Re: question

My question is for Francisco who replied regarding xz. I was curious what
options he used. Thanks.

On Fri, Oct 16, 2015 at 3:14 PM, Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 10/16/2015 12:10 PM, anj patnaik wrote:
>
>> Thanks. what is the recommended command/options for backup and how to
>> restore?
>>
>> I found the below online. let me know if this is better and how to
>> restore. Thank you
>>
>> pg_dump -Fc '<Db-Name>' | xz -3 dump.xz
>>
>
> Again, why would compress an already compressed output?
>
> Also online:
>
> http://www.postgresql.org/docs/9.4/interactive/app-pgdump.html
>
> http://www.postgresql.org/docs/9.4/interactive/app-pgrestore.html
>
> They step you through the backup and restore process.
>
>>
>>
>> On Fri, Oct 16, 2015 at 4:05 AM, Francisco Olarte
>> <folarte(at)peoplecall(dot)com <mailto:folarte(at)peoplecall(dot)com>> wrote:
>>
>> On Fri, Oct 16, 2015 at 8:27 AM, Guillaume Lelarge
>> <guillaume(at)lelarge(dot)info <mailto:guillaume(at)lelarge(dot)info>> wrote:
>> > 2015-10-15 23:05 GMT+02:00 Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com
>> <mailto:adrian(dot)klaver(at)aklaver(dot)com>>:
>> >> On 10/15/2015 01:35 PM, anj patnaik wrote:
>> ...
>> >>> ./pg_dump -t RECORDER -Fc postgres | gzip > /tmp/dump
>> >>> Are there any other options for large tables to run faster and
>> occupy
>> >>> less disk space?
>> >> Yes, do not double compress. -Fc already compresses the file.
>> > Right. But I'd say "use custom format but do not compress with
>> pg_dump". Use
>> > the -Z0 option to disable compression, and use an external
>> multi-threaded
>> > tool such as pigz or pbzip2 to get faster and better compression.
>>
>> Actually I would not recommend that, unless you are making a long term
>> or offsite copy. Doing it means you need to decompress the dump before
>> restoring or even testing it ( via i.e., pg_restore > /dev/null ).
>>
>> And if you are pressed on disk space you may corner yourself using
>> that on a situation where you do NOT have enough disk space for an
>> uncompressed dump. Given you normally are nervous enough when
>> restoring, for normal operations I think built in compression is
>> better.
>>
>> Also, I'm not current with the compressor Fc uses, I think it still is
>> gzip, which is not that bad and is normally quite fast ( In fact I do
>> not use that 'pbzip2', but I did some tests about a year ago and I
>> found bzip2 was beaten by xz quite easily ( That means on every level
>> of bzip2 one of the levels of xz beat it in BOTH size & time, that was
>> for my data, YMMV ).
>>
>>
>> Francisco Olarte.
>>
>>
>>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com
>