Re: Avoid erroring out when unable to remove or parse logical rewrite files to save checkpoint work

Nathan Bossart <nathandbossart@gmail.com>

From: Nathan Bossart <nathandbossart@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Michael Paquier <michael@paquier.xyz>, Thomas Munro <thomas.munro@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, "Bossart, Nathan" <bossartn@amazon.com>, Julien Rouhaud <rjuju123@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-08-31T19:24:28Z
Lists: pgsql-hackers
On Wed, Aug 31, 2022 at 12:14:33PM -0700, Andres Freund wrote:
> On 2022-08-27 14:06:32 +0530, Bharath Rupireddy wrote:
>> -		if (lstat(fromfile, &fst) < 0)
>> -			ereport(ERROR,
>> -					(errcode_for_file_access(),
>> -					 errmsg("could not stat file \"%s\": %m", fromfile)));
>> +		xlde_type = get_dirent_type(fromfile, xlde, false, ERROR);
>>  
>> -		if (S_ISDIR(fst.st_mode))
>> +		if (xlde_type == PGFILETYPE_DIR)
>>  		{
>>  			/* recurse to handle subdirectories */
>>  			if (recurse)
>>  				copydir(fromfile, tofile, true);
>>  		}
>> -		else if (S_ISREG(fst.st_mode))
>> +		else if (xlde_type == PGFILETYPE_REG)
>>  			copy_file(fromfile, tofile);
>>  	}
>>  	FreeDir(xldir);
> 
> It continues to make no sense to me to add behaviour changes around
> error-handling as part of a conversion to get_dirent_type(). I don't at all
> understand why e.g. the above change to make copydir() silently skip over
> files it can't stat is ok?

In this example, the call to get_dirent_type() should ERROR if the call to
lstat() fails (the "elevel" argument is set to ERROR).
-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com



Commits

  1. Expand the use of get_dirent_type(), shaving a few calls to stat()/lstat()

  2. fsync pg_logical/mappings in CheckPointLogicalRewriteHeap().

  3. Introduce logical decoding.