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https://issues.apache.org/jira/browse/DERBY-3093?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12535673
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Knut Anders Hatlen commented on DERBY-3093:
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That's a good catch, James! Seems like you have found the bug. If the savepoint
name only needs to be unique within a transaction, I think we can fix it by
maintaining a counter in GenericLanguageConnectionContext and adding a
getUniqueSavepointName() method which returns "ISSP1", "ISSP2", ...
> intermittent transaction failure caused by internal duplicate savepoint name,
> for tirgger
> -----------------------------------------------------------------------------------------
>
> Key: DERBY-3093
> URL: https://issues.apache.org/jira/browse/DERBY-3093
> Project: Derby
> Issue Type: Bug
> Affects Versions: 10.3.1.4
> Environment: Java 1.6.0_02
> Reporter: Jim Newsham
>
> While running our app overnight, performing some intensive database
> operations (primarily deletes), we experienced a transaction failure, with
> error message "A SAVEPOINT with the passed name already exists in the current
> transaction". This failure appears to be very intermittent, as I've run the
> same operation successfully for hours and hours without failure. Some more
> information:
> 1. I see that there are four JIRA issues which report the same message
> (DERBY-2773, DERBY-1457, DERBY-2808, DERBY-2804). I am not sure to what
> extent if any, the problem I experienced is related to these issues.
> • At least three of the above JIRA issues are related to triggers. Our
> transaction failure occurred while performing a delete in a table which has
> delete triggers.
> • We aren't using savepoints explicitly. Of course, it can be seen in
> the stack trace that the trigger operation is setting a savepoint.
> • One of the JIRA issues mentions exceeding maximum depth of nested
> triggers. Not sure what a nested trigger is, but the trigger we are
> performing should not (in theory) cause another trigger event.
> 2. Here's the stack trace:
> Caused by: java.sql.SQLException: A SAVEPOINT with the passed name already
> exists in the current transaction.
> at
> org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown
> Source)
> at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown
> Source)
> at
> org.apache.derby.impl.jdbc.TransactionResourceImpl.wrapInSQLException(Unknown
> Source)
> at
> org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedConnection.handleException(Unknown
> Source)
> at org.apache.derby.impl.jdbc.ConnectionChild.handleException(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(Unknown
> Source)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeStatement(Unknown
> Source)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeUpdate(Unknown
> Source)
> at
> com.referentia.sdf.monitor.samplebase.derby.DerbySampleBase$3.perform(DerbySampleBase.java:682)
> at
> com.referentia.sdf.monitor.samplebase.derby.DerbySampleBase.performInTransaction(DerbySampleBase.java:2747)
> ... 7 more
> Caused by: java.sql.SQLException: A SAVEPOINT with the passed name already
> exists in the current transaction.
> at
> org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
> at
> org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown
> Source)
> ... 18 more
> Caused by: ERROR 3B501: A SAVEPOINT with the passed name already exists in
> the current transaction.
> at org.apache.derby.iapi.error.StandardException.newException(Unknown
> Source)
> at org.apache.derby.impl.store.raw.xact.Xact.setSavePoint(Unknown
> Source)
> at
> org.apache.derby.impl.store.access.RAMTransaction.setSavePoint(Unknown Source)
> at
> org.apache.derby.impl.sql.conn.GenericStatementContext.setSavePoint(Unknown
> Source)
> at org.apache.derby.impl.sql.GenericPreparedStatement.execute(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.GenericTriggerExecutor.executeSPS(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.RowTriggerExecutor.fireTrigger(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.TriggerEventActivator.notifyEvent(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.DeleteResultSet.fireAfterTriggers(Unknown
> Source)
> at org.apache.derby.impl.sql.execute.DeleteResultSet.open(Unknown
> Source)
> at org.apache.derby.impl.sql.GenericPreparedStatement.execute(Unknown
> Source)
> ... 12 more
> 3. Here are the relevant tables and triggers. We have different tables for
> different "sample" data types in our application (currently int, long,
> float, double, Boolean, string). I have shown the int_sample table; the
> other tables are identical but have a different data type for the value
> field.
> Sample records are first class; time records are second class - they only
> exist to support sample records. When there are no remaining sample records
> for a given time record, the time record can be removed. It is the job of
> the trigger to perform this cleanup: when a record is deleted from any of
> the sample tables, the time record corresponding to *_sample.fk_time_id is
> deleted only if there are no remaining records in any of the sample tables
> which have the same fk_time_id. So although there are cascading deletes
> (deleting a time record deletes all of its samples), the trigger should not
> recurse because the trigger only deletes when there are no associated records.
>
> create table time (
> id int not null generated always as identity,
> time timestamp not null,
> constraint time_pk primary key (id),
> constraint time_unique unique (time)
> );
> create table int_sample (
> fk_band_id int not null,
> fk_time_id int not null,
> value int not null,
> constraint int_sample_pk primary key (fk_band_id, fk_time_id),
> constraint int_sample_fk_band foreign key (fk_band_id) references band (id)
> on delete cascade,
> constraint int_sample_fk_time foreign key (fk_time_id) references time (id)
> on delete cascade
> );
> create trigger cascade_delete_unused_time_for_int_sample_trigger
> after delete on int_sample
> referencing old as oldrow
> for each row
> delete from time where
> time.id = oldrow.fk_time_id
> and id not in (select fk_time_id from int_sample)
> and id not in (select fk_time_id from long_sample)
> and id not in (select fk_time_id from float_sample)
> and id not in (select fk_time_id from double_sample)
> and id not in (select fk_time_id from boolean_sample)
> and id not in (select fk_time_id from string_sample);
> 4. Invocation. This is very rough pseudocode focusing on the core logic.
> In reality, there's a lot more code, but I'm doing the usual stuff, such as
> using prepared statements, and closing all resources when done. The key
> thing is that I'm using two statements in a nested fashion; in the outer
> statement, I iterate over records in the time table, and in the inner loop I
> use a second statement to delete records in one of the sample tables. I can
> provide the actual code if desired.
> deleteSamples(int bandId, String sampleTable, Object someQueryCriteria) {
> within transaction {
> create stmt1 iterating over time ids in time table (restricted by
> someQueryCriteria)
> for (time_id in stmt1) {
> PreparedStatement stmt2 = conn.prepareStatement(String.format(
> "delete from %s where fk_band_id = ? and fk_time_id = ?",
> sampleTable));
> set stmt2 parameters and executeUpdate()
> }
> }
> }
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