On 07/28/2016 03:16 PM, Bruce Momjian wrote: > On Thu, Jul 28, 2016 at 12:35:23AM -0700, Jeff Janes wrote: >> On Wed, Jul 27, 2016 at 9:48 PM, John R Pierce <pierce@xxxxxxxxxxxx> wrote: >>> On 7/27/2016 9:39 PM, Jeff Janes wrote: >>>> >>>> That depends on how how many objects there are consuming that 1 TB. >>>> With millions of small objects, you will have problems. Not as many >>>> in 9.5 as there were in 9.1, but still it does not scale linearly in >>>> the number of objects. If you only have thousands of objects, then as >>>> far as I know -k works like a charm. >>> >>> >>> millions of tables? >> >> Well, it was a problem at much smaller values, until we fixed many of >> them. But the perversity is, if you are stuck on a version before the >> fixes, the problems prevent you from getting to a version on which it >> is not a problem any more. > > Uh, that is only true if the slowness was in _dumping_ many objects. > Most of the fixes have been for _restoring_ many objects, and that is > done in the new cluster, so they should be OK. Not really true. I ran into two separate cases where on older (pre 9.3 I believe) Postgres if you had hundreds of thousands of tables (in the case I remember well, it was about 500k tables) the schema dump from the old cluster basically never finished (ok, was killed after about a week). I had to find the patch that fixed a good bit of the slowness and backport it to the older version so we could successfully run pg_upgrade (in something like 14 hours instead of 7+ days). Joe -- Crunchy Data - http://crunchydata.com PostgreSQL Support for Secure Enterprises Consulting, Training, & Open Source Development
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