From: steve@outtalimits.com.au
To: Thomas Jacob <jacob@internet24.de>
Cc: pgsql-admin@postgresql.org
Subject: Re: DB Dump Size
Date: Fri, 15 Aug 2008 11:09:02 +1000
Message-ID: <e7a17e8b398d35d87c0b50ce9eae7b4d@127.0.0.1> (raw)
In-Reply-To: <20080815001525.GA26208@internet24.de>
References: <326684d8c021f4afb82f8e921f9e0c40@127.0.0.1>
<20080814083003.GA456@internet24.de>
<02f4fac97d67bb4a1cee604724c8d62d@127.0.0.1>
<20080815001525.GA26208@internet24.de>
Nice, that has cleared it up.
I am on 8.1 also.
On my test box, a standard dump took 6m 26sec & a -Fc dump took 11min 2sec.
That's not a great difference, but the size difference is quite noticeable.
Thanks for your help.
Steve.
On Fri, 15 Aug 2008 02:15:25 +0200, Thomas Jacob <jacob@internet24.de>
wrote:
> On Fri, Aug 15, 2008 at 09:26:18AM +1000, steve@outtalimits.com.au wrote:
>> G'day,
>>
>> I am just running a straight pg_dump with no options.
>> With the -Fc option the DB size is reduced to about: 700MB
>>
>> Is the -Fc a compressed format? Are there any limitations or side
> effects
>> to using this output, is it slower?? etc etc. Can this output be
> restored
>> via the normal method of: psql dbname < sql.dump
>
> Yes -Fc is a compressed format. From the man page of pg_dump:
>
> "custom: Output a custom archive suitable for input into pg_restore.
> This is the most flexible format in that it allows reordering of loading
> data as well as object definitions. This format is also compressed by
> default."
>
> Whether or not the dump takes less or more time probably depends
> on your spare CPU vs your spare IO capacity, in general I'd
> say it isn't slower, given today's CPU, but I haven't measured
> this.
>
> For restoring the DB you need to run the dump through pg_restore first,
> which gives you various dials to control what to restore
> and how, and then feed it into psql as usual. This gives you
> more flexibility than with the plain SQL dump. Also, you
> can recreate a plain SQL dump with pg_restore should
> you require one.
>
> One drawback could be that if you lose your DB and something
> also damages parts of your dumps, a compressed format might mean you
can't
> restore any data at all, vs. at least some data
> with plain SQL dump. But that's not a very likely
> scenario, is it? ;-)
>
> Also, you can't always restore from an -Fc dump, if
> your pg_restore version is much older than the one that
> particular dump was created with. For instance, trying
> to restore an 8.3.3 dump with a 7.4.19 pg_restore I
> get:
>
> "pg_restore: [archiver] unsupported version (1.10) in file header"
>
> When I use a 8.1.11 pg_restore, it seems to work fine.
> But that's hardly a suprising result.
>
> Thomas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: steve@outtalimits.com.au, jacob@internet24.de
Subject: Re: DB Dump Size
In-Reply-To: <e7a17e8b398d35d87c0b50ce9eae7b4d@127.0.0.1>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox