@ -15,7 +15,7 @@
* Portions Copyright ( c ) 1994 , Regents of the University of California
*
* IDENTIFICATION
* $ PostgreSQL : pgsql / src / backend / storage / ipc / standby . c , v 1.3 2010 / 01 / 02 16 : 57 : 51 momjian Exp $
* $ PostgreSQL : pgsql / src / backend / storage / ipc / standby . c , v 1.4 2010 / 01 / 14 11 : 08 : 02 sriggs Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -37,6 +37,9 @@ int vacuum_defer_cleanup_age;
static List * RecoveryLockList ;
static void ResolveRecoveryConflictWithVirtualXIDs ( VirtualTransactionId * waitlist ,
char * reason , int cancel_mode ) ;
static void ResolveRecoveryConflictWithLock ( Oid dbOid , Oid relOid ) ;
static void LogCurrentRunningXacts ( RunningTransactions CurrRunningXacts ) ;
static void LogAccessExclusiveLocks ( int nlocks , xl_standby_lock * locks ) ;
@ -162,7 +165,7 @@ WaitExceedsMaxStandbyDelay(void)
*
* We may ask for a specific cancel_mode , typically ERROR or FATAL .
*/
void
static void
ResolveRecoveryConflictWithVirtualXIDs ( VirtualTransactionId * waitlist ,
char * reason , int cancel_mode )
{
@ -272,6 +275,119 @@ ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
}
}
void
ResolveRecoveryConflictWithSnapshot ( TransactionId latestRemovedXid )
{
VirtualTransactionId * backends ;
backends = GetConflictingVirtualXIDs ( latestRemovedXid ,
InvalidOid ,
true ) ;
ResolveRecoveryConflictWithVirtualXIDs ( backends ,
" snapshot conflict " ,
CONFLICT_MODE_ERROR ) ;
}
void
ResolveRecoveryConflictWithTablespace ( Oid tsid )
{
VirtualTransactionId * temp_file_users ;
/*
* Standby users may be currently using this tablespace for
* for their temporary files . We only care about current
* users because temp_tablespace parameter will just ignore
* tablespaces that no longer exist .
*
* Ask everybody to cancel their queries immediately so
* we can ensure no temp files remain and we can remove the
* tablespace . Nuke the entire site from orbit , it ' s the only
* way to be sure .
*
* XXX : We could work out the pids of active backends
* using this tablespace by examining the temp filenames in the
* directory . We would then convert the pids into VirtualXIDs
* before attempting to cancel them .
*
* We don ' t wait for commit because drop tablespace is
* non - transactional .
*/
temp_file_users = GetConflictingVirtualXIDs ( InvalidTransactionId ,
InvalidOid ,
false ) ;
ResolveRecoveryConflictWithVirtualXIDs ( temp_file_users ,
" drop tablespace " ,
CONFLICT_MODE_ERROR ) ;
}
void
ResolveRecoveryConflictWithDatabase ( Oid dbid )
{
/*
* We don ' t do ResolveRecoveryConflictWithVirutalXIDs ( ) here since
* that only waits for transactions and completely idle sessions
* would block us . This is rare enough that we do this as simply
* as possible : no wait , just force them off immediately .
*
* No locking is required here because we already acquired
* AccessExclusiveLock . Anybody trying to connect while we do this
* will block during InitPostgres ( ) and then disconnect when they
* see the database has been removed .
*/
while ( CountDBBackends ( dbid ) > 0 )
{
CancelDBBackends ( dbid ) ;
/*
* Wait awhile for them to die so that we avoid flooding an
* unresponsive backend when system is heavily loaded .
*/
pg_usleep ( 10000 ) ;
}
}
static void
ResolveRecoveryConflictWithLock ( Oid dbOid , Oid relOid )
{
VirtualTransactionId * backends ;
bool report_memory_error = false ;
bool lock_acquired = false ;
int num_attempts = 0 ;
LOCKTAG locktag ;
SET_LOCKTAG_RELATION ( locktag , dbOid , relOid ) ;
/*
* If blowing away everybody with conflicting locks doesn ' t work ,
* after the first two attempts then we just start blowing everybody
* away until it does work . We do this because its likely that we
* either have too many locks and we just can ' t get one at all ,
* or that there are many people crowding for the same table .
* Recovery must win ; the end justifies the means .
*/
while ( ! lock_acquired )
{
if ( + + num_attempts < 3 )
backends = GetLockConflicts ( & locktag , AccessExclusiveLock ) ;
else
{
backends = GetConflictingVirtualXIDs ( InvalidTransactionId ,
InvalidOid ,
true ) ;
report_memory_error = true ;
}
ResolveRecoveryConflictWithVirtualXIDs ( backends ,
" exclusive lock " ,
CONFLICT_MODE_ERROR ) ;
if ( LockAcquireExtended ( & locktag , AccessExclusiveLock , true , true , false )
! = LOCKACQUIRE_NOT_AVAIL )
lock_acquired = true ;
}
}
/*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
* Locking in Recovery Mode
@ -303,8 +419,6 @@ StandbyAcquireAccessExclusiveLock(TransactionId xid, Oid dbOid, Oid relOid)
{
xl_standby_lock * newlock ;
LOCKTAG locktag ;
bool report_memory_error = false ;
int num_attempts = 0 ;
/* Already processed? */
if ( TransactionIdDidCommit ( xid ) | | TransactionIdDidAbort ( xid ) )
@ -323,41 +437,13 @@ StandbyAcquireAccessExclusiveLock(TransactionId xid, Oid dbOid, Oid relOid)
RecoveryLockList = lappend ( RecoveryLockList , newlock ) ;
/*
* Attempt to acquire the lock as requested .
* Attempt to acquire the lock as requested , if not resolve conflict
*/
SET_LOCKTAG_RELATION ( locktag , newlock - > dbOid , newlock - > relOid ) ;
/*
* Wait for lock to clear or kill anyone in our way .
*/
while ( LockAcquireExtended ( & locktag , AccessExclusiveLock ,
true , true , report_memory_error )
if ( LockAcquireExtended ( & locktag , AccessExclusiveLock , true , true , false )
= = LOCKACQUIRE_NOT_AVAIL )
{
VirtualTransactionId * backends ;
/*
* If blowing away everybody with conflicting locks doesn ' t work ,
* after the first two attempts then we just start blowing everybody
* away until it does work . We do this because its likely that we
* either have too many locks and we just can ' t get one at all ,
* or that there are many people crowding for the same table .
* Recovery must win ; the end justifies the means .
*/
if ( + + num_attempts < 3 )
backends = GetLockConflicts ( & locktag , AccessExclusiveLock ) ;
else
{
backends = GetConflictingVirtualXIDs ( InvalidTransactionId ,
InvalidOid ,
true ) ;
report_memory_error = true ;
}
ResolveRecoveryConflictWithVirtualXIDs ( backends ,
" exclusive lock " ,
CONFLICT_MODE_ERROR ) ;
}
ResolveRecoveryConflictWithLock ( newlock - > dbOid , newlock - > relOid ) ;
}
static void
Simon Riggs
16 years ago