Обсуждение: pgsql: Provide much better wait information in pg_stat_activity.
Provide much better wait information in pg_stat_activity. When a process is waiting for a heavyweight lock, we will now indicate the type of heavyweight lock for which it is waiting. Also, you can now see when a process is waiting for a lightweight lock - in which case we will indicate the individual lock name or the tranche, as appropriate - or for a buffer pin. Amit Kapila, Ildus Kurbangaliev, reviewed by me. Lots of helpful discussion and suggestions by many others, including Alexander Korotkov, Vladimir Borodin, and many others. Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/53be0b1add7064ca5db3cd884302dfc3268d884e Modified Files -------------- doc/src/sgml/monitoring.sgml | 414 +++++++++++++++++++++++++++++++++- src/backend/access/transam/xact.c | 13 +- src/backend/bootstrap/bootstrap.c | 2 + src/backend/catalog/system_views.sql | 3 +- src/backend/postmaster/bgwriter.c | 3 + src/backend/postmaster/checkpointer.c | 1 + src/backend/postmaster/pgstat.c | 116 +++++++--- src/backend/postmaster/walwriter.c | 2 + src/backend/replication/walsender.c | 2 + src/backend/storage/buffer/bufmgr.c | 5 + src/backend/storage/lmgr/lmgr.c | 23 ++ src/backend/storage/lmgr/lock.c | 6 +- src/backend/storage/lmgr/lwlock.c | 67 +++++- src/backend/storage/lmgr/proc.c | 3 + src/backend/utils/adt/lockfuncs.c | 2 +- src/backend/utils/adt/pgstatfuncs.c | 126 +++++++---- src/include/catalog/catversion.h | 2 +- src/include/catalog/pg_proc.h | 8 +- src/include/pgstat.h | 81 ++++++- src/include/storage/lmgr.h | 2 + src/include/storage/lock.h | 2 + src/include/storage/lwlock.h | 2 + src/include/storage/proc.h | 2 + src/test/regress/expected/rules.out | 9 +- 24 files changed, 794 insertions(+), 102 deletions(-)
Hi
2016-03-10 19:55 GMT+01:00 Robert Haas <rhaas@postgresql.org>:
Provide much better wait information in pg_stat_activity.
When a process is waiting for a heavyweight lock, we will now indicate
the type of heavyweight lock for which it is waiting. Also, you can
now see when a process is waiting for a lightweight lock - in which
case we will indicate the individual lock name or the tranche, as
appropriate - or for a buffer pin.
Amit Kapila, Ildus Kurbangaliev, reviewed by me. Lots of helpful
discussion and suggestions by many others, including Alexander
Korotkov, Vladimir Borodin, and many others.
Branch
------
master
I am trying to test this feature, and there I see not actual data. Maybe this behave is not related to this patch:
create table foo(a int);
insert into foo values(10);
session one:
begin; select * from foo for update;
session two:
begin; select * from foo for update;
session two is waiting
session one:
select * from pg_stat_activity -- I don't see correct information about session two
session two:
rollback; begin; select * from foo where a = 10 for update;
session two is waiting again
session one:
select * from pg_stat_activity; -- The content is not changed
So content of pg_stat_activity is not correct in holder lock session. Independent third session see valid content of pg_stat_activity.
Hypothesis: the pg_stat_activity is not refreshed under opened transaction?
Regards
Pavel
On 2016-03-10 18:55:47 +0000, Robert Haas wrote:
> Provide much better wait information in pg_stat_activity.
>
> When a process is waiting for a heavyweight lock, we will now indicate
> the type of heavyweight lock for which it is waiting. Also, you can
> now see when a process is waiting for a lightweight lock - in which
> case we will indicate the individual lock name or the tranche, as
> appropriate - or for a buffer pin.
My compiler quite validly complains:
/home/andres/src/postgresql/src/backend/storage/lmgr/lmgr.c: In function ‘GetLockNameFromTagType’:
/home/andres/src/postgresql/src/backend/storage/lmgr/lmgr.c:1018:9: warning: function may return address of local
variable[-Wreturn-local-addr]
return locktypename;
^
/home/andres/src/postgresql/src/backend/storage/lmgr/lmgr.c:1007:8: note: declared here
char tnbuf[32];
^
In file included from /home/andres/src/postgresql/src/backend/commands/dbcommands.c:20:0:
Andres
On 3/10/16 7:32 PM, Andres Freund wrote: > On 2016-03-10 18:55:47 +0000, Robert Haas wrote: >> Provide much better wait information in pg_stat_activity. >> >> When a process is waiting for a heavyweight lock, we will now indicate >> the type of heavyweight lock for which it is waiting. Also, you can >> now see when a process is waiting for a lightweight lock - in which >> case we will indicate the individual lock name or the tranche, as >> appropriate - or for a buffer pin. > > My compiler quite validly complains: > > /home/andres/src/postgresql/src/backend/storage/lmgr/lmgr.c: In function ‘GetLockNameFromTagType’: > /home/andres/src/postgresql/src/backend/storage/lmgr/lmgr.c:1018:9: warning: function may return address of local variable[-Wreturn-local-addr] > return locktypename; > ^ > /home/andres/src/postgresql/src/backend/storage/lmgr/lmgr.c:1007:8: note: declared here > char tnbuf[32]; > ^ > In file included from /home/andres/src/postgresql/src/backend/commands/dbcommands.c:20:0: Needs a "static", it seems.