Thread: A couple of pg_dump questions

A couple of pg_dump questions

From
Ron
Date:
$ pg_dump --host=farawaysrvr -Fc $REMOTEDB > /local/disk/backups/$REMOTEDB.dump

Is the data compressed on the remote server (thus minimizing traffic on the 
wire), or locally?  (I'd test this myself, but the company has really strict 
firewall rules in place.)

$ pg_dump --host=farawaysrvr -Fc -j4 $REMOTEDB > 
/local/disk/backups/$REMOTEDB.dump

Will parallel backups work if pg_dump is v9.6 and the remote system is v8.4?

Thanks

-- 
Angular momentum makes the world go 'round.


Re: A couple of pg_dump questions

From
"David G. Johnston"
Date:
On Thu, Apr 19, 2018 at 3:39 PM, Ron <ronljohnsonjr@gmail.com> wrote:

$ pg_dump --host=farawaysrvr -Fc $REMOTEDB > /local/disk/backups/$REMOTEDB.dump

Is the data compressed on the remote server (thus minimizing traffic on the wire), or locally?  (I'd test this myself, but the company has really strict firewall rules in place.)

The ​pg_dump client doesn't get any special treatment in terms of the amount of data being sent over the wire from the server.  It issues "COPY TO STDOUT" commands on the server and captures the results and, while packaging them up, performs any requested compression.​  To what extent the server compresses all its sent content I am unsure though it does some.

$ pg_dump --host=farawaysrvr -Fc -j4 $REMOTEDB > /local/disk/backups/$REMOTEDB.dump

Will parallel backups work if pg_dump is v9.6 and the remote system is v8.4?

​The last paragraph of the 9.6 pg_dump --jobs documentation covers pre-9.2 server dumps.

David J.

Re: A couple of pg_dump questions

From
Vick Khera
Date:
On Thu, Apr 19, 2018 at 6:39 PM, Ron <ronljohnsonjr@gmail.com> wrote:

$ pg_dump --host=farawaysrvr -Fc $REMOTEDB > /local/disk/backups/$REMOTEDB.dump

Is the data compressed on the remote server (thus minimizing traffic on the wire), or locally?  (I'd test this myself, but the company has really strict firewall rules in place.)


The compression is done locally. If your network is slower than compression, then you could tunnel it through an SSH connection with compression enabled.

As for your parallel dump, you cannot do that to stdout and "c" format. You have to tell pg_dump the directory name to write, as that is the only format that supports parallel dumps.