[Pgpool-hackers] First try at rephrasing the documentation

[Tatsuo Ishii]

> I will try to answer your TODO items one by one following emals...

TODO : what does this refer to, there is no 3 in the array ?
A: It referes to "row mode".

TODO : is that true ? It seems to me the JDBC driver starts a
transaction only on first DDL query (in read committed mode at least).

A: Really? I do not observe what you said with
postgresql-8.4-701.jdbc4.jar.

TODO: Are DDL queries accounted for in the load balancing algorithm ?
A: Yes.

TODO: can a table be non-distributed and non-replicated, and still be
used in parallel mode ?
A: Not sure. will check.

TODO: should we define 'pool' in this context ? I find it a bit confusing
A: The reason why we use 'pool' is just for a historical reason...

TODO: Should be explained in more detail. I guess it's only for the
'rsync' method, not PITR…
A: You are correct.

TODO: What is the point of 'flushing the sequences' ? Don't we trust
WAL recovery ?
A: PostgreSQL does not log sequence value whenever it counts
up. Instead it logs 'discretely'. So just redoing from WAL, it's
possible that slave loses upto 32 sequences. See
src/backend/commands/sequence.c.

TODO: contradiction in the previous sentence md5 is supported by using
"pool_passwd".
A: You are correct.

TODO: what happens then ? Is it rejected ?
A: No. Inconsistent values will be inserted.

TODO: I don't really get this one. Can somebody explain ?
A: Me neither:-) Let me check...

<p>The USING CLAUSE is converted to an ON CLAUSE by the query rewrite process.
Therefore, when "*" is used at target list, the row of the same column name appears.</p>
TODO: What does it mean ?
A: I don't know neither:-) Let me check...

TODO: This following section may be completely false. I tried to
understand the general meaning of the original text, and look into
pgpool's code to understand.
A: Let me check...
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp