| From: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
|---|---|
| To: | Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk> |
| Cc: | blake(at)rcmail(dot)com, pgsql-bugs(at)postgresql(dot)org, Andres Freund <andres(at)anazarel(dot)de> |
| Subject: | Re: BUG #14231: logical replication wal sender process spins when using error traps in function |
| Date: | 2016-07-06 21:26:00 |
| Message-ID: | 20160706212600.GA649263@alvherre.pgsql |
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| Lists: | pgsql-bugs |
Andrew Gierth wrote:
> A quick scan of the code suggests that the worst case is when blocks are
> being freed in FIFO order, which seems quite plausible in this case, and
> the performance is potentially O(N^2).
>
> So I think this is primarily an artifact of doing so much retail
> palloc/pfree in a single memory context.
As I recall, this is the main reason Andres stuck the slab cache in
reorderbuffer. Maybe it'd be worthwhile to implement a different
MemoryContext tailored to this use case, and remove the slab cache
stuff.
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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