Thread

1. moving from 6.3.2 to 6.5

   Mario Jorge Nunes Filipe <mjnf@neptuno.sc.uevora.pt> — 1999-08-13T11:25:27Z

   Hi
   
   I have a relatively large application developed with php and postgres
   using pg 6.3.2. I read the changelog for v.6.5 and i got a little bit
   scared, but maybe i understood things in the wrong way.
   
   In this application every "race condition" is placed in a begin->end
   block and most of them even have lock's before they're needed just mo
   make sure. If I upgrade postgres to 6.5 is there any danger that with
   the new locking mechanism my app's database starts getting corrupted or
   start's giving out the wrong type of information?
   
   Thanks
   -- 
           Mario Filipe 
           mjnf@uevora.pt
           http://neptuno.sc.uevora.pt/~mjnf
   
   

2. Re: [GENERAL] moving from 6.3.2 to 6.5

   Mario Jorge Nunes Filipe <mjnf@neptuno.sc.uevora.pt> — 1999-08-13T11:39:56Z

   Mario Jorge Nunes Filipe wrote:
   > 
   > Hi
   > 
   > I have a relatively large application developed with php and postgres
   > using pg 6.3.2. I read the changelog for v.6.5 and i got a little bit
   > scared, but maybe i understood things in the wrong way.
   > 
   > In this application every "race condition" is placed in a begin->end
   > block and most of them even have lock's before they're needed just mo
   > make sure. If I upgrade postgres to 6.5 is there any danger that with
   > the new locking mechanism my app's database starts getting corrupted or
   > start's giving out the wrong type of information?
   	
   	Ok! Mea culpa. I probably didn't read the RELEASE file but i just saw a
   message from someone with a similar problem.
   
   	So, correct me if i'm wrong, as long as i use LOCK's i won't be running
   into trouble, right ?
   
   	BTW, do i have to install 6.4 to pass from 6.3 to 6.5?
   
   P.S : I'm not thinking about upgrading the production server yetm just
   the devel one...
   
   -- 
           Mario Filipe 
           mjnf@uevora.pt
           http://neptuno.sc.uevora.pt/~mjnf
   
   

3. Re: [GENERAL] moving from 6.3.2 to 6.5

   Vadim Mikheev <vadim@krs.ru> — 1999-08-17T01:48:51Z

   Mario Jorge Nunes Filipe wrote:
   > 
   > Hi
   > 
   > I have a relatively large application developed with php and postgres
   > using pg 6.3.2. I read the changelog for v.6.5 and i got a little bit
   > scared, but maybe i understood things in the wrong way.
   > 
   > In this application every "race condition" is placed in a begin->end
   > block and most of them even have lock's before they're needed just mo
   > make sure. If I upgrade postgres to 6.5 is there any danger that with
   > the new locking mechanism my app's database starts getting corrupted or
   > start's giving out the wrong type of information?
   
   In 6.5.X LOCK TABLE without any option (without IN ... MODE)
   does the same things as in prev versions: it stops _any_
   (both read and write) concurrent access to locked table.
   It's bad for performance of read-only transactions - 
   I would recommend to use LOCK TABLE IN EXCLUSIVE MODE
   to block write access (insert/update/delete/select_for_update)
   in update transactions and use SERIALIZABLE mode in read-only
   ones.
   
   Vadim