| From: | Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> |
|---|---|
| To: | Peter Geoghegan <pg(at)bowt(dot)ie> |
| Cc: | Rushabh Lathia <rushabh(dot)lathia(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Corey Huinker <corey(dot)huinker(at)gmail(dot)com> |
| Subject: | Re: [HACKERS] Parallel tuplesort (for parallel B-Tree index creation) |
| Date: | 2017-12-08 02:03:50 |
| Message-ID: | CAEepm=2GE3vFkgzDsHcubOjE7DQLSjWLy_R315bD0u3yKvUWeQ@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, Dec 8, 2017 at 2:23 PM, Thomas Munro
<thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> On Fri, Dec 8, 2017 at 1:57 PM, Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
>> 1. Thomas' barrier abstraction was added by commit 1145acc7. I think
>> that you should use a static barrier in tuplesort.c now, and rip out
>> the ConditionVariable fields in the Sharedsort struct.
>
> ... So I think we'd need to add an extra barrier
> function that lets you change the party size of a static barrier.
Something like the attached (untested), which would allow
_bt_begin_parallel() to call BarrierInit(&barrier, request + 1), then
BarrierForgetParticipants(&barrier, request -
pcxt->nworkers_launched), and then all the condition variable loop
stuff can be replaced with a well placed call to
BarrierArriveAndWait(&barrier, WAIT_EVENT_SOMETHING_SOMETHING).
--
Thomas Munro
http://www.enterprisedb.com
| Attachment | Content-Type | Size |
|---|---|---|
| barrier-forget-participants-v1.patch | application/octet-stream | 2.6 KB |
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