Horton

Re: PROC_IN_ANALYZE stillborn 13 years ago

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@2ndquadrant.com>, James Coleman <jtc331@gmail.com>, pgsql-hackers <pgsql-hackers@lists.postgresql.org>, Simon Riggs <simon@2ndquadrant.com>
Date: 2020-08-06T18:48:52Z
Lists: pgsql-hackers 
On Thu, Aug 6, 2020 at 2:37 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> +1 for removal.  It's not clear to me that we'd ever put it back.
> Long-running ANALYZE snapshots are indeed a problem, but Simon's proposal
> upthread to just take a new one every so often seems like a much cleaner
> and simpler answer than having onlookers assume that it's safe to ignore
> ANALYZE processes.  (Given that ANALYZE can invoke user-defined functions,
> and can be invoked from inside user transactions, any such assumption
> seems horribly dangerous.

Not to get too far from the proposal on the table of just removing
something that's been unused for a really long time, which stands on
its own merits, but if a particular ANALYZE doesn't invoke any
user-defined functions and isn't run inside a transaction, could we
skip acquiring a snapshot altogether? That's an extremely common case,
though by no means universal.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Call out vacuum considerations in create index docs

  2. Document concurrent indexes waiting on each other

  3. snapshot scalability: Don't compute global horizons while building snapshots.

  4. Remove PROC_IN_ANALYZE and derived flags

  5. Improve performance of get_actual_variable_range with recently-dead tuples.