Re: Question about loading up a table

On Tue, Aug 1, 2017 at 4:27 PM, Alex Samad <alex(at)samad(dot)com(dot)au> wrote:
> Hi
>
> So just to go over what i have
>
>
> server A (this is the original pgsql server 9.2)
>
> Server X and Server Y ... PGSQL 9.6 in a cluster - streaming replication
> with hot standby.
>
>
> I have 2 tables about 2.5T of diskspace.
>
> I want to get the date from A into X and X will replicate into Y.
>
>
> I am currently on X using this command
>
> pg_dump -U <USER> -h <Server A > -t BIGTABLE -a <DB> | sudo -u postgres -i
> psql -q <DB>;
>
> This is taking a long time, its been 2 days and I have xfered around 2T..
> This is just a test to see how long and to populate my new UAT env. so I
> will have to do it again.
>
> Problem is time. the pg_dump process is single threaded.
> I have 2 routers in between A and X but its 10G networking - but my network
> graphs don't show much traffic.
>
> Server X is still in use, there are still records being inserted into the
> tables.
>
> How can I make this faster.
>
> I could shutdown server A and present the disks to server X, could I load
> this up in PGSQL and do a table to table copy - i presume this would be
> faster ... is this possible ? how do I get around the same DB name ?
> What other solutions do I have ?

Yes, but if it's taking days to transfer 2TB then you need to
investigate where your performance is tanking.

Have you tried resyncing / scping files across the network to see how
fast your network connection is?

Have you tried just pg_dumping / restoring locally to get an idea how
fast you can dump / restore withoout doing it over a network
connection?

Are you IO bound? Network bound? CPU bound?

Is the destination copying data, or building indexes? Do you insert
into a schema that already has indexes in place? If so have you tried
dropping the indexes first and rebuilding them?