[hibernate-dev] Missing transaction hangs the testsuite

Thu Jul 16 18:59:23 EDT 2015

There is really nothing to improve.  What would you suggest as an
improvement?  I mean from a ORM perspective, we have an auto-commit
Connection (presumably) and run a query.  How on earth would we know to
expect that the database is holding locks for that?

As far as "requiring transactions" I have tried to fly that plane multiple
times in the past.  I think it is absolutely ridiculous to allow these
auto-commit use cases.  In fact I personally wanted to take it to the more
extreme case of always using JTA and simply mimicking "single resource
JTA transactions"
internally in the "JDBC transaction" case.  Gavin and I both did in fact.
But we got a lot of push back.

So I am not sure exactly what the improvement here might be.  What is it
you were thinking specifically?

On Thu, Jul 16, 2015 at 5:36 PM Sanne Grinovero <sanne at hibernate.org> wrote:

> I finally got to re-enable MariaDB and PostgreSQL based tests for
> Hibernate Search - which has been running on H2 only for some months -
> and had to debug a case of a single test hanging for a long time.
>
> Essentially it would block - for hours - on the SessionFactory#close()
> method, attempting to drop the database schema with the following
> statement:
>   > alter table AncientBook_alternativeTitles drop constraint
> FKn8hhkmhof1mdgc4oi77ccq989
>
> Dumping threads I would get a very similar stack trace on both
> databases; initially I thought someone had copy/pasted a socket
> handling bug from one JDBC driver to the other ;-)
>
> The PostgreSQL testsuite hanging:
>
> "main" prio=10 tid=0x00007f0f40009000 nid=0x5f7c runnable
> [0x00007f0f48956000]
>    java.lang.Thread.State: RUNNABLE
> at java.net.SocketInputStream.socketRead0(Native Method)
> at java.net.SocketInputStream.read(SocketInputStream.java:152)
> at java.net.SocketInputStream.read(SocketInputStream.java:122)
> at
> org.postgresql.core.VisibleBufferedInputStream.readMore(VisibleBufferedInputStream.java:145)
> at
> org.postgresql.core.VisibleBufferedInputStream.ensureBytes(VisibleBufferedInputStream.java:114)
> at
> org.postgresql.core.VisibleBufferedInputStream.read(VisibleBufferedInputStream.java:73)
> at org.postgresql.core.PGStream.ReceiveChar(PGStream.java:274)
> at
> org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1660)
> at
> org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
> - locked <0x00000007c11e3860> (a org.postgresql.core.v3.QueryExecutorImpl)
> at
> org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:500)
> at
> org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:374)
> at
> org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:302)
> at
> org.hibernate.tool.hbm2ddl.DatabaseExporter.export(DatabaseExporter.java:47)
> at org.hibernate.tool.hbm2ddl.SchemaExport.perform(SchemaExport.java:476)
> at org.hibernate.tool.hbm2ddl.SchemaExport.execute(SchemaExport.java:430)
> at org.hibernate.tool.hbm2ddl.SchemaExport.drop(SchemaExport.java:375)
> at org.hibernate.tool.hbm2ddl.SchemaExport.drop(SchemaExport.java:371)
> at
> org.hibernate.internal.SessionFactoryImpl.close(SessionFactoryImpl.java:1069)
> at
> org.hibernate.search.test.util.FullTextSessionBuilder.close(FullTextSessionBuilder.java:149)
> at
> org.hibernate.search.test.util.FullTextSessionBuilder$1.evaluate(FullTextSessionBuilder.java:248)
> at org.junit.rules.RunRules.evaluate(RunRules.java:20)
> at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
> at
> org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264)
> at
> org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
> at
> org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124)
> at
> org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200)
> at
> org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153)
> at
> org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)
>
> The MariaDB testsuite hanging:
>
> "main" prio=10 tid=0x00007f8ca0009000 nid=0x4043 runnable
> [0x00007f8ca5f5c000]
>    java.lang.Thread.State: RUNNABLE
> at java.net.SocketInputStream.socketRead0(Native Method)
> at java.net.SocketInputStream.read(SocketInputStream.java:152)
> at java.net.SocketInputStream.read(SocketInputStream.java:122)
> at
> com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:114)
> at
> com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:161)
> at
> com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:189)
> - locked <0x00000007c0baa518> (a com.mysql.jdbc.util.ReadAheadInputStream)
> at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2499)
> at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2952)
> at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2941)
> at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3489)
> at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)
> at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2113)
> at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2562)
> - locked <0x00000007c0baa850> (a java.lang.Object)
> at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1664)
> - locked <0x00000007c0baa850> (a java.lang.Object)
> at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1583)
> at
> org.hibernate.tool.hbm2ddl.DatabaseExporter.export(DatabaseExporter.java:47)
> at org.hibernate.tool.hbm2ddl.SchemaExport.perform(SchemaExport.java:476)
> at org.hibernate.tool.hbm2ddl.SchemaExport.execute(SchemaExport.java:430)
> at org.hibernate.tool.hbm2ddl.SchemaExport.drop(SchemaExport.java:375)
> at org.hibernate.tool.hbm2ddl.SchemaExport.drop(SchemaExport.java:371)
> at
> org.hibernate.internal.SessionFactoryImpl.close(SessionFactoryImpl.java:1069)
> at
> org.hibernate.search.test.util.FullTextSessionBuilder.close(FullTextSessionBuilder.java:149)
> at
> org.hibernate.search.test.util.FullTextSessionBuilder$1.evaluate(FullTextSessionBuilder.java:248)
> at org.junit.rules.RunRules.evaluate(RunRules.java:20)
> at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
> at
> org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264)
> at
> org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
> at
> org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124)
> at
> org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200)
> at
> org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153)
> at
> org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)
>
> On Gail's suggestion I went looking for database level locks; I hadn't
> thought of that as I assumed it would have timed out more aggressively
> rather than have me wait for hours.
> It turns out she was right and the reason for blocking was a simple
> "count *" query being run as a post-test assertion, which we had
> forgotten to wrap in an "open transaction & commit" statements pair.
> The test assertion would be successful, but apparently it would hold
> on the table lock beyond closing the Session and, then fail to drop
> the database at the teardown of the test.
>
> I'm wondering if this is expected, or if there's something in the new
> transaction handling code which could be improved? It took me several
> hours to figure this out; maybe I'm just not using ORM as frequently
> as once :)
> If it's this critical to have the transaction, maybe it should be
> mandatory?
>
> And as a memo for next time, this is the query to figure out details
> about locks on our testing db:
>  > SELECT * FROM pg_locks pl LEFT JOIN pg_stat_activity psa ON pl.pid
> = psa.pid where datname = 'testingdb';
>
> Thanks,
> Sanne
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