Re: PostgresSQL 9.5.21 very slow to connect and perform basic queries

Thanks for the quick response.

OS/version: CentOS release 6.9 (Final)

Hardware(non dedicated to the db, other services and app run the same
server):

Xeon(R) CPU E5-2690 v4 @ 2.60GHz - 56 cores - 504 GB RAM

logicaldrive 1 (1.5 TB, RAID 1, OK)
physicaldrive 1I:3:1 (port 1I:box 3:bay 1, Solid State SAS, 1600.3 GB, OK)
physicaldrive 1I:3:2 (port 1I:box 3:bay 2, Solid State SAS, 1600.3 GB, OK)

GUC Settings:
auto_explain.log_analyze 0
auto_explain.log_min_duration 1000
auto_explain.log_nested_statements 0
auto_explain.log_verbose 0
autovacuum_analyze_scale_factor 0.1
autovacuum_analyze_threshold 50
autovacuum_freeze_max_age 200000000
autovacuum_max_workers 3
autovacuum_multixact_freeze_max_age 400000000
autovacuum_naptime 60
autovacuum_vacuum_cost_delay 2
autovacuum_vacuum_cost_limit 100
autovacuum_vacuum_scale_factor 0.1
autovacuum_vacuum_threshold 50
autovacuum_work_mem -1
checkpoint_timeout 2700
effective_cache_size 4194304
enable_seqscan 0
log_autovacuum_min_duration 250
log_checkpoints 1
log_connections 1
log_file_mode 600
log_lock_waits 1
log_min_duration_statement 1000
log_rotation_age 1440
log_truncate_on_rotation 1
maintenance_work_mem 262144
max_connections 300
max_replication_slots 10
max_wal_senders 10
max_wal_size 1280
max_worker_processes 15
min_wal_size 5
pg_stat_statements.max 10000
standard_conforming_strings 1
track_commit_timestamp 1
wal_receiver_timeout 0
wal_sender_timeout 0
work_mem 8192

On Thu, Jul 21, 2022 at 3:33 PM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:

> On Thu, Jul 21, 2022 at 02:37:35PM -0400, bruno da silva wrote:
> > I'm investigating an issue on a PostgresSql 9.5.21 installation that
> > becomes unusable in an intermittent way. Simple queries like "select
> > now();" could take 20s. commits take 2s. and all gets fixed after an
> engine
> > restart.
> >
> > I look into the pg logs and no signs of errors. and checkpoints are
> > always timed. The machine is well provisioned, load isn't too high, and
> cpu
> > io wait is under 1%.
> >
> > any suggestions on what I should check more?
>
> What OS/version is it ?
>
> What GUCs have you changed ?
>
> Is it a new issue ?
>
> https://wiki.postgresql.org/wiki/Slow_Query_Questions
>
> Operating system+version
> What OS / version ? At least for linux, you can get the distribution by
> running: tail /etc/*release
>
> GUC Settings
> What database configuration settings have you changed? What are their
> values? (These are things like "shared_buffers", "work_mem",
> "enable_seq_scan", "effective_io_concurrency", "effective_cache_size",
> etc). See Server Configuration for a useful query that will show all of
> your non-default database settings, in an easier to read format than
> posting pieces of your postgresql.conf file.
>
> --
> Justin
>

--
Bruno da Silva