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Replace the pg_listener-based LISTEN/NOTIFY mechanism with an in-memory queue.

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In addition, add support for a "payload" string to be passed along with
each notify event.

This implementation should be significantly more efficient than the old one,
and is also more compatible with Hot Standby usage.  There is not yet any
facility for HS slaves to receive notifications generated on the master,
although such a thing is possible in future.

Joachim Wieland, reviewed by Jeff Davis; also hacked on by me.
This commit is contained in:
Tom Lane
2010-02-16 22:34:57 +00:00
parent fc5173ad51
commit d1e027221d
37 changed files with 1831 additions and 744 deletions
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27
src/include/access/slru.h
View File

@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/slru.h,v 1.25 2010/01/02 16:58:00 momjian Exp $
* $PostgreSQL: pgsql/src/include/access/slru.h,v 1.26 2010/02/16 22:34:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -17,6 +17,25 @@
#include "storage/lwlock.h"
/*
* Define SLRU segment size. A page is the same BLCKSZ as is used everywhere
* else in Postgres. The segment size can be chosen somewhat arbitrarily;
* we make it 32 pages by default, or 256Kb, i.e. 1M transactions for CLOG
* or 64K transactions for SUBTRANS.
*
* Note: because TransactionIds are 32 bits and wrap around at 0xFFFFFFFF,
* page numbering also wraps around at 0xFFFFFFFF/xxxx_XACTS_PER_PAGE (where
* xxxx is CLOG or SUBTRANS, respectively), and segment numbering at
* 0xFFFFFFFF/xxxx_XACTS_PER_PAGE/SLRU_PAGES_PER_SEGMENT. We need
* take no explicit notice of that fact in slru.c, except when comparing
* segment and page numbers in SimpleLruTruncate (see PagePrecedes()).
*
* Note: slru.c currently assumes that segment file names will be four hex
* digits. This sets a lower bound on the segment size (64K transactions
* for 32-bit TransactionIds).
*/
#define SLRU_PAGES_PER_SEGMENT 32
/*
* Page status codes. Note that these do not include the "dirty" bit.
* page_dirty can be TRUE only in the VALID or WRITE_IN_PROGRESS states;
@@ -55,8 +74,8 @@ typedef struct SlruSharedData
/*
* Optional array of WAL flush LSNs associated with entries in the SLRU
* pages. If not zero/NULL, we must flush WAL before writing pages (true
* for pg_clog, false for multixact and pg_subtrans). group_lsn[] has
* lsn_groups_per_page entries per buffer slot, each containing the
* for pg_clog, false for multixact, pg_subtrans, pg_notify). group_lsn[]
* has lsn_groups_per_page entries per buffer slot, each containing the
* highest LSN known for a contiguous group of SLRU entries on that slot's
* page.
*/
@@ -94,7 +113,7 @@ typedef struct SlruCtlData
/*
* This flag tells whether to fsync writes (true for pg_clog and multixact
* stuff, false for pg_subtrans).
* stuff, false for pg_subtrans and pg_notify).
*/
bool do_fsync;

7
src/include/access/twophase_rmgr.h
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/twophase_rmgr.h,v 1.11 2010/01/02 16:58:00 momjian Exp $
* $PostgreSQL: pgsql/src/include/access/twophase_rmgr.h,v 1.12 2010/02/16 22:34:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -23,9 +23,8 @@ typedef uint8 TwoPhaseRmgrId;
*/
#define TWOPHASE_RM_END_ID 0
#define TWOPHASE_RM_LOCK_ID 1
#define TWOPHASE_RM_NOTIFY_ID 2
#define TWOPHASE_RM_PGSTAT_ID 3
#define TWOPHASE_RM_MULTIXACT_ID 4
#define TWOPHASE_RM_PGSTAT_ID 2
#define TWOPHASE_RM_MULTIXACT_ID 3
#define TWOPHASE_RM_MAX_ID TWOPHASE_RM_MULTIXACT_ID
extern const TwoPhaseCallback twophase_recover_callbacks[];