PostgreSQL and cgroup - Mailing list pgsql-general
| From | 高健 |
|---|---|
| Subject | PostgreSQL and cgroup |
| Date | |
| Msg-id | CAL454F2GoUSZm3-dOBtYRQ+uUsQ39emfgK_0sQ3O-sX1j86NLQ@mail.gmail.com Whole thread Raw |
| Responses |
Re: PostgreSQL and cgroup
(高健 <luckyjackgao@gmail.com>)
|
| List | pgsql-general |
Hello:
Step3: To start postgresql and deal with data:
Sorry for disturbing,
In order to make my question clear,
I wrote this one as a seperate question.
If using cgroup, I can find wget work well.
But , for postgresql, when I deal huge amount of data, it still report out of memory error. In fact I hope postgresql can work under a limit amount of memory.
My test is as this:
Step 1:To make memory limit through cgroup:
[postgres@cent6 Desktop]$ cat /etc/cgconfig.conf
...
mount {
cpuset = /cgroup/cpuset;
cpu = /cgroup/cpu;
cpuacct = /cgroup/cpuacct;
memory = /cgroup/memory;
devices = /cgroup/devices;
freezer = /cgroup/freezer;
net_cls = /cgroup/net_cls;
blkio = /cgroup/blkio;
}
group test1 {
perm {
task{
uid=postgres;
gid=postgres;
}
admin{
uid=root;
gid=root;
}
} memory {
memory.limit_in_bytes=30M;
}
}
[postgres@cent6 Desktop]$
[postgres@cent6 Desktop]$ cat /etc/cgrules.conf
# /etc/cgrules.conf
...
#<user> <controllers> <destination>
postgres memory test1/
#
[postgres@cent6 Desktop]$
[postgres@cent6 Desktop]$ chkconfig --list cgconfig
cgconfig 0:off 1:off 2:on 3:on 4:on 5:on 6:off
[postgres@cent6 Desktop]$ chkconfig --list cgred
cgred 0:off 1:off 2:on 3:on 4:on 5:on 6:off
[postgres@cent6 Desktop]$
Step 2 :To see memory :
[postgres@cent6 Desktop]$ free -m
total used free shared buffers cached
Mem: 2006 384 1622 0 26 138
-/+ buffers/cache: 219 1787
Swap: 4031 87 3944
[postgres@cent6 Desktop]$
Step3: To start postgresql and deal with data:
postgres=# select count(*) from test01;
count
-------
0
(1 row)
postgres=# insert into test01 values(generate_series(1,614400),repeat( chr(int4(random()*26)+65),1024));
Then, In psql client, I got:
The connection to the server was lost. Attempting reset: Failed.
!>
In postgresql's log, I found:
[postgres@cent6 pgsql]$ LOG: database system was shut down at 2013-09-09 16:20:29 CST
LOG: database system is ready to accept connections
LOG: autovacuum launcher started
LOG: server process (PID 2697) was terminated by signal 9: Killed
DETAIL: Failed process was running: insert into test01 values(generate_series(1,614400),repeat( chr(int4(random()*26)+65),1024));
LOG: terminating any other active server processes
WARNING: terminating connection because of crash of another server process
DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
HINT: In a moment you should be able to reconnect to the database and repeat your command.
FATAL: the database system is in recovery mode
LOG: all server processes terminated; reinitializing
LOG: database system was interrupted; last known up at 2013-09-09 17:35:42 CST
LOG: database system was not properly shut down; automatic recovery in progress
LOG: redo starts at 1/9E807C90
LOG: unexpected pageaddr 1/946BE000 in log file 1, segment 159, offset 7069696
LOG: redo done at 1/9F6BDB50
LOG: database system is ready to accept connections
LOG: autovacuum launcher started
When I see dmesg, I can see:
[postgres@cent6 Desktop]$ dmesg | grep post
[ 2673] 500 2673 64453 200 0 0 0 postgres
[ 2675] 500 2675 64494 79 0 0 0 postgres
[ 2676] 500 2676 64453 75 0 0 0 postgres
[ 2677] 500 2677 64453 77 0 0 0 postgres
[ 2678] 500 2678 64667 80 0 0 0 postgres
[ 2679] 500 2679 28359 72 0 0 0 postgres
[ 2697] 500 2697 64764 100 0 0 0 postgres
[ 2673] 500 2673 64453 200 0 0 0 postgres
[ 2675] 500 2675 64494 79 0 0 0 postgres
[ 2676] 500 2676 64453 75 0 0 0 postgres
[ 2677] 500 2677 64453 77 0 0 0 postgres
[ 2678] 500 2678 64667 80 0 0 0 postgres
[ 2679] 500 2679 28359 72 0 0 0 postgres
[ 2697] 500 2697 64764 100 0 0 0 postgres
[ 2673] 500 2673 64453 208 0 0 0 postgres
[ 2675] 500 2675 64494 79 0 0 0 postgres
[ 2676] 500 2676 64453 98 0 0 0 postgres
[ 2677] 500 2677 64453 782 0 0 0 postgres
[ 2678] 500 2678 64667 133 0 0 0 postgres
[ 2679] 500 2679 28359 86 0 0 0 postgres
[ 2697] 500 2697 73075 3036 0 0 0 postgres
Memory cgroup out of memory: Kill process 2697 (postgres) score 1000 or sacrifice child
Killed process 2697, UID 500, (postgres) total-vm:292300kB, anon-rss:8432kB, file-rss:3712kB
[postgres@cent6 Desktop]$
Although I encountered the out of memory , but it is cgroup out of memory.
I think that cgroup really influenced postgresql.
But not by the means I hope: I hope PG can work under limit , not to be killed by OOM.
My above sql statement quickly failed. that is: PG 's main process is killed by OOM because it is going to use memory more than 30M,which is limited by cgroup.
But If I run wget, wget can work well under memory limit:
So My question is:
Wen under cgroup's memory limit , Why PG crashed but wget do not?
Best Regards
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