Subject: Re: 001_rep_changes.pl stalls
To: Noah Misch <noah@leadboat.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Tom Lane
 <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org
References: <20200406063649.GA3738151@rfd.leadboat.com>
 <20200414013849.GA886648@rfd.leadboat.com> <8807.1586828716@sss.pgh.pa.us>
 <20200417054146.GA1061007@rfd.leadboat.com>
 <fba5fc85-205a-3aeb-9bf6-a124f762aa27@oss.nttdata.com>
 <20200418070142.GA1075445@rfd.leadboat.com>
 <dcdb33ba-4bcc-d41e-4aad-23207e195ccf@oss.nttdata.com>
 <20200420070215.GA1395671@rfd.leadboat.com>
From: Fujii Masao <masao.fujii@oss.nttdata.com>
Message-ID: <7492aa54-dabf-3791-cbc4-e653760a2288@oss.nttdata.com>
Date: Mon, 20 Apr 2020 19:24:28 +0900
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On 2020/04/20 16:02, Noah Misch wrote:
> On Mon, Apr 20, 2020 at 02:30:08PM +0900, Fujii Masao wrote:
>> +		 * Block if we have unsent data.  XXX For logical replication, let
>> +		 * WalSndWaitForWal(), handle any other blocking; idle receivers need
>> +		 * its additional actions.  For physical replication, also block if
>> +		 * caught up; its send_data does not block.
>>
>> It might be better to s/WalSndWaitForWal()/send_data()? Because not only
>> WalSndWaitForWal() but also WalSndWriteData() seems to handle the blocking.
>> WalSndWriteData() is called also under send_data, i.e., XLogSendLogical().
> 
> Thanks for reviewing.  WalSndWriteData() blocks when we have unsent data,
> which is the same cause for blocking in WalSndLoop().  Since the comment you
> quote says we let WalSndWaitForWal() "handle any other blocking", I don't
> think your proposed change makes it more correct.

I was misreading this as something like "any other blocking than
the blocking in WalSndLoop()". Ok, I have no more comments on
the patch.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION