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From Daniel John Debrunner <...@debrunners.com>
Subject Re: [Derby-359]Skipping over user inserted values into GENERATED BY DEFAULT identity columns....
Date Fri, 23 Dec 2005 16:41:18 GMT
Mamta Satoor wrote:
> I looked at Derby code and in fact, Derby does implement the SQL
> standard by doing the job of getting the generated value and updating
> the system table SYSCOLUMNS for the next generated value in a
> transaction of its own. But this does not happen in its own transaction
> when there are lock issues on the system table.
> If we run the problem script that Satheesh has provided in JIRA for this
> bug with autocommit on, we will have the expected behavior of Derby
> consuming the generated value even if the insert fails for duplicate
> key. But if the same script is run with autocommit off, the create
> unique index sql puts a table lock on SYSCOLUMNS table. Next when the
> insert is run with a request for system to generate a value, Derby
> starts a new transaction in InsertResultSet.getSetAutoincrementValue at
> line 777. At line 794, it calls DataDictionary.getSetAutoincrementValue
> method to do the actual job of generating the value and updating the
> system table. But because the user(parent) transaction has table lock on
> SYSCOLUMNS, <snip>

The troubling item here is that you say create index is getting a table
lock on SYSCOLUMNS. Is a create index on another table by another
transaction going to cause the same issue?

Is it the create index or the create table that is leading to the lock


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