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From: Tom Lane <tgl@sss.pgh.pa.us>
To: =?UTF-8?B?0JLQsNGB0LjQu9GM0LXQsiDQlNC80LjRgtGA0LjQuQ==?=
 <d.vasilyev@postgrespro.ru>
cc: Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org
Subject: Re: Performance degradation in commit ac1d794
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Comments: In-reply-to =?UTF-8?B?0JLQsNGB0LjQu9GM0LXQsiDQlNC80LjRgtGA0LjQuQ==?=
 <d.vasilyev@postgrespro.ru>
 message dated "Fri, 25 Dec 2015 20:53:13 +0300"
Date: Fri, 25 Dec 2015 13:10:23 -0500
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=?UTF-8?B?0JLQsNGB0LjQu9GM0LXQsiDQlNC80LjRgtGA0LjQuQ==?= <d.vasilyev@postgrespro.ru> writes:
> ​ Samples: 1M of event 'cycles', Event count (approx.): 816922259995, UID:
> pgpro
>   Overhead  Shared Object       Symbol

>   69,72%  [kernel]            [k] _raw_spin_lock_irqsave
>   1,43%  postgres            [.] _bt_compare
>    1,19%  postgres            [.] LWLockAcquire
>    0,99%  postgres            [.] hash_search_with_hash_value
>    0,61%  postgres            [.] PinBuffer

Seems like what you've got here is a kernel bug.

			regards, tom lane


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