Re: Proposal: Global Index - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Proposal: Global Index
Date
Msg-id 20210111192555.GJ4320@momjian.us
Whole thread Raw
In response to Re: Proposal: Global Index  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: Proposal: Global Index  (Peter Geoghegan <pg@bowt.ie>)
List pgsql-hackers
On Mon, Jan 11, 2021 at 11:01:20AM -0800, Peter Geoghegan wrote:
> However, it probably would be okay if a global index feature performed
> poorly in scenarios where partitions get lots of UPDATEs that produce
> lots of index bloat and cause lots of LP_DEAD line pointers to
> accumulate in heap pages. It is probably reasonable to just expect
> users to not do that if they want to get acceptable performance while
> using a global index. Especially since it probably is not so bad if
> the index bloat situation gets out of hand for just one of the
> partitions (say the most recent one) every once in a while. You at
> least don't have the same crazy I/O multiplier effect that you
> described.

Once you layer on all the places a global index will be worse than just
creating a single large table, or a partitioned table with an index per
child, there might not be much usefulness left.  A POC patch might tell
us that, and might allow us to mark it as "not wanted".

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

  The usefulness of a cup is in its emptiness, Bruce Lee




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