false;
bool dontWait = false;
LOCKMODE lockMode = 0;
char partitionMethod = 0;
bool failOK = false;
@ -124,7 +123,15 @@ master_apply_delete_command(PG_FUNCTION_ARGS)
schemaName = deleteStatement->relation->schemaname;
relationName = deleteStatement->relation->relname;
relationId = RangeVarGetRelid(deleteStatement->relation, NoLock, failOK);
/*
* We take an exclusive lock while dropping shards to prevent concurrent
* writes. We don't want to block SELECTs, which means queries might fail
* if they access a shard that has just been dropped.
*/
lockMode = ExclusiveLock;
relationId = RangeVarGetRelid(deleteStatement->relation, lockMode, failOK);
/* schema-prefix if it is not specified already */
if (schemaName == NULL)
@ -166,10 +173,6 @@ master_apply_delete_command(PG_FUNCTION_ARGS)
CheckDeleteCriteria(deleteCriteria);
CheckPartitionColumn(relationId, deleteCriteria);
/* acquire lock */
SET_LOCKTAG_ADVISORY(lockTag, MyDatabaseId, relationId, 0, 0);
LockAcquire(&lockTag, ExclusiveLock, sessionLock, dontWait);
shardIntervalList = LoadShardIntervalList(relationId);
/* drop all shards if where clause is not present */
@ -214,6 +217,14 @@ master_drop_all_shards(PG_FUNCTION_ARGS)
CheckTableSchemaNameForDrop(relationId, &schemaName, &relationName);
/*
* master_drop_all_shards is typically called from the DROP TABLE trigger,
* but could be called by a user directly. Make sure we have an
* AccessExlusiveLock to prevent any other commands from running on this table
* concurrently.
*/
LockRelationOid(relationId, AccessExclusiveLock);
shardIntervalList = LoadShardIntervalList(relationId);
droppedShardCount = DropShards(relationId, schemaName, relationName,
shardIntervalList);

162
src/test/regress/expected/isolation_drop_shards.out Normal file
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@ -0,0 +1,162 @@
Parsed test spec with 2 sessions
starting permutation: s1-begin s1-drop-all-shards s2-truncate s1-commit
?column?
1
step s1-begin:
BEGIN;
step s1-drop-all-shards:
SELECT master_drop_all_shards('append_table', 'public', 'append_table');
master_drop_all_shards
16
step s2-truncate:
TRUNCATE append_table;
<waiting ...>
step s1-commit:
COMMIT;
step s2-truncate: <... completed>
starting permutation: s1-begin s1-drop-all-shards s2-apply-delete-command s1-commit
?column?
1
step s1-begin:
BEGIN;
step s1-drop-all-shards:
SELECT master_drop_all_shards('append_table', 'public', 'append_table');
master_drop_all_shards
16
step s2-apply-delete-command:
SELECT master_apply_delete_command('DELETE FROM append_table');
<waiting ...>
step s1-commit:
COMMIT;
step s2-apply-delete-command: <... completed>
master_apply_delete_command
0
starting permutation: s1-begin s1-drop-all-shards s2-drop-all-shards s1-commit
?column?
1
step s1-begin:
BEGIN;
step s1-drop-all-shards:
SELECT master_drop_all_shards('append_table', 'public', 'append_table');
master_drop_all_shards
16
step s2-drop-all-shards:
SELECT master_drop_all_shards('append_table', 'public', 'append_table');
<waiting ...>
step s1-commit:
COMMIT;
step s2-drop-all-shards: <... completed>
master_drop_all_shards
0
starting permutation: s1-begin s1-drop-all-shards s2-select s1-commit
?column?
1
step s1-begin:
BEGIN;
step s1-drop-all-shards:
SELECT master_drop_all_shards('append_table', 'public', 'append_table');
master_drop_all_shards
16
step s2-select:
SELECT * FROM append_table;
<waiting ...>
step s1-commit:
COMMIT;
step s2-select: <... completed>
test_id data
starting permutation: s1-begin s1-apply-delete-command s2-truncate s1-commit
?column?
1
step s1-begin:
BEGIN;
step s1-apply-delete-command:
SELECT master_apply_delete_command('DELETE FROM append_table');
master_apply_delete_command
16
step s2-truncate:
TRUNCATE append_table;
<waiting ...>
step s1-commit:
COMMIT;
step s2-truncate: <... completed>
starting permutation: s1-begin s1-apply-delete-command s2-apply-delete-command s1-commit
?column?
1
step s1-begin:
BEGIN;
step s1-apply-delete-command:
SELECT master_apply_delete_command('DELETE FROM append_table');
master_apply_delete_command
16
step s2-apply-delete-command:
SELECT master_apply_delete_command('DELETE FROM append_table');
<waiting ...>
step s1-commit:
COMMIT;
step s2-apply-delete-command: <... completed>
master_apply_delete_command
0
starting permutation: s1-begin s1-apply-delete-command s2-drop-all-shards s1-commit
?column?
1
step s1-begin:
BEGIN;
step s1-apply-delete-command:
SELECT master_apply_delete_command('DELETE FROM append_table');
master_apply_delete_command
16
step s2-drop-all-shards:
SELECT master_drop_all_shards('append_table', 'public', 'append_table');
<waiting ...>
step s1-commit:
COMMIT;
step s2-drop-all-shards: <... completed>
master_drop_all_shards
0

1
src/test/regress/isolation_schedule
View File

@ -1,3 +1,4 @@
test: isolation_cluster_management
test: isolation_dml_vs_repair
test: isolation_concurrent_dml
test: isolation_drop_shards

71
src/test/regress/specs/isolation_drop_shards.spec Normal file
View File

@ -0,0 +1,71 @@
setup
{
CREATE TABLE append_table (test_id integer NOT NULL, data text);
SELECT create_distributed_table('append_table', 'test_id', 'append');
SELECT 1 FROM (
SELECT min(master_create_empty_shard('append_table')) FROM generate_series(1,16)
) a;
}
teardown
{
DROP TABLE append_table;
}
session "s1"
step "s1-begin"
{
BEGIN;
}
step "s1-apply-delete-command"
{
SELECT master_apply_delete_command('DELETE FROM append_table');
}
step "s1-drop-all-shards"
{
SELECT master_drop_all_shards('append_table', 'public', 'append_table');
}
step "s1-commit"
{
COMMIT;
}
session "s2"
step "s2-truncate"
{
TRUNCATE append_table;
}
step "s2-apply-delete-command"
{
SELECT master_apply_delete_command('DELETE FROM append_table');
}
step "s2-drop-all-shards"
{
SELECT master_drop_all_shards('append_table', 'public', 'append_table');
}
step "s2-select"
{
SELECT * FROM append_table;
}
permutation "s1-begin" "s1-drop-all-shards" "s2-truncate" "s1-commit"
permutation "s1-begin" "s1-drop-all-shards" "s2-apply-delete-command" "s1-commit"
permutation "s1-begin" "s1-drop-all-shards" "s2-drop-all-shards" "s1-commit"
permutation "s1-begin" "s1-drop-all-shards" "s2-select" "s1-commit"
permutation "s1-begin" "s1-apply-delete-command" "s2-truncate" "s1-commit"
permutation "s1-begin" "s1-apply-delete-command" "s2-apply-delete-command" "s1-commit"
permutation "s1-begin" "s1-apply-delete-command" "s2-drop-all-shards" "s1-commit"
# We can't verify master_apply_delete_command + SELECT since it blocks on the
# the workers, but this is not visible on the master, meaning the isolation
# test cannot proceed.