moving from 6.3.2 to 6.5

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

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