Horton

Re: Improving connection scalability: GetSnapshotData()

Andrew Dunstan <andrew.dunstan@2ndquadrant.com>

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From: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
To: Andres Freund <andres@anarazel.de>
Cc: Ian Barwick <ian.barwick@2ndquadrant.com>, Michael Paquier <michael@paquier.xyz>, Tom Lane <tgl@sss.pgh.pa.us>, Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Daniel Gustafsson <daniel@yesql.se>, "Jonathan S. Katz" <jkatz@postgresql.org>, Alexander Korotkov <a.korotkov@postgrespro.ru>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Peter Geoghegan <pg@bowt.ie>, Bruce Momjian <bruce@momjian.us>, David Rowley <dgrowleyml@gmail.com>
Date: 2020-10-01T23:21:14Z
Lists: pgsql-hackers 
On 10/1/20 4:22 PM, Andres Freund wrote:
> Hi,
>
> On 2020-10-01 16:00:20 -0400, Andrew Dunstan wrote:
>> My strong suspicion is that we're getting unwanted CRs. Note the
>> presence of numerous instances of this in PostgresNode.pm:
>
>>     $stdout =~ s/\r\n/\n/g if $Config{osname} eq 'msys';
>>
>> So you probably want something along those lines at the top of the loop
>> in send_query_and_wait:
>>
>>     $$psql{stdout} =~ s/\r\n/\n/g if $Config{osname} eq 'msys';
> Yikes, that's ugly :(.
>
>
> I assume it's not, as the comments says
> 	# Note: on Windows, IPC::Run seems to convert \r\n to \n in program output
> 	# if we're using native Perl, but not if we're using MSys Perl.  So do it
> 	# by hand in the latter case, here and elsewhere.
> that IPC::Run converts things, but that native windows perl uses
> https://perldoc.perl.org/perlrun#PERLIO
> a PERLIO that includes :crlf, whereas msys probably doesn't?
>
> Any chance you could run something like
> perl -mPerlIO -e 'print(PerlIO::get_layers(STDIN), "\n");'
> on both native and msys perl?
>
>
>> possibly also for stderr, just to make it more futureproof, and at the
>> top of the file:
>>
>>     use Config;
>>
>>
>> Do you want me to test that first?
> That'd be awesome.
>
>
>

The change I suggested makes jacana happy.


cheers


andrew


-- 
Andrew Dunstan                https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Try to unbreak 021_row_visibility.pl on mingw.

  2. Fix and test snapshot behavior on standby.

  3. Fix race condition in snapshot caching when 2PC is used.

  4. snapshot scalability: cache snapshots using a xact completion counter.

  5. Fix use of wrong index in ComputeXidHorizons().

  6. Make vacuum a bit more verbose to debug BF failure.

  7. snapshot scalability: Introduce dense array of in-progress xids.

  8. snapshot scalability: Move PGXACT->vacuumFlags to ProcGlobal->vacuumFlags.

  9. snapshot scalability: Move subxact info to ProcGlobal, remove PGXACT.

  10. snapshot scalability: Move PGXACT->xmin back to PGPROC.

  11. snapshot scalability: Don't compute global horizons while building snapshots.

  12. BRIN: Handle concurrent desummarization properly

  13. Track latest completed xid as a FullTransactionId.

  14. Rename VariableCacheData.nextFullXid to nextXid.

  15. snapshot scalability: Move delayChkpt from PGXACT to PGPROC.

  16. Report progress of CREATE INDEX operations