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process startup: Always call Init[Auxiliary]Process() before BaseInit().

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For EXEC_BACKEND InitProcess()/InitAuxiliaryProcess() needs to have been
called well before we call BaseInit(), as SubPostmasterMain() needs LWLocks to
work. Having the order of initialization differ between platforms makes it
unnecessarily hard to understand the system and to add initialization points
for new subsystems without a lot of duplication.

To be able to change the order, BaseInit() cannot trigger
CreateSharedMemoryAndSemaphores() anymore - obviously that needs to have
happened before we can call InitProcess(). It seems cleaner to create shared
memory explicitly in single user/bootstrap mode anyway.

After this change the separation of bufmgr initialization into
InitBufferPoolAccess() / InitBufferPoolBackend() is not meaningful anymore so
the latter is removed.

Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
This commit is contained in:
Andres Freund
2021-08-05 14:37:09 -07:00
parent 0de13bbc47
commit b406478b87
8 changed files with 39 additions and 83 deletions
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23
src/backend/storage/buffer/bufmgr.c
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@ -2582,11 +2582,6 @@ AtEOXact_Buffers(bool isCommit)
* This is called during backend startup (whether standalone or under the
* postmaster). It sets up for this backend's access to the already-existing
* buffer pool.
*
* NB: this is called before InitProcess(), so we do not have a PGPROC and
* cannot do LWLockAcquire; hence we can't actually access stuff in
* shared memory yet. We are only initializing local data here.
* (See also InitBufferPoolBackend)
*/
void
InitBufferPoolAccess(void)
@ -2600,20 +2595,12 @@ InitBufferPoolAccess(void)
PrivateRefCountHash = hash_create("PrivateRefCount", 100, &hash_ctl,
HASH_ELEM | HASH_BLOBS);
}
/*
* InitBufferPoolBackend --- second-stage initialization of a new backend
*
* This is called after we have acquired a PGPROC and so can safely get
* LWLocks. We don't currently need to do anything at this stage ...
* except register a shmem-exit callback. AtProcExit_Buffers needs LWLock
* access, and thereby has to be called at the corresponding phase of
* backend shutdown.
*/
void
InitBufferPoolBackend(void)
{
/*
* AtProcExit_Buffers needs LWLock access, and thereby has to be called at
* the corresponding phase of backend shutdown.
*/
Assert(MyProc != NULL);
on_shmem_exit(AtProcExit_Buffers, 0);
}