To: "pgsql-admin@postgresql.org" <pgsql-admin@postgresql.org>
From: MichaelDBA <MichaelDBA@sqlexec.com>
Subject: "strange" pg_rewind error
Message-ID: <939b25f7-bc1b-ba32-fd3f-afed0f7c0702@sqlexec.com>
Date: Sun, 3 May 2020 08:57:13 -0400
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Here is my pg_rewind command.  Trying to make a former primary follow 
the newly-promoted standby...
/usr/pgsql-12/bin/pg_rewind -D '/apps/opt/postgres/pg12/data' 
--source-server='host=mypromotedstandby user=repmgr dbname=repmgr 
port=5432 password=mypassword connect_timeout=2'

Now I don't know if this matters but that log directory is actually a 
symlink pointing to a location that has log files in both the source and 
target.

Here is the error I get:
pg_rewind: servers diverged at WAL location 1/2F0000A0 on timeline 6
pg_rewind: rewinding from last common checkpoint at 1/2F000028 on timeline 6
pg_rewind: fatal: "/apps/opt/postgres/pg12/data/log" is not a directory

Here is the reference from the PostgreSQL source code where it is noted 
as "strange"
https://github.com/postgres/postgres/blob/master/src/bin/pg_rewind/filemap.c
process_source_file(const char *path, file_type_t type, size_t newsize,
                     const char *link_target)
{
...
...
...
     switch (type)
     {
         case FILE_TYPE_DIRECTORY:
             if (exists && !S_ISDIR(statbuf.st_mode) && strcmp(path, 
"pg_wal") != 0)
             {
                 /* it's a directory in source, but not in target. 
Strange.. */
                 pg_fatal("\"%s\" is not a directory", localpath);
             }

             if (!exists)
                 action = FILE_ACTION_CREATE;
             else
                 action = FILE_ACTION_NONE;
             oldsize = 0;
             break;

         case FILE_TYPE_SYMLINK:
             if (exists &&

Regards,
Michael Vitale


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Here is my pg_rewind command.  Trying to make a former primary follow 
the newly-promoted standby...<br>
/usr/pgsql-12/bin/pg_rewind -D '/apps/opt/postgres/pg12/data' 
--source-server='host=mypromotedstandby user=repmgr dbname=repmgr 
port=5432 password=mypassword connect_timeout=2'<br>
  <br>
Now I don't know if this matters but that log directory is actually a symlink
 pointing to a location that has log files in both the source and 
target.<br>
  <br>
Here is the error I get:<br>
pg_rewind: servers diverged at WAL location 1/2F0000A0 on timeline 6<br>
pg_rewind: rewinding from last common checkpoint at 1/2F000028 on 
timeline 6<br>
pg_rewind: fatal: "/apps/opt/postgres/pg12/data/log" is not a directory<br>
  <br>
Here is the reference from the PostgreSQL source code where it is noted 
as "strange"<br>
<a class="moz-txt-link-freetext" href="https://github.com/postgres/postgres/blob/master/src/bin/pg_rewind/filemap.c">https://github.com/postgres/postgres/blob/master/src/bin/pg_rewind/filemap.c</a><br>
process_source_file(const char *path, file_type_t type, size_t newsize,<br>
                    const char *link_target)<br>
{<br>
...<br>
...<br>
...<br>
    switch (type)<br>
    {<br>
        case FILE_TYPE_DIRECTORY:<br>
            if (exists &amp;&amp; !S_ISDIR(statbuf.st_mode) &amp;&amp; 
strcmp(path, "pg_wal") != 0)<br>
            {<br>
  <span style="font-weight: bold;">                /* it's a directory 
in source, but not in target. Strange.. */</span><br>
                pg_fatal("\"%s\" is not a directory", localpath);<br>
            }<br>
  <br>
            if (!exists)<br>
                action = FILE_ACTION_CREATE;<br>
            else<br>
                action = FILE_ACTION_NONE;<br>
            oldsize = 0;<br>
            break;<br>
  <br>
        case FILE_TYPE_SYMLINK:<br>
            if (exists &amp;&amp;<br>
  <br>
Regards,<br>
Michael Vitale<br>
  <br>
  <br>
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