| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Can a background worker exist without shared memory access for EXEC_BACKEND cases? |
| Date: | 2020-08-04 16:50:29 |
| Message-ID: | CA+TgmoaxRVjcXq+-Bx24WPJQPBSgHO_sedMEP-ie-C9K4mnGtA@mail.gmail.com |
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On Tue, Aug 4, 2020 at 7:27 AM Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
> I could get these points earlier in my initial analysis. In fact, I
> could figure out the flow on Windows, how these parameters are shared
> using a shared file(CreateFileMapping(), MapViewOfFile()), and the
> shared file name being passed as an argv[2] to the child process, and
> the way child process uses this file name to read the backend
> parameters in read_backend_variables().
Doesn't that happen even if the background worker isn't declared to
use BGWORKER_SHMEM_ACCESS? See StartBackgroundWorker(): IIUC, we start
with shared memory access, then afterwards detach.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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