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Clean up backend-exit-time cleanup behavior. Use on_shmem_exit callbacks

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to ensure that we have released buffer refcounts and so forth, rather than
putting ad-hoc operations before (some of the calls to) proc_exit.  Add
commentary to discourage future hackers from repeating that mistake.
This commit is contained in:
Tom Lane
2000-12-18 00:44:50 +00:00
parent 8c8ed4f456
commit a626b78c89
14 changed files with 255 additions and 139 deletions
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109
src/backend/utils/init/postinit.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.75 2000/12/14 23:51:35 wieck Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/init/postinit.c,v 1.76 2000/12/18 00:44:48 tgl Exp $
*
*
*-------------------------------------------------------------------------
@ -28,6 +28,7 @@
#include "access/heapam.h"
#include "catalog/catname.h"
#include "catalog/pg_database.h"
#include "commands/trigger.h"
#include "miscadmin.h"
#include "storage/backendid.h"
#include "storage/proc.h"
@ -37,6 +38,7 @@
#include "utils/portal.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
#include "utils/temprel.h"
#ifdef MULTIBYTE
#include "mb/pg_wchar.h"
@ -44,6 +46,9 @@
static void ReverifyMyDatabase(const char *name);
static void InitCommunication(void);
static void ShutdownPostgres(void);
int lockingOff = 0; /* backend -L switch */
/*** InitPostgres support ***/
@ -115,12 +120,8 @@ ReverifyMyDatabase(const char *name)
*/
dbform = (Form_pg_database) GETSTRUCT(tup);
if (! dbform->datallowconn)
{
heap_endscan(pgdbscan);
heap_close(pgdbrel, AccessShareLock);
elog(FATAL, "Database \"%s\" is not currently accepting connections",
name);
}
/*
* OK, we're golden. Only other to-do item is to save the MULTIBYTE
@ -163,6 +164,28 @@ InitCommunication(void)
}
/*
* Early initialization of a backend (either standalone or under postmaster).
* This happens even before InitPostgres.
*/
void
BaseInit(void)
{
/*
* Attach to shared memory and semaphores, and initialize our
* input/output/debugging file descriptors.
*/
InitCommunication();
DebugFileOpen();
/* Do local initialization of storage and buffer managers */
smgrinit();
InitBufferPoolAccess();
InitLocalBuffer();
EnablePortalManager(); /* memory for portal/transaction stuff */
}
/* --------------------------------
* InitPostgres
@ -172,16 +195,13 @@ InitCommunication(void)
* Be very careful with the order of calls in the InitPostgres function.
* --------------------------------
*/
int lockingOff = 0; /* backend -L switch */
/*
*/
void
InitPostgres(const char *dbname, const char *username)
{
bool bootstrap = IsBootstrapProcessingMode();
SetDatabaseName(dbname);
/* ----------------
* initialize the database id used for system caches and lock tables
* ----------------
@ -299,6 +319,12 @@ InitPostgres(const char *dbname, const char *username)
*/
InitCatalogCache();
/*
* Initialize the deferred trigger manager --- must happen before
* first transaction start.
*/
DeferredTriggerInit();
/* start a new transaction here before access to db */
if (!bootstrap)
StartTransactionCommand();
@ -322,27 +348,62 @@ InitPostgres(const char *dbname, const char *username)
/*
* Unless we are bootstrapping, double-check that InitMyDatabaseInfo()
* got a correct result. We can't do this until essentially all the
* infrastructure is up, so just do it at the end.
* got a correct result. We can't do this until all the database-access
* infrastructure is up.
*/
if (!bootstrap)
ReverifyMyDatabase(dbname);
#ifdef MULTIBYTE
/* set default client encoding --- uses info from ReverifyMyDatabase */
set_default_client_encoding();
#endif
/*
* Set up process-exit callbacks to remove temp relations and then
* do pre-shutdown cleanup. This should be last because we want
* shmem_exit to call these routines before the exit callbacks that
* are registered by buffer manager, lock manager, etc. We need
* to run this code before we close down database access!
*/
on_shmem_exit(ShutdownPostgres, 0);
/* because callbacks are called in reverse order, this gets done first: */
on_shmem_exit(remove_all_temp_relations, 0);
/* close the transaction we started above */
if (!bootstrap)
CommitTransactionCommand();
}
void
BaseInit(void)
/*
* Backend-shutdown callback. Do cleanup that we want to be sure happens
* before all the supporting modules begin to nail their doors shut via
* their own callbacks. Note that because this has to be registered very
* late in startup, it will not get called if we suffer a failure *during*
* startup.
*
* User-level cleanup, such as temp-relation removal and UNLISTEN, happens
* via separate callbacks that execute before this one. We don't combine the
* callbacks because we still want this one to happen if the user-level
* cleanup fails.
*/
static void
ShutdownPostgres(void)
{
/*
* Attach to shared memory and semaphores, and initialize our
* input/output/debugging file descriptors.
* These operations are really just a minimal subset of AbortTransaction().
* We don't want to do any inessential cleanup, since that just raises
* the odds of failure --- but there's some stuff we need to do.
*
* Release any spinlocks that we may hold. This is a kluge to improve
* the odds that we won't get into a self-made stuck spinlock scenario
* while trying to shut down.
*/
InitCommunication();
DebugFileOpen();
smgrinit();
EnablePortalManager(); /* memory for portal/transaction stuff */
/* initialize the local buffer manager */
InitLocalBuffer();
ProcReleaseSpins(NULL);
/*
* In case a transaction is open, delete any files it created. This
* has to happen before bufmgr shutdown, so having smgr register a
* callback for it wouldn't work.
*/
smgrDoPendingDeletes(false); /* delete as though aborting xact */
}