database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-23 14:01:44 +03:00
Code Activity

Change the way that LWLocks for extensions are allocated.

Browse Source 
The previous RequestAddinLWLocks() method had several disadvantages.
First, the locks would be in the main tranche; we've recently decided
that it's useful for LWLocks used for separate purposes to have
separate tranche IDs.  Second, there wasn't any correlation between
what code called RequestAddinLWLocks() and what code called
LWLockAssign(); when multiple modules are in use, it could become
quite difficult to troubleshoot problems where LWLockAssign() ran out
of locks.  To fix, create a concept of named LWLock tranches which
can be used either by extension or by core code.

Amit Kapila and Robert Haas
This commit is contained in:
Robert Haas
2016-02-04 16:43:04 -05:00
parent 5ef244a282
commit c1772ad922
7 changed files with 210 additions and 50 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
contrib/pg_stat_statements/pg_stat_statements.c
View File

@ -404,7 +404,7 @@ _PG_init(void)
* resources in pgss_shmem_startup().
*/
RequestAddinShmemSpace(pgss_memsize());
RequestAddinLWLocks(1);
RequestNamedLWLockTranche("pg_stat_statements", 1);
/*
* Install hooks.
@ -480,7 +480,7 @@ pgss_shmem_startup(void)
if (!found)
{
/* First time through ... */
pgss->lock = LWLockAssign();
pgss->lock = &(GetNamedLWLockTranche("pg_stat_statements"))->lock;
pgss->cur_median_usage = ASSUMED_MEDIAN_INIT;
pgss->mean_query_len = ASSUMED_LENGTH_INIT;
SpinLockInit(&pgss->mutex);