Re: [GENERAL] [JDBC] JDBC behaviour

[Craig Ringer]

On 18 February 2016 at 16:13, Vladimir Sitnikov  wrote:

If you want to shoot yourself in a foot for fun and profit, you can
> try https://github.com/pgjdbc/pgjdbc/pull/477.
>

I think this should be incorporated, once it's ready, as a non-default
connection option. It's handy for porting applications.

I think PostgreSQL's behaviour is the most correct, but if people are
porting apps and want to wear the performance impact of all those
savepoints and have written their code to handle partially-failed xacts,
then sure, they can have that.

I'm constantly astounded by how many people are willing to simply ignore
errors and carry on with the transaction without even properly verifying
that the error was the exact one they expected though. Seriously bad
application development and it *will* bite them. The best, most correct
thing to do remains to retry the whole transaction.

-- 
 Craig Ringer   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Re: [GENERAL] [JDBC] JDBC behaviour

[John R Pierce]

On 2/18/2016 12:26 AM, Sridhar N Bamandlapally wrote:

If we want transactions in "begin-end" then its fine,

but in this case all these transactions are independent with 
autocommit off,


with autocommit OFF, when you issue the first query, jdbc generates a 
postgresql BEGIN;  this starts a postgresql transaction. To end the 
transaction,  you have to explicitly .commit() or .rollback() 


with autocommit ON, then jdbc lets each query execute standalone, this 
is postgresql's default behavior if you don't use BEGIN...




--
john r pierce, recycling bits in santa cruz



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Re: [GENERAL] [JDBC] JDBC behaviour

[Sridhar N Bamandlapally]

Ok, let me put this way

in JDBC we have *setAutoCommit( false ) *, and all dmls are independent
transactions

and when any transaction fails then the session not allowing next
transactions

in Java when we do setAutoCommit( false ) its behaving like all
transactions in BEGIN-END block, this is not expected behavior

i guess this is bug





On Thu, Feb 18, 2016 at 2:00 PM, Vladimir Sitnikov <
sitnikov.vladi...@gmail.com> wrote:

> > but in this case all these transactions are independent with autocommit
> off,
>
> At database level, there is no "autocommit=off".
> There's just "begin-end".
>
> It is database who forbids .commit, not the JDBC driver.
> Vladimir
>

Re: [GENERAL] [JDBC] JDBC behaviour

[Vladimir Sitnikov]

> but in this case all these transactions are independent with autocommit off,

At database level, there is no "autocommit=off".
There's just "begin-end".

It is database who forbids .commit, not the JDBC driver.
Vladimir


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Re: [GENERAL] [JDBC] JDBC behaviour

[Sridhar N Bamandlapally]

If we want transactions in "begin-end" then its fine,

but in this case all these transactions are independent with autocommit off,

user choice to continue with commit or rollback

Thanks
Sridhar



On Thu, Feb 18, 2016 at 1:43 PM, Vladimir Sitnikov <
sitnikov.vladi...@gmail.com> wrote:

> >Is it a bug or do we have other any alternate way to handle this ?
>
> PostgreSQL is strongly against "partial commits to the database". If
> you think a bit about it, it is not that bad.
> You got an error, what is the business case to commit the partial
> transaction then?
>
> Exceptions should not be used for a "control flow", should they?
>
>
> If you want to shoot yourself in a foot for fun and profit, you can
> try https://github.com/pgjdbc/pgjdbc/pull/477.
> What it does, it creates savepoints before each statement, then it
> rollbacks to that savepoint in case of failure.
>
> Vladimir
>

Re: [GENERAL] [JDBC] JDBC behaviour

[Vladimir Sitnikov]

>Is it a bug or do we have other any alternate way to handle this ?

PostgreSQL is strongly against "partial commits to the database". If
you think a bit about it, it is not that bad.
You got an error, what is the business case to commit the partial
transaction then?

Exceptions should not be used for a "control flow", should they?


If you want to shoot yourself in a foot for fun and profit, you can
try https://github.com/pgjdbc/pgjdbc/pull/477.
What it does, it creates savepoints before each statement, then it
rollbacks to that savepoint in case of failure.

Vladimir


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