Re: [firebird-support] Re: Can many Execute Blocks be within a Transaction.
13.03.2018 9:30, Mark Rotteveel m...@lawinegevaar.nl [firebird-support] wrote: > and in Firebird 3 when using the old API (most applications use > the old API). Actually 64k limit is applied to statement in ISC API only if length of statement is indicated explicitly and function declarations are unmodified. Otherwise it is the same as in the new API. -- WBR, SD. ++ Visit http://www.firebirdsql.org and click the Documentation item on the main (top) menu. Try FAQ and other links from the left-side menu there. Also search the knowledgebases at http://www.ibphoenix.com/resources/documents/ ++ Yahoo Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/firebird-support/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/firebird-support/join (Yahoo! ID required) <*> To change settings via email: firebird-support-dig...@yahoogroups.com firebird-support-fullfeatu...@yahoogroups.com <*> To unsubscribe from this group, send an email to: firebird-support-unsubscr...@yahoogroups.com <*> Your use of Yahoo Groups is subject to: https://info.yahoo.com/legal/us/yahoo/utos/terms/
Re: [firebird-support] Re: Can many Execute Blocks be within a Transaction.
On 13-3-2018 02:12, ho...@agencybusys.com [firebird-support] wrote: > Thank you, Mark, for such a complete and clear answer. You are a big > help to me. What you said agrees and helps me understand what I have > read. What I was concerned about was my Execute Blocks were too big, and > had to be split into several smaller blocks. I wanted to make sure all > the blocks were executed as a single transaction to keep other users > from interleaving their updates. You have answered that question quite > nicely. Thanks again. That size limit is the maximum size of 64 kilobyte for statements. This limit applies to all statement types, and exists in Firebird 2.5 and earlier, and in Firebird 3 when using the old API (most applications use the old API). In the new API, the limit has been raised to 10 megabyte. Mark -- Mark Rotteveel
[firebird-support] Re: Can many Execute Blocks be within a Transaction.
Thank you, Mark, for such a complete and clear answer. You are a big help to me. What you said agrees and helps me understand what I have read. What I was concerned about was my Execute Blocks were too big, and had to be split into several smaller blocks. I wanted to make sure all the blocks were executed as a single transaction to keep other users from interleaving their updates. You have answered that question quite nicely. Thanks again.
[firebird-support] Re: Can many Execute Blocks be within a Transaction.
Thank you Karol, I did not want Parallel, so good news.
Re: [firebird-support] Re: Can many Execute Blocks be within a Transaction.
On 2018-03-12 18:08, ho...@agencybusys.com [firebird-support] wrote: > I didn't see a way to edit the previous post, so sorry for this > afterthought. > > My concert are: > > 1. Since the EBs are executed on the Server, will a transaction > created in Delphi have any benefit for controlling the sequence of > execution, or the ability to roll back if a failure occurs in block An execute block is 'simply' an anonymous stored procedure, so it works the same as executing stored procedures. And just like stored procedures (or any other statement in Firebird), they need to be executed within a transaction (your Delphi component likely starts on implicitly if you haven't started one explicitly), and just like stored procedures (or other statements) it is possible to run more than one in a single transaction. So yes, you can start a transaction and run multiple execute blocks in them, and roll back will roll back all executed blocks (assuming you don't use IN AUTONOMOUS TRANSACTION DO within your execute block). > 2-n. > 2. Once the EBs are submitted to the server, is there any way to > control the order in which they execute. In other words, are they > executed in serial or parallel. If your EXECUTE BLOCK does not contain any SUSPEND statements, then your application will be blocked until it is complete; control is only returned when execution is done. If your EXECUTE BLOCK has SUSPEND statements, then you should not forget to fetch all rows, otherwise it will not have any effect (this is the same as when executing executable vs selectable stored procedures). So, without SUSPEND execute block is complete after execute is done and it cannot be executed in parallel. If your execute block has SUSPEND, you can interleave fetches between the different blocks, although I suggest you don't do that, because in general that would lead to hard to follow code (and consume more resources). However, even here, only one statement is 'active' at a time (so it is concurrent, but not parallel). > 3. Do I need to do anything to handle deadlocks if they are executed > in parallel. Given they are not executed in parallel, and share the same transaction, it should not be possible for deadlocks to occur. Mark
Re: [firebird-support] Re: Can many Execute Blocks be within a Transaction.
Hi, One transaction have benefits like integrity. If your process must be accomplished as a whole it is only good way for this. Your statments are executed serial. For parallel you will need many connections at the same time. Regards,Karol Bieniaszewski null
[firebird-support] Re: Can many Execute Blocks be within a Transaction.
I didn't see a way to edit the previous post, so sorry for this afterthought. My concert are: 1. Since the EBs are executed on the Server, will a transaction created in Delphi have any benefit for controlling the sequence of execution, or the ability to roll back if a failure occurs in block 2-n. 2. Once the EBs are submitted to the server, is there any way to control the order in which they execute. In other words, are they executed in serial or parallel. 3. Do I need to do anything to handle deadlocks if they are executed in parallel.
