| From: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
|---|---|
| To: | Antonin Houska <ah(at)cybertec(dot)at> |
| Cc: | Michael Paquier <michael(at)paquier(dot)xyz>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Attempt to consolidate reading of XLOG page |
| Date: | 2019-11-22 22:56:32 |
| Message-ID: | 20191122225632.GA9169@alvherre.pgsql |
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| Lists: | pgsql-hackers |
On 2019-Nov-22, Antonin Houska wrote:
> As I pointed out in
>
> https://www.postgresql.org/message-id/88183.1574261429%40antos
>
> seg.ws_off only replaced readOff in XLogReaderState. So we should only update
> ws_off where readOff was updated before commit 709d003. This does happen in
> ReadPageInternal (see HEAD) and I see no reason for the final patch to update
> ws_off anywhere else.
Oh you're right.
I see no reason to leave ws_off. We can move that to XLogReaderState; I
did that here. We also need the offset in WALReadError, though, so I
added it there too. Conceptually it seems clearer to me this way.
What do you think of the attached?
BTW I'm not clear what errors can pread()/pg_pread() report that do not
set errno. I think lines 1083/1084 of WALRead are spurious now.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
| Attachment | Content-Type | Size |
|---|---|---|
| v12-0001-Use-only-xlogreader.c-WALRead.patch | text/x-diff | 33.1 KB |
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