Обсуждение: Transaction size limit & Data Truncation
Hello, I use the PostgreSQL 7.0.2 JDBC Driver. I can see that very long transaction are not supported. Is there any limit in the transaction size? My second querstion is about data truncation. As I can see postgresql JDBC driver doesn't report a DataTruncation warning when a data value is truncated. Is there any other way to detect data truncation? Thanks in advance for your help. Best Regards, Sofia Alexaki
Alexaki, I am unsure what you mean by very long transaction. A transaction is defined by issueing a 'begin' statement, followed sometime later by a 'commit' or 'rollback'. Therefore a long transcation would imply a long period of time between the begin and the commit or rollback. There is no limit that I am aware of on the length in time for a transaction. My guess is that you mean by 'long transaction' is really 'long statement'. In postgres versions prior to 7.0 the server had an 8k limit on statement/query length. That was removed in 7.0, however the 7.0 jdbc driver still had the limit. I believe the 7.0.3 jdbc driver finally removed the 8K statement length limit and it is certainly removed in the 7.1 driver. On your second questions, what sort of data truncation are you talking about? Could you provide an example? thanks, --Barry Alexaki Sofia wrote: > Hello, > > I use the PostgreSQL 7.0.2 JDBC Driver. > > I can see that very long transaction are not supported. Is there any > limit in the transaction size? > > My second querstion is about data truncation. As I can see postgresql > JDBC driver doesn't report a DataTruncation warning when a data > value is truncated. Is there any other way to detect data truncation? > > Thanks in advance for your help. > > Best Regards, > Sofia Alexaki > > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) > >
Thanks for your reply. As far as transaction is concerned, my question was if there is any limit to the number of statements (select/insert/update) that can be in one single transaction. Is is possible postgresql buffer size influence transaction limit? I had a transaction with thousands of statements that I neeeded to split it into a number smaller transaction in order to be able to store it. >I am unsure what you mean by very long transaction. A transaction is >defined by issueing a 'begin' statement, followed sometime later by a >'commit' or 'rollback'. Therefore a long transcation would imply a long >period of time between the begin and the commit or rollback. There is >no limit that I am aware of on the length in time for a transaction. >n your second questions, what sort of data truncation are you talking >about? Could you provide an example? Let's say that I have a field in a table having tha type VARCHAR(100) And I store to this field a value having 200 characters. Only the first 100 characters of the value will be stored. I think that in this case according to JDBC, a Data Truncation warning should be reported. Alexaki Sofia wrote: > Hello, > > I use the PostgreSQL 7.0.2 JDBC Driver. > > I can see that very long transaction are not supported. Is there any > limit in the transaction size? > > My second querstion is about data truncation. As I can see postgresql > JDBC driver doesn't report a DataTruncation warning when a data > value is truncated. Is there any other way to detect data truncation? > > Thanks in advance for your help.
You wrote: >> I can see that very long transaction are not supported. Where or how did you see that? >As far as transaction is concerned, my question was if there is any limit >to the number of statements (select/insert/update) that can be >in one single transaction. >Is is possible postgresql buffer size influence transaction >limit? >I had a transaction with thousands of statements that I neeeded >to split it into a number smaller transaction in order to be able to >store it. What does that mean exactly? What went wrong with the original long transaction? Was it an executeBatch() with a lot of statements, or a lot of individual statements? What version of the PostgreSQL driver and backend are you running? >Let's say that I have a field in a table having tha type VARCHAR(100) >And I store to this field a value having 200 characters. Only the >first 100 characters of the value will be stored. >I think that in this case according to JDBC, a Data Truncation warning >should be reported. Our driver does not yet support DataTruncation warnings. That's documented on http://lab.applinet.nl/postgresql-jdbc/ Regards, René Pijlman <rene@lab.applinet.nl>