external
/
citus
mirror of https://github.com/citusdata/citus.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Take AccessShareLock on the extension prior to running deadlock detection

pull/1584/head
Andres Freund 2017-08-17 01:35:09 -07:00 committed by Marco Slot
parent 0ddcd726c9
commit b936bde936
1 changed files with 43 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
src/backend/distributed/utils/maintenanced.c
View File

@ -21,6 +21,8 @@
#include "pgstat.h"
#include "access/xact.h"
#include "catalog/pg_extension.h"
#include "commands/extension.h"
#include "libpq/pqsignal.h"
#include "distributed/distributed_deadlock_detection.h"
#include "distributed/maintenanced.h"
@ -29,6 +31,7 @@
#include "storage/ipc.h"
#include "storage/proc.h"
#include "storage/latch.h"
#include "storage/lmgr.h"
#include "storage/lwlock.h"
#include "tcop/tcopprot.h"
@ -85,6 +88,8 @@ static void MaintenanceDaemonSigHupHandler(SIGNAL_ARGS);
static size_t MaintenanceDaemonShmemSize(void);
static void MaintenanceDaemonShmemInit(void);
static void MaintenanceDaemonErrorContext(void *arg);
static bool LockCitusExtension(void);
/*
* InitializeMaintenanceDaemon, called at server start, is responsible for
@ -272,11 +277,12 @@ CitusMaintenanceDaemonMain(Datum main_arg)
{
StartTransactionCommand();
/*
* We don't want to run the deadlock checks if there exists
* any version mistmatch.
*/
if (CheckCitusVersion(DEBUG1))
if (!LockCitusExtension())
{
ereport(DEBUG1, (errmsg("could not lock the citus extension, "
"skipping deadlock detection")));
}
else if (CheckCitusVersion(DEBUG1) && CitusHasBeenLoaded())
{
foundDeadlock = CheckForDistributedDeadlocks();
}
@ -472,3 +478,35 @@ MaintenanceDaemonErrorContext(void *arg)
errcontext("Citus maintenance daemon for database %u user %u",
myDbData->databaseOid, myDbData->userOid);
}
/*
* LockCitusExtension acquires a lock on the Citus extension or returns
* false if the extension does not exist or is being dropped.
*/
static bool
LockCitusExtension(void)
{
Oid recheckExtensionOid = InvalidOid;
Oid extensionOid = get_extension_oid("citus", true);
if (extensionOid == InvalidOid)
{
/* citus extension does not exist */
return false;
}
LockDatabaseObject(ExtensionRelationId, extensionOid, 0, AccessShareLock);
/*
* The extension may have been dropped and possibly recreated prior to
* obtaining a lock. Check whether we still get the expected OID.
*/
recheckExtensionOid = get_extension_oid("citus", true);
if (recheckExtensionOid != extensionOid)
{
return false;
}
return true;
}