wal_dump output on CREATE DATABASE

[Jean-Christophe Arnu]

Dear hackers,

This is my first try to post on that list to propose a workaround on an
issue I noticed while using pg_waldump. Each  time an object is referenced
by "oids" following  output template :
tablespace oid/database oid/relfilenodeid

That template seems to be used for each operation but the *copy dir*
operation. The latter is performed (at least) when CREATE DATABASE
statement is called with the template: oid/tablespace oid

Exemple on CREATE DATABASE (without defining a template database) :
rmgr: Database    len (rec/tot):     42/    42, tx:        568, lsn:
0/01865790, prev 0/01865720, desc: CREATE copy dir 1/1663 to 16384/1663


It comes out (to me) it may be more consistent to use the same template
than the other operations in pg_waldump.
I propose to swap the parameters positions for the copy dir operation
output.

You'll find a patch file included which does the switching job :
rmgr: Database    len (rec/tot):     42/    42, tx:        568, lsn:
0/01865790, prev 0/01865720, desc: CREATE copy dir 1663/1 to 1663/16384



   - Project name ; PostgreSQL
   - File : copy_dir_message_switch_parameters_v0.patch
   - Description : Swaps copy dir output parameters
   - This patch is not WIP (but may be discussed)
   - Patch applied against master branch
   - Compiles and tests successfully
   - No platform specific code
   - No need of regression test
   - Not a new feature
   - No performance impact

Any comment or advice are more than welcome.

If I didn't do the things the right way, I would appreciate some help from
a kind mentor.

I'll put the patch for the next commitfest.

Thank you,
-- 
Jean-Christophe Arnu

diff --git a/src/backend/access/rmgrdesc/dbasedesc.c b/src/backend/access/rmgrdesc/dbasedesc.c
index 39e26d7ed4..7ee120f1d9 100644
--- a/src/backend/access/rmgrdesc/dbasedesc.c
+++ b/src/backend/access/rmgrdesc/dbasedesc.c
@@ -29,15 +29,15 @@ dbase_desc(StringInfo buf, XLogReaderState *record)
 		xl_dbase_create_rec *xlrec = (xl_dbase_create_rec *) rec;
 
 		appendStringInfo(buf, "copy dir %u/%u to %u/%u",
-						 xlrec->src_db_id, xlrec->src_tablespace_id,
-						 xlrec->db_id, xlrec->tablespace_id);
+						 xlrec->src_tablespace_id, xlrec->src_db_id,
+						 xlrec->tablespace_id, xlrec->db_id);
 	}
 	else if (info == XLOG_DBASE_DROP)
 	{
 		xl_dbase_drop_rec *xlrec = (xl_dbase_drop_rec *) rec;
 
 		appendStringInfo(buf, "dir %u/%u",
-						 xlrec->db_id, xlrec->tablespace_id);
+						 xlrec->tablespace_id, xlrec->db_id);
 	}
 }