Re: [PATCHES] Implemented current_query

Поиск
Список
Период
Сортировка
От Bruce Momjian
Тема Re: [PATCHES] Implemented current_query
Дата
Msg-id 200803281723.m2SHN9320702@momjian.us
обсуждение исходный текст
Ответы Re: [PATCHES] Implemented current_query  (Tomas Doran <bobtfish@bobtfish.net>)
Список pgsql-hackers
Neil Conway wrote:
> On Mon, 2007-07-05 at 19:48 +0100, Tomas Doran wrote:
> > As suggested in the TODO list (and as I need the functionality  
> > myself), I have implemented the current_query interface to  
> > debug_query_string.

It actually has been removed from the TODO list since you saw it last.

> Comments:
> 
...
> * AFAIK debug_query_string() still does the wrong thing when the user
> submits multiple queries in a single protocol message (separated by
> semi-colons). Not sure there's a way to fix that that is both easy and
> efficient, though...

The problem with the last bullet is pretty serious.  It can be
illustrated with psql:
$ psql -c 'set log_statement="all";select 1;select 2;' test

Server log shows:
STATEMENT:  set log_statement=all;select 1;select 2;

Obviously this is what current_query() would return if we commit this
patch, and it probably isn't 100% accurate.  I see dblink exposes this:
   http://www.postgresql.org/docs/8.3/static/contrib-dblink-current-query.html
   Returns the currently executing interactive command string of the   local database session, or NULL if it can't be
determined. Note   that this function is not really related to <filename>dblink</>'s   other functionality.  It is
providedsince it is sometimes useful   in generating queries to be forwarded to remote databases.
 

but making it more widely available with a possible inaccurate result is
a problem.  We can't think of anyway to fix this cleanly --- it would
require a separate parser pass to split queries by semicolons (which
psql does by default in interactive mode).  Right now the parser does
the splitting as part of its normal single-parse operation and just
creates parse trees that don't have string representations.

Perhaps we could name it received_query() to indicate it is what the
backend received and it not necessarily the _current_ query.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + If your life is a hard drive, Christ can be your backup. +


В списке pgsql-hackers по дате отправления:

Предыдущее
От: Zdenek Kotala
Дата:
Сообщение: Is psql command line interface broken on HEAD?
Следующее
От: Gregory Stark
Дата:
Сообщение: Re: Prereading using posix_fadvise