Re: Is there any way to request unique lwlock inside a backgroundworker in PG9.4? - Mailing list pgsql-hackers

From Hubert Zhang
Subject Re: Is there any way to request unique lwlock inside a backgroundworker in PG9.4?
Date
Msg-id CAB0yre=p_kDfPPj_tC2UCrwpWdSzesS9i6p+9xr5r0LUw0KV6Q@mail.gmail.com
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In response to Re: Is there any way to request unique lwlock inside a backgroundworker in PG9.4?  (Amit Kapila <amit.kapila16@gmail.com>)
Responses Re: Is there any way to request unique lwlock inside a backgroundworker in PG9.4?  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
Hi Amit

The section "Share Memory and LWLocks" describe the AddinShmemInitLock which is used to protect the ShmemInitStruct() when backend workers initialize their shm.  My requirement is to how to protect the shm access within the bgworkers(not at init stage). This lock should be bgworkers specific.

On Wed, Oct 17, 2018 at 7:51 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
On Wed, Oct 17, 2018 at 3:49 PM Hubert Zhang <hzhang@pivotal.io> wrote:
>
> Hi all,
>
> I want to init SHM in a background worker, which is supported in PG9.4. Also I need to use lwlock to protect the share memory inside the worker code.
>
> RequestNamedLWLockTranche is the way to handle it, but it's not supported in PG 9.4, is there any way I could request an unique lock inside worker init code in PG 9.4?
>

You might want to look at section "Shared Memory and LWLocks" in the docs [1].

[1] - https://www.postgresql.org/docs/9.4/static/xfunc-c.html

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com


--
Thanks

Hubert Zhang

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