At 03:51 AM 9/8/2011, Merlin Moncure wrote:
yeah -- but you only need to block selects if you are selecting in the
inserting transaction (this is not a full upsert). if both writers
are doing:
begin;
lock table foo exclusive;
insert into foo select ... where ...;
commit;
is good enough. btw
At 03:51 AM 9/8/2011, Merlin Moncure wrote:
Don't you have to block SELECTs so that the SELECTs get serialized?
Otherwise concurrent SELECTs can occur at the same time, find no existing
rows, then all the inserts proceed and you get errors (or dupes).
That's how Postgresql still works
On Thu, Sep 8, 2011 at 9:14 AM, Lincoln Yeoh ly...@pop.jaring.my wrote:
At 03:51 AM 9/8/2011, Merlin Moncure wrote:
Don't you have to block SELECTs so that the SELECTs get serialized?
Otherwise concurrent SELECTs can occur at the same time, find no
existing
rows, then all the inserts
At 04:04 AM 9/8/2011, Andrew Sullivan wrote:
On Wed, Sep 07, 2011 at 02:51:32PM -0500, Merlin Moncure wrote:
@andrew s: going SERIALIZABLE doesn't help if you trying to eliminate
cases that would push you into retrying the transaction.
Well, no, of course. But why not catch the failure and
On Thu, Sep 08, 2011 at 10:31:39PM +0800, Lincoln Yeoh wrote:
Doesn't catching the failure and retrying mean writing more code?
Well, yes. OTOH, if you want to use upsert and you have to use
other database systems too, then you'll need that other code also,
since it's not standard.
There
At 05:23 AM 9/7/2011, Merlin Moncure wrote:
On Tue, Sep 6, 2011 at 3:45 PM, Merlin Moncure mmonc...@gmail.com wrote:
b) doesn't block reads if you lock in EXCLUSIVE mode. a) is the best
way to go if you prefer to handle errors on the client and/or
concurrency is important...c) otherwise.
On Wed, Sep 07, 2011 at 11:45:11PM +0800, Lincoln Yeoh wrote:
Don't you have to block SELECTs so that the SELECTs get serialized?
If you want to do that, why wouldn't you just use serializable mode?
A
--
Andrew Sullivan
a...@crankycanuck.ca
--
Sent via pgsql-general mailing list
On Wed, Sep 7, 2011 at 10:45 AM, Lincoln Yeoh ly...@pop.jaring.my wrote:
At 05:23 AM 9/7/2011, Merlin Moncure wrote:
On Tue, Sep 6, 2011 at 3:45 PM, Merlin Moncure mmonc...@gmail.com wrote:
b) doesn't block reads if you lock in EXCLUSIVE mode. a) is the best
way to go if you prefer to
On Wed, Sep 07, 2011 at 02:51:32PM -0500, Merlin Moncure wrote:
@andrew s: going SERIALIZABLE doesn't help if you trying to eliminate
cases that would push you into retrying the transaction.
Well, no, of course. But why not catch the failure and retry? I
guess I just don't get the problem,
On Wed, Sep 7, 2011 at 3:04 PM, Andrew Sullivan a...@crankycanuck.ca wrote:
On Wed, Sep 07, 2011 at 02:51:32PM -0500, Merlin Moncure wrote:
@andrew s: going SERIALIZABLE doesn't help if you trying to eliminate
cases that would push you into retrying the transaction.
Well, no, of course. But
At 07:02 PM 9/5/2011, J. Hondius wrote:
I agree that there are better ways to do this.
But for me this works. (legacy driven situation)
INSERT INTO tbinitialisatie (col1, col2)
SELECT 'x', 'y'
FROM tbinitialisatie
WHERE not exists (select * from tbinitialisatie where col1 = 'x'
and col2 =
On Tue, Sep 6, 2011 at 1:50 PM, Lincoln Yeoh ly...@pop.jaring.my wrote:
At 07:02 PM 9/5/2011, J. Hondius wrote:
I agree that there are better ways to do this.
But for me this works. (legacy driven situation)
INSERT INTO tbinitialisatie (col1, col2)
SELECT 'x', 'y'
FROM tbinitialisatie
On Tue, Sep 6, 2011 at 3:45 PM, Merlin Moncure mmonc...@gmail.com wrote:
On Tue, Sep 6, 2011 at 1:50 PM, Lincoln Yeoh ly...@pop.jaring.my wrote:
At 07:02 PM 9/5/2011, J. Hondius wrote:
I agree that there are better ways to do this.
But for me this works. (legacy driven situation)
INSERT
Hi follk
i trying to performe a conditional insert into a table, indeed, what i'm
trying to do is not insert a record into the table if that record exist
googleling i found something like
insert into XX values (1,2,3) where not exist (select );
but i'm having and error near where...
Στις Monday 05 September 2011 12:38:34 ο/η Pau Marc Muñoz Torres έγραψε:
Hi follk
i trying to performe a conditional insert into a table, indeed, what i'm
trying to do is not insert a record into the table if that record exist
thats why primary/unique keys are for.
isolate the columns
On 05/09/2011 10:38, Pau Marc Muñoz Torres wrote:
Hi follk
i trying to performe a conditional insert into a table, indeed, what
i'm trying to do is not insert a record into the table if that record exist
googleling i found something like
insert into XX values (1,2,3) where not exist
Pau Marc Muñoz Torres, 05.09.2011 11:38:
Hi follk
i trying to performe a conditional insert into a table, indeed, what i'm
trying to do is not insert a record into the table if that record exist
googleling i found something like
insert into XX values (1,2,3) where not exist (select
On 09/05/2011 12:38 PM, Pau Marc Muoz Torres wrote:
Hi follk
i trying to performe a conditional insert into a table, indeed,
what i'm trying to do is not insert a record into the table if
that record exist
googleling i found something like
i don't see it clear, let me put an example
i got the following table
molec varchar(30)
seq varchar(100)
where I insert my values
lets image that i have a record introduced as ('ubq', 'aadgylpittrs')
how i can prevent to insert another record where molec='ubq' ?
thanks
2011/9/5 Thomas
On 09/05/2011 01:37 PM, Pau Marc Muoz Torres wrote:
i don't see it clear, let me put an example
i got the following table
molec varchar(30)
seq varchar(100)
where I insert my values
lets image that i have a record introduced
Ok , thanks Sim, now i see it
P
2011/9/5 Sim Zacks s...@compulab.co.il
**
On 09/05/2011 01:37 PM, Pau Marc Muñoz Torres wrote:
i don't see it clear, let me put an example
i got the following table
molec varchar(30)
seq varchar(100)
where I insert my values
lets image that i have
I agree that there are better ways to do this.
But for me this works. (legacy driven situation)
INSERT INTO tbinitialisatie (col1, col2)
SELECT 'x', 'y'
FROM tbinitialisatie
WHERE not exists (select * from tbinitialisatie where col1 = 'x' and
col2 = 'y')
LIMIT 1
Pau Marc Muoz Torres
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