Horton

Re: pgsql 10: hash indexes testing

AP <ap@zip.com.au>

View thread View on postgr.es
From: AP <ap@zip.com.au>
To: Jeff Janes <jeff.janes@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-07-05T09:31:40Z
Lists: pgsql-hackers 
On Tue, Jul 04, 2017 at 08:23:20PM -0700, Jeff Janes wrote:
> On Tue, Jul 4, 2017 at 3:57 AM, AP <ap@zip.com.au> wrote:
> > The data being indexed is BYTEA, (quasi)random and 64 bytes in size.
> > The table has over 2 billion entries. The data is not unique. There's
> > an average of 10 duplicates for every unique value.
> 
> What is the number of duplicates for the most common value?

Damn. Was going to collect this info as I was doing a fresh upload but
it fell through the cracks of my mind. It'll probably take at least
half a day to collect (a simple count(*) on the table takes 1.5-1.75
hours parallelised across 11 processes) so I'll probably have this in
around 24 hours if all goes well. (and I don't stuff up the SQL :) )

AP.

Commits

  1. pgstatindex: Insert some casts to prevent overflow.

  2. hash: Immediately after a bucket split, try to clean the old bucket.

  3. hash: Increase the number of possible overflow bitmaps by 8x.

  4. BRIN auto-summarization