Database corruption

Carl Hasselskog

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Apr 1, 2012, 9:17:59 AM4/1/12

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Hi,

I have been using H2 for some time now, with great pleasure!

Unfortunately, today I ran into my first database corruption issue. It was during a debugging session, so I had been closing and opening the application quite a lot, which I guess was the cause of the problem. However, I should add that the Exception was thrown after the application had been running for a while during that particular session. The first query that failed was a sum across an entire table so I guess that this caused the corruption to get detected.

The stack-trace looks like this:

org.h2.jdbc.JdbcSQLException: General error: "java.lang.RuntimeException: page[8305] data leaf table:247 TEMP_RESULT_SET_247 entries:0 parent:0 keys:[] offsets:[] parent 0 expected 8139"; SQL statement:

SELECT SUM(DataBlockSize) as TotalSpaceUsed FROM (SELECT avg(dataBlockSize) as DataBlockSize FROM FileDataBlocks WHERE FileVersionIsObsolete = false GROUP BY DataBlockID) [50000-165]

at org.h2.message.DbException.getJdbcSQLException(DbException.java:329) ~[h2-1.3.165.jar:1.3.165]

at org.h2.message.DbException.get(DbException.java:158) ~[h2-1.3.165.jar:1.3.165]

at org.h2.message.DbException.convert(DbException.java:281) ~[h2-1.3.165.jar:1.3.165]

at org.h2.command.Command.executeQuery(Command.java:191) ~[h2-1.3.165.jar:1.3.165]

at org.h2.jdbc.JdbcPreparedStatement.executeQuery(JdbcPreparedStatement.java:96) ~[h2-1.3.165.jar:1.3.165]

I get the following error message when I restart the application:

org.h2.jdbc.JdbcSQLException: File corrupted while reading record: "index not found 249". Possible solution: use the recovery tool [90030-165]

at org.h2.message.DbException.getJdbcSQLException(DbException.java:329)

at org.h2.message.DbException.get(DbException.java:169)

at org.h2.message.DbException.get(DbException.java:146)

at org.h2.store.PageStore.getPage(PageStore.java:765)

at org.h2.index.PageDataIndex.getPage(PageDataIndex.java:226)

at org.h2.index.PageDataNode.getLastKey(PageDataNode.java:208)

at org.h2.index.PageDataIndex.<init>(PageDataIndex.java:83)

at org.h2.table.RegularTable.<init>(RegularTable.java:83)

at org.h2.store.PageStore.addMeta(PageStore.java:1656)

at org.h2.store.PageStore.readMetaData(PageStore.java:1587)

at org.h2.store.PageStore.recover(PageStore.java:1360)

at org.h2.store.PageStore.openExisting(PageStore.java:357)

at org.h2.store.PageStore.open(PageStore.java:281)

at org.h2.engine.Database.getPageStore(Database.java:2118)

at org.h2.engine.Database.open(Database.java:577)

at org.h2.engine.Database.openDatabase(Database.java:222)

at org.h2.engine.Database.<init>(Database.java:217)

at org.h2.engine.Engine.openSession(Engine.java:56)

at org.h2.engine.Engine.openSession(Engine.java:159)

at org.h2.engine.Engine.createSessionAndValidate(Engine.java:138)

at org.h2.engine.Engine.createSession(Engine.java:121)

at org.h2.engine.Engine.createSession(Engine.java:28)

at org.h2.engine.SessionRemote.connectEmbeddedOrServer(SessionRemote.java:305)

at org.h2.jdbc.JdbcConnection.<init>(JdbcConnection.java:110)

at org.h2.jdbc.JdbcConnection.<init>(JdbcConnection.java:94)

at org.h2.Driver.connect(Driver.java:72)

at java.sql.DriverManager.getConnection(DriverManager.java:579)

at java.sql.DriverManager.getConnection(DriverManager.java:221)

The start parameters looked like this:

"C:\Program Files (x86)\Java\jdk1.7.0\bin\java" -agentlib:jdwp=transport=dt_socket,address=127.0.0.1:60036,suspend=y,server=n -server -Xms16m -Xmx1024m -Djavax.net.debug=off -XX:-OmitStackTraceInFastThrow -XX:GCTimeRatio=1 -XX:AdaptiveSizeDecrementScaleFactor=1 -XX:+AggressiveOpts -Dfile.encoding=windows-1252 -classpath [lots of dependencies]

The connection was created with these options: MVCC=TRUE;TRACE_LEVEL_FILE=4;

I have two questions.

1. Do you have any idea on what might have caused this and how I can reduce the probability of it occurring again? I understand that it is hard to say just based on this info.

2. What is the best way to detect and handle database corruption problems like this?

If you need a copy of the database I will gladly provide it.

Kind Regards

Carl Hasselskog

Noel Grandin

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Apr 2, 2012, 9:24:38 AM4/2/12

to h2-da...@googlegroups.com, Carl Hasselskog

You probably want to turn MVCC off, I don't think Thomas has worked all
of the bugs out of that mode.

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Thomas Mueller

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Apr 10, 2012, 2:41:38 AM4/10/12

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Hi,

"C:\Program Files (x86)\Java\jdk1.7.0\bin\java" -agentlib:jdwp=transport=dt_socket,address=127.0.0.1:60036,suspend=y,server=n -server -Xms16m -Xmx1024m -Djavax.net.debug=off -XX:-OmitStackTraceInFastThrow -XX:GCTimeRatio=1 -XX:AdaptiveSizeDecrementScaleFactor=1 -XX:+AggressiveOpts -Dfile.encoding=windows-1252 -classpath [lots of dependencies]

Are you sure you need all those options? Does the problem occur without the performance options, with JDK 6?

> 1. Do you have any idea on what might have caused this and how I can reduce the probability of it occurring again? I understand that it is hard to say just based on this info.

I would like to understand and fix the problem, but to do that I would need a self contained reproducible test case...

> 2. What is the best way to detect and handle database corruption problems like this?

Send a mail :-) Such problems should be fixed.

> If you need a copy of the database I will gladly provide it.

A copy of the database usually isn't enough to reproduce and fix the problem, but it would be a start of course. Could you send me the database file?