Horton

Re: [PATCH 04/16] Add embedded list interface (header only)

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@2ndquadrant.com>
Cc: Peter Geoghegan <peter@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@postgresql.org
Date: 2012-06-22T14:41:20Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Don't waste the last segment of each 4GB logical log file.

  2. Stamp HEAD as 9.3devel.

  3. Wake WALSender to reduce data loss at failover for async commit.

  4. Make the visibility map crash-safe.

Andres Freund <andres@2ndquadrant.com> writes:
> Oh, I and Peter weren't talking about the pg_list.h stuff, it was about my 
> 'embedded list' implementation which started this subthread. The 
> pg_list.h/list.c stuff isn't problematic as far as I have seen in profiles; 
> its checks are pretty simple so I do not find that surprising. We might want 
> to disable it by default anyway.

> In my code the list checking stuff iterates over the complete list after 
> modifications and checks that all prev/next pointers are correct so its linear 
> in itself...

Well, so does list.c, so I'd expect the performance risks to be similar.
Possibly you're testing on longer lists than are typical in the backend.

			regards, tom lane