@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $ PostgreSQL : pgsql / src / backend / storage / lmgr / proc . c , v 1.213 2010 / 01 / 16 10 : 05 : 50 sriggs Exp $
* $ PostgreSQL : pgsql / src / backend / storage / lmgr / proc . c , v 1.214 2010 / 01 / 23 16 : 37 : 12 sriggs Exp $
*
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
*/
@ -73,6 +73,7 @@ NON_EXEC_STATIC PGPROC *AuxiliaryProcs = NULL;
static LOCALLOCK * lockAwaited = NULL ;
/* Mark these volatile because they can be changed by signal handler */
static volatile bool standby_timeout_active = false ;
static volatile bool statement_timeout_active = false ;
static volatile bool deadlock_timeout_active = false ;
static volatile DeadLockState deadlock_state = DS_NOT_YET_CHECKED ;
@ -89,6 +90,7 @@ static void RemoveProcFromArray(int code, Datum arg);
static void ProcKill ( int code , Datum arg ) ;
static void AuxiliaryProcKill ( int code , Datum arg ) ;
static bool CheckStatementTimeout ( void ) ;
static bool CheckStandbyTimeout ( void ) ;
/*
@ -107,6 +109,8 @@ ProcGlobalShmemSize(void)
size = add_size ( size , mul_size ( MaxBackends , sizeof ( PGPROC ) ) ) ;
/* ProcStructLock */
size = add_size ( size , sizeof ( slock_t ) ) ;
/* startupBufferPinWaitBufId */
size = add_size ( size , sizeof ( NBuffers ) ) ;
return size ;
}
@ -487,10 +491,43 @@ PublishStartupProcessInformation(void)
procglobal - > startupProc = MyProc ;
procglobal - > startupProcPid = MyProcPid ;
procglobal - > startupBufferPinWaitBufId = 0 ;
SpinLockRelease ( ProcStructLock ) ;
}
/*
* Used from bufgr to share the value of the buffer that Startup waits on ,
* or to reset the value to " not waiting " ( - 1 ) . This allows processing
* of recovery conflicts for buffer pins . Set is made before backends look
* at this value , so locking not required , especially since the set is
* an atomic integer set operation .
*/
void
SetStartupBufferPinWaitBufId ( int bufid )
{
/* use volatile pointer to prevent code rearrangement */
volatile PROC_HDR * procglobal = ProcGlobal ;
procglobal - > startupBufferPinWaitBufId = bufid ;
}
/*
* Used by backends when they receive a request to check for buffer pin waits .
*/
int
GetStartupBufferPinWaitBufId ( void )
{
int bufid ;
/* use volatile pointer to prevent code rearrangement */
volatile PROC_HDR * procglobal = ProcGlobal ;
bufid = procglobal - > startupBufferPinWaitBufId ;
return bufid ;
}
/*
* Check whether there are at least N free PGPROC objects .
*
@ -1542,7 +1579,7 @@ CheckStatementTimeout(void)
/*
* Signal handler for SIGALRM
* Signal handler for SIGALRM for normal user backends
*
* Process deadlock check and / or statement timeout check , as needed .
* To avoid various edge cases , we must be careful to do nothing
@ -1565,3 +1602,112 @@ handle_sig_alarm(SIGNAL_ARGS)
errno = save_errno ;
}
/*
* Signal handler for SIGALRM in Startup process
*
* To avoid various edge cases , we must be careful to do nothing
* when there is nothing to be done . We also need to be able to
* reschedule the timer interrupt if called before end of statement .
*/
bool
enable_standby_sig_alarm ( long delay_s , int delay_us , TimestampTz fin_time )
{
struct itimerval timeval ;
Assert ( delay_s > = 0 & & delay_us > = 0 ) ;
statement_fin_time = fin_time ;
standby_timeout_active = true ;
MemSet ( & timeval , 0 , sizeof ( struct itimerval ) ) ;
timeval . it_value . tv_sec = delay_s ;
timeval . it_value . tv_usec = delay_us ;
if ( setitimer ( ITIMER_REAL , & timeval , NULL ) )
return false ;
return true ;
}
bool
disable_standby_sig_alarm ( void )
{
/*
* Always disable the interrupt if it is active ; this avoids being
* interrupted by the signal handler and thereby possibly getting
* confused .
*
* We will re - enable the interrupt if necessary in CheckStandbyTimeout .
*/
if ( standby_timeout_active )
{
struct itimerval timeval ;
MemSet ( & timeval , 0 , sizeof ( struct itimerval ) ) ;
if ( setitimer ( ITIMER_REAL , & timeval , NULL ) )
{
standby_timeout_active = false ;
return false ;
}
}
standby_timeout_active = false ;
return true ;
}
/*
* CheckStandbyTimeout ( ) runs unconditionally in the Startup process
* SIGALRM handler . Timers will only be set when InHotStandby .
* We simply ignore any signals unless the timer has been set .
*/
static bool
CheckStandbyTimeout ( void )
{
TimestampTz now ;
standby_timeout_active = false ;
now = GetCurrentTimestamp ( ) ;
if ( now > = statement_fin_time )
SendRecoveryConflictWithBufferPin ( ) ;
else
{
/* Not time yet, so (re)schedule the interrupt */
long secs ;
int usecs ;
struct itimerval timeval ;
TimestampDifference ( now , statement_fin_time ,
& secs , & usecs ) ;
/*
* It ' s possible that the difference is less than a microsecond ;
* ensure we don ' t cancel , rather than set , the interrupt .
*/
if ( secs = = 0 & & usecs = = 0 )
usecs = 1 ;
standby_timeout_active = true ;
MemSet ( & timeval , 0 , sizeof ( struct itimerval ) ) ;
timeval . it_value . tv_sec = secs ;
timeval . it_value . tv_usec = usecs ;
if ( setitimer ( ITIMER_REAL , & timeval , NULL ) )
return false ;
}
return true ;
}
void
handle_standby_sig_alarm ( SIGNAL_ARGS )
{
int save_errno = errno ;
if ( standby_timeout_active )
( void ) CheckStandbyTimeout ( ) ;
errno = save_errno ;
}
Simon Riggs
16 years ago