Re: PG as in-memory db? How to warm up and re-populate buffers? How to read in all tuples into memory?

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От Stefan Keller
Тема Re: PG as in-memory db? How to warm up and re-populate buffers? How to read in all tuples into memory?
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Msg-id CAFcOn28yyQgkw9iKfBcehFzR9s0_998TwzPhrhsuupMTtWHnmA@mail.gmail.com
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Ответ на Re: PG as in-memory db? How to warm up and re-populate buffers? How to read in all tuples into memory?  (Stefan Keller <sfkeller@gmail.com>)
Ответы Re: PG as in-memory db? How to warm up and re-populate buffers? How to read in all tuples into memory?  (Jeff Janes <jeff.janes@gmail.com>)
Список pgsql-performance
2012/2/29 Stefan Keller <sfkeller@gmail.com>:
> 2012/2/29 Jeff Janes <jeff.janes@gmail.com>:
>>> It's quite possible the vacuum full is thrashing your disk cache due
>>> to maintainance_work_mem. You can overcome this issue with the tar
>>> trick, which is more easily performed as:
>>>
>>> tar cf /dev/null $PG_DATA/base
>>
>> But on many implementations, that will not work.  tar detects the
>> output is going to the bit bucket, and so doesn't bother to actually
>> read the data.
>
> Right.
> But what about the commands cp $PG_DATA/base /dev/null or cat
> $PG_DATA/base > /dev/null ?
> They seem to do something.

...or let's try /dev/zero instead /dev/null:
tar cf /dev/zero $PG_DATA/base

-Stefan

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