Mysterious locking problem

I'm having a misterious locking problem ( caused by a transaction, i think ).
But for my understanding of transactions and lock's, this wasnt supposed
to appen.
I'm using Postgresq 7.1.2 on a Suse 7.x box.

I notice the locking problem when there are two 2 different queries
running, of different connections( initiated by PHP ).
Lets say I have 3 Tables:

- Table A, B, C

The query that is executed by one of the connections is a select on table
B( to get some foreign keys values ) and an insert in table A( just after
the select ).
The other query that the second connection execute is an insert into
table C( to start this insert it does some selects in table B ).

Given your query things above I'm guessing you've turned on query
printing? Are the selects perhaps SELECT ... FOR UPDATE queries going for
the same rows in which case I think the second would wait on the first?

Hi,

thank's for reppling.

Given your query things above I'm guessing you've turned on query
printing?

Query print is off, because that will startve may hardisk verry quickly.

Are the selects perhaps SELECT ... FOR UPDATE queries going

I forgot to mention that the selects are plain selects( not select for
update ).

for the same rows in which case I think the second would wait on the
first?

Can this be a PHP issue?
I have noticed the "locking", because the script line that executes the
query, doesnt ever return( until i stock the first query ).
Regards,
Miguel Carvalho

On Tue, 21 May 2002, Miguel Carvalho wrote:

Hi,

thank's for reppling.

Given your query things above I'm guessing you've turned on query
printing?

Query print is off, because that will startve may hardisk verry quickly.

Are the selects perhaps SELECT ... FOR UPDATE queries going

I forgot to mention that the selects are plain selects( not select for
update ).

You might want to turn query printing on for just short time to see if
there are other queries being done. Do you have any foreign keys or
triggers on these tables that might be doing so?

for the same rows in which case I think the second would wait on the
first?

Can this be a PHP issue?

Seems wierd for it to be.

Can you distill what you're doing into a small reproducable example and
send enough information to reproduce it?

On Tue, 21 May 2002, Miguel Carvalho wrote:

Hi,

thank's for reppling.

Given your query things above I'm guessing you've turned on query
printing?

Query print is off, because that will startve may hardisk verry
quickly.

Are the selects perhaps SELECT ... FOR UPDATE queries going

I forgot to mention that the selects are plain selects( not select
for update ).

You might want to turn query printing on for just short time to see if
there are other queries being done.

Ok, i will try it.

Do you have any foreign keys or
triggers on these tables that might be doing so?

On one of the tables i have a trigger before insert, but the trigger isnt
doing any row or table locking. The tirgger is just executing some
validations( plain selects ). Can this be the problem?

for the same rows in which case I think the second would wait on the
first?

I agree with you.

Can this be a PHP issue?

Seems wierd for it to be.

Ok, i am going to dig into the problem.

Can you distill what you're doing into a small reproducable example and
send enough information to reproduce it?

I'am gone try.

Regards,
Miguel Carvalho