Re: Wal keep segment

Hi Don,

I am using wal_keep_segments for streaming replication and not replication
slots.
max_replication_slots is provided as 10 inside postgresql.conf, but no
replication slots are actually used, as you can see them from the below
queries.

*wal_keep_segments = 256 # in logfile segments; 0 disables*
*max_replication_slots = 10 # max number of replication slots*

edb=# select * from pg_replication_slots ;
slot_name | plugin | slot_type | datoid | database | temporary | active |
active_pid | xmin | catalog_xmin | restart_l
sn | confirmed_flush_lsn
-----------+--------+-----------+--------+----------+-----------+--------+------------+------+--------------+----------
---+---------------------
(0 rows)

edb=#

edb=# select * from pg_stat_replication ;
-[ RECORD 1 ]----+---------------------------------
pid | 19445
backend_xmin |
state | streaming
sent_lsn | 1B3/A6000000
write_lsn | 1B3/A6000000
flush_lsn | 1B3/A6000000
replay_lsn | 1B3/A6000000
write_lag |
flush_lag |
replay_lag |
sync_priority | 0
sync_state | async

Thanks and Regards,
Raj Kumar

On Sat, Apr 25, 2020 at 6:59 PM Don Seiler <don(at)seiler(dot)us> wrote:

> On Sat, Apr 25, 2020, 08:13 Raj kumar <rajkumar820999(at)gmail(dot)com> wrote:
>
>> Hi John,
>>
>> Thank you.
>>
>> On Sat, 25 Apr 2020, 17:45 John Scalia, <jayknowsunix(at)gmail(dot)com> wrote:
>>
>>> Wal_keep_segments is a MINIMUM setting value, meaning the database is
>>> guaranteed to keep at least that many WAL segments. If you have replication
>>> setup and it’s fallen behind or broken, then WAL segments can rapidly
>>> accumulate on a fairly busy server. I suspect without having your details
>>> that something of this nature is occurring.
>>> —
>>> Jay
>>>
>>> Sent from my iPad
>>>
>>> > On Apr 25, 2020, at 8:09 AM, Raj kumar <rajkumar820999(at)gmail(dot)com>
>>> wrote:
>>> >
>>> > 
>>> > Hi,
>>> >
>>> > I have "wal_keep_segment" set as 256.
>>> > But I could see that around 700 files are present inside pg_wal
>>> directory.
>>> >
>>> > I thought after reaching 256, wal writer will start overwriting from
>>> 1st.
>>> >
>>> > What is the upper limit of these number of wal files in the directory?
>>> >
>>> > Thanks and regards
>>> > Raj kumar
>>>
>>
> I would also see if you have a replication slot in use, and verify that it
> actually should be in use.
>
> Don.
>
>>