Re: pg_dump slower than pg_restore - Mailing list pgsql-general

From Bosco Rama
Subject Re: pg_dump slower than pg_restore
Date
Msg-id 53B5F1A7.3020104@boscorama.com
Whole thread Raw
In response to Re: pg_dump slower than pg_restore  (David Wall <d.wall@computer.org>)
Responses Re: pg_dump slower than pg_restore
List pgsql-general
On 07/03/14 16:51, David Wall wrote:
>
> On 7/3/2014 10:36 AM, Bosco Rama wrote:
>> If those large objects are 'files' that are already compressed (e.g.
>> most image files and pdf's) you are spending a lot of time trying to
>> compress the compressed data ... and failing.
>>
>> Try setting the compression factor to an intermediate value, or even
>> zero (i.e. no dump compression).  For example, to get the 'low hanging
>> fruit' compressed:
>>      $ pg_dump -Z1 -Fc ...
>>
>> IIRC, the default value of '-Z' is 6.
>>
>> As usual your choice will be a run-time vs file-size trade-off so try
>> several values for '-Z' and see what works best for you.
>
> That's interesting.  Since I gzip the resulting output, I'll give -Z0 a
> try.  I didn't realize that any compression was on by default.

If you use gzip you will be doing the same 'possibly unnecessary'
compression step.  Use a similar approach to the gzip command as you
would for the pg_dump command.  That is, use one if the -[0-9] options,
like this:
  $ pg_dump -Z0 -Fc ... | gzip -[0-9] ...

> Thanks for the tip...

NP.

HTH,
Bosco.


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