Thanks for pointing out those links. I am trying to figure out how they can help me.
One more thing, I can't understand the postgresql.log duration vs. a "EXPLAIN ANALYZE" in the query:
Postgresql.log gives:
duration: 628.000 ms parse (...)
duration: 0.000 ms bind (...)
duration: 378.000 ms execute (...)
EXPLAIN gives:
(...)
I/O Timings: read=0.019
(...)
Total runtime: 0.167 ms
Where are all these milliseconds (378ms vs. 0.167ms)?
What can be slowing down the query parsing?
-----Message d'origine-----
De : Robert Zenz [mailto:robert.zenz@sibvisions.com]
Envoyé : jeudi 11 janvier 2018 10:55
À : pgsql-performance@lists.postgresql.org
Objet : Re: Slow queries after Windows startup
I have no idea to be honest, I haven't done any Windows administration in a long time.
The best I could find is this:
* https://docs.microsoft.com/en-us/sysinternals/downloads/rammap
* https://technet.microsoft.com/en-us/library/cc938589.aspx
On 11.01.2018 10:06, POUSSEL, Guillaume wrote:
> 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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