rdelaage/postgresql
1
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-07-21 14:19:39 +02:00
Code Issues Packages Projects Releases Wiki Activity

Fix double shared memory allocation.

Browse Source 
SLRU buffer lwlocks are allocated twice by oversight in commit
fe702a7b3f where that locks were moved to
separate tranche. The bug doesn't have user-visible effects except small
overspending of shared memory.

Backpatch to 9.6 where it was introduced.

Alexander Korotkov with small editorization by me.
This commit is contained in:
Teodor Sigaev 2017-07-21 13:31:49 +03:00
parent 5512427b19
commit 38a4a5349c
1 changed files with 7 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
src/backend/access/transam/slru.c
View File

@ -204,15 +204,16 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
shared->page_lru_count = (int *) (ptr + offset);
offset += MAXALIGN(nslots * sizeof(int));
/* Initialize LWLocks */
shared->buffer_locks = (LWLockPadded *) (ptr + offset);
offset += MAXALIGN(nslots * sizeof(LWLockPadded));
if (nlsns > 0)
{
shared->group_lsn = (XLogRecPtr *) (ptr + offset);
offset += MAXALIGN(nslots * nlsns * sizeof(XLogRecPtr));
}
/* Initialize LWLocks */
shared->buffer_locks = (LWLockPadded *) ShmemAlloc(sizeof(LWLockPadded) * nslots);
Assert(strlen(name) + 1 < SLRU_MAX_NAME_LENGTH);
strlcpy(shared->lwlock_tranche_name, name, SLRU_MAX_NAME_LENGTH);
shared->lwlock_tranche_id = tranche_id;
@ -232,6 +233,9 @@ SimpleLruInit(SlruCtl ctl, const char *name, int nslots, int nlsns,
shared->page_lru_count[slotno] = 0;
ptr += BLCKSZ;
}
/* Should fit to estimated shmem size */
Assert(ptr - (char *) shared <= SimpleLruShmemSize(nslots, nlsns));
}
else
Assert(found);