Re: ANALYZE being a read v write operation clarification - Mailing list pgsql-docs

From David G. Johnston
Subject Re: ANALYZE being a read v write operation clarification
Date
Msg-id CAKFQuwZwbuSoQGaTDRSg6e9YysaJWi29a5imSeUQA76n9ehTKQ@mail.gmail.com
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In response to ANALYZE being a read v write operation clarification  (PG Doc comments form <noreply@postgresql.org>)
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On Friday, September 12, 2025, PG Doc comments form <noreply@postgresql.org> wrote:
The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/17/sql-analyze.html
Description:

In the ANALYZE docs it states,
- "ANALYZE collects statistics about the contents of tables in the database,
and stores the results in the pg_statistic system catalog"
- "ANALYZE requires only a read lock on the target table".

When trying to determien if this command could be run with
`default_transaction_read_only` set to `on,` I was left stumped on whether
this is a read only or read-write operation. It is unclear to me, what
"stores" in the context of the "pg_statistic system catalog" means, and
whether that requires a write operation. I'm potentially missing
understanding on the workings of the `pg_statistic` system catalog, but
figured this could be a small improvement made to clarify the docs about
this operation.

Yes, it is a write operation - otherwise it would be pretty useless since it has no output to the client.

It reads the contents of the named table, computes statistics, and then saves/stores/writes them for future reference - the location being saved to is a system catalog (a special kind of table).

If you want to propose a complete suggestion here it would be entertained, but none of the terms seem problematic on their own. Though maybe some requiring looking up if one is unfamiliar.  “stores the results in the system catalog” vs. “writes the results to the system catalog” seems like a pure style choice.  They mean the same thing.  Though I’m probably biased as a native English speaker.  But I’d want some other opinions in favor of changing it before I’d try to go improve it.

David J.

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