Re: Inefficiency in parallel pg_restore with many tables
Alvaro Herrera <alvherre@alvh.no-ip.org>
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andrew Dunstan <andrew@dunslane.net>, pgsql-hackers@lists.postgresql.org
Date: 2023-09-03T10:04:00Z
Lists: pgsql-hackers
On 2023-Sep-02, Nathan Bossart wrote: > On Fri, Sep 01, 2023 at 01:52:48PM -0700, Nathan Bossart wrote: > > Yeah, something similar to simplehash for binary heaps could be nice. That > > being said, I don't know if there's a strong reason to specialize the > > implementation for a given C data type in most cases. > > I ended up hacking together a (nowhere near committable) patch to see how > hard it would be to allow using any type with binaryheap. It doesn't seem > too bad. Yeah, using void * seems to lead to interfaces that are pretty much the same as bsearch() or qsort(). (Why isn't your payload type const, though?) I do wonder why did you change _remove_first and _first to have a 'result' output argument instead of a return value. Does this change actually buy you anything? simplehash.h doesn't do that either. > -extern void binaryheap_add(binaryheap *heap, Datum d); > -extern Datum binaryheap_first(binaryheap *heap); > -extern Datum binaryheap_remove_first(binaryheap *heap); > -extern void binaryheap_replace_first(binaryheap *heap, Datum d); > +extern void binaryheap_add(binaryheap *heap, void *d); > +extern void binaryheap_first(binaryheap *heap, void *result); > +extern void binaryheap_remove_first(binaryheap *heap, void *result); > +extern void binaryheap_replace_first(binaryheap *heap, void *d); -- Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
Commits
-
Remove open-coded binary heap in pg_dump_sort.c.
- 559bc1732180 17.0 landed
-
Convert pg_restore's ready_list to a priority queue.
- 9bfd44bbde42 17.0 landed
-
Add function for removing arbitrary nodes in binaryheap.
- c103d073819a 17.0 landed
-
Make binaryheap available to frontend code.
- 5af0263afd7b 17.0 landed