![]() If it makes a difference, I added a single non-clustered index to the UniqueId column. You can see the Entity Framework Core logs from the inserts taking place. The only reads I am doing is as part of the insert to retrieve the ID's for the newly created records. Transaction (Process ID 120) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. I'm inserting data into several related tables and occasionally get a SqlException with the following message In practice for most apps, unless this is something serious like a banking app, it doesn't usually matter (and might not even happen at all) unless the connection to the database server is really bad. I strongly advise you to follow the second chapter of this tutorial ("Processing SQL Statements").I'm trying to do a large number of individual inserts containing a large amount of data quickly using Entity Framework Core. AkmalSalikhov For INSERT operations, that is probably possible in rare cases, as long as you don't use a heavier transaction level. Ideally you will call ResultSet.close() as soon as possible to release memory. You never create such an object yourself. Of course if you need to execute another query, then a new PreparedStatement is required.Ī (new) ResultSet object is returned by Statement.executeQuery(), which represents the result of the query. You just need to set new values to your parameters before calling executeQuery() again. Obviously you must not re-create a PreparedStatement between two queries. ![]() So rerunning the transaction may complete successfully. The deadlocks usually last for a very short duration. Should things be running in a loop with a limit to how many times the loop runs?ĭo I re-instantiate PreparedStatement objects? When a transaction fails in SQL Server stored procedure due to deadlock then we can write some logic so that it will rerun the transaction again. Is the exception only thrown after I call mit()?Ī SQLException could be thrown by virtually all methods of all classes from the java.sql package. Yes, see above: SQLException's are the ones, with more information provided by getErrorCode() or getSQLState(). You asked a lot of questions, but I will try to answer them all:Īre there specific exceptions to listen out for? You could also detect that after some errors, there is little hope that another attempt will work (eg. In ODBC API, it's set through the SQLATTRQUERYTIMEOUT attribute in the SQLSetStmtAttr function. NET Framework, the time-out value is set on the CommandTimeout property. You may want to differentiate errors taking place at connection time and errors at execution time. If the time-out value on the application side is set to 0 (no time limit), the Database Engine executes the query until it's completed. Thread.sleep(1000) // short delay before retry When the connection is chosen as a deadlock victim, ExecuteReader () does NOT throw SqlException with 1205 deadlock code for some commands but DOES for others. deadlock or lock-wait time-out occured We're using C SqlCommand.ExecuteReader () to issue SQL Server stored procedure and SQL requests inside a transaction. Rs = s.executeQuery("SELECT stuff FROM mytable") The final code could look like this: boolean oops You should also wait a short amount of time between attemps, so as not to load your server too much.Īs you cleverly guessed, set a maximum number of attempts, or you might end-up in an infinite loop. ![]() For use-case examples of the CommandType. The exception's getSQLState() method provides returns an error code that provides additional information about the actual error. It never completes and I see no exception in the log either. The exception raised when a dead lock occurs is a SQLException. or do I reuse them somehow and close them after the do/while loop? close resources? statement.close(), resultset.close() etc? Same goes for ResultSet objects too.Įdit: I should probably mention that I am working with transactions, setting auto commit to 0 etc.Įdit 2: Am I on the right track with this pseudo code? I have no clue do As I am not sure where things factor in such as, do I re-instantiate PreparedStatement objects or close them first etc etc, it's all very confusing. I essentially just need a bare bones Java code example of how this thing is generally handled. Although I am pretty clued in with the theory and best practices, I am pretty much clueless on how to implement the catch all mechanism of reissuing transactions when a deadlock occurs.Īre there specific exceptions to listen out for? Is the exception only thrown after I call mit() or can it occur as soon as I execute a PreparedStatement? Should things be running in a loop with a limit to how many times the loop runs? I have read quite a bit into InnoDB with Java and how deadlocks can occur no matter what query you are running. I am working on a theory basis here, I want to make sure all my bases are covered.
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