| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Peter Geoghegan <pg(at)bowt(dot)ie> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, 曾文旌 <wenjing(dot)zwj(at)alibaba-inc(dot)com>, Julien Rouhaud <rjuju123(at)gmail(dot)com>, Ibrar Ahmed <ibrar(dot)ahmad(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Amit Langote <amitlangote09(at)gmail(dot)com>, Hamid Akhtar <hamid(dot)akhtar(at)gmail(dot)com>, "heikki(dot)linnakangas" <heikki(dot)linnakangas(at)iki(dot)fi>, "Nasby, Jim" <nasbyj(at)amazon(dot)com>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> |
| Subject: | Re: Proposal: Global Index |
| Date: | 2021-01-11 19:25:55 |
| Message-ID: | 20210111192555.GJ4320@momjian.us |
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| Lists: | 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(at)momjian(dot)us> https://momjian.us
EnterpriseDB https://enterprisedb.com
The usefulness of a cup is in its emptiness, Bruce Lee
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