[hibernate-dev] Missing transaction hangs the testsuite

[Steve Ebersole]

For what it is worth, I am running into the same problems on MySQL for the
ORM tests in terms of blocks on dropping tables.  PGSQL at least finishes,
although I run into 55 errors which I still need to triage.

On Thu, Jul 16, 2015 at 5:59 PM Steve Ebersole <steve at hibernate.org> wrote:

> 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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>>
>