RE: Slow queries after Windows startup - Mailing list pgsql-performance

No, I have not checked it.
How can I monitor it on Windows? Do you know a tool that can help me?

Thanks!

-----Message d'origine-----
De : Robert Zenz [mailto:robert.zenz@sibvisions.com]
Envoyé : jeudi 11 janvier 2018 10:01
À : pgsql-performance@lists.postgresql.org
Objet : Re: Slow queries after Windows startup

Have you verified that this is isn't caused by cold filesystem caches?


On 11.01.2018 09:19, POUSSEL, Guillaume wrote:
> Hello,
>
>
>
> I’m running PostgreSQL 9.3 on Windows 7 and I’m having a performance
> issue at startup. I have installed PostgreSQL as a service through
> Windows installer.
>
> The database size is 3 Go, with 120 tables.
>
>
>
> Every time I try to run queries right after Windows startup, it takes
> a huge amount of time.
>
> If I restart the PostgreSQL Windows service, queries are way faster.
>
>
>
> I have activated debug log and here is what I get before Windows restart:
>
> duration: 2.000 ms  parse
>
> duration: 3.000 ms  bind
>
> duration: 0.000 ms  execute
>
> And after Windows restart:
>
> duration: 364.000 ms  parse
>
> duration: 415.000 ms  bind
>
> duration: 0.000 ms  execute
>
>
> For information, the test query is:
>
> SELECT t.typlen FROM pg_catalog.pg_type t, pg_catalog.pg_namespace n
> WHERE t.typnamespace=n.oid AND t.typname='name' AND n.nspname='pg_catalog'
>
> It’s not related to the query itself since other queries give the same
> result (from 10x to 100x longer).
>
>
>
> Here are my settings (all log and locale-related settings omitted on
> purpose):
>
>
> bytea_output
>
> escape
>
> session
>
>
> checkpoint_segments
>
> 45
>
> configuration file
>
>
> client_encoding
>
> UNICODE
>
> session
>
>
> client_min_messages
>
> notice
>
> session
>
>
> DateStyle
>
> ISO, DMY
>
> session
>
>
> debug_pretty_print
>
> on
>
> configuration file
>
>
> debug_print_plan
>
> on
>
> configuration file
>
>
> default_text_search_config
>
> pg_catalog.french
>
> configuration file
>
>
> listen_addresses
>
> *
>
> configuration file
>
>
> logging_collector
>
> on
>
> configuration file
>
>
> max_connections
>
> 100
>
> configuration file
>
>
> max_stack_depth
>
> 2MB
>
> environment variable
>
>
> port
>
> 5432
>
> configuration file
>
>
> shared_buffers
>
> 128MB
>
> configuration file
>
>
> TimeZone
>
> GMT
>
> user
>
>
>
> I run queries through JDBC driver (9.3-1100-jdbc4.jar). I know that
> the issue is not related to the PC, since it give the same result on a
> bunch of different computers.
>
>
>
> I have two questions:
>
> *         What is the difference between restarting PostgreSQL service and
> restarting the computer? Is PostgreSQL relying on some kind of
> OS-level cache outside Windows service?
>
> *         How can I dig down deeper and see what’s causing PostgreSQL
> slowdown?
>
>
>
> Thanks in advance for your help,
>
> BR,
>
>
>
> Guillaume POUSSEL | ♠Sogeti High Tech
>
>  <mailto:guillaume.poussel@sogeti.com> guillaume.poussel@sogeti.com
>
>
>
>
>
>
>
>
>
>
>
>
>
>
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