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Posted to derby-dev@db.apache.org by "Dag H. Wanvik (JIRA)" <ji...@apache.org> on 2008/05/28 02:23:45 UTC
[jira] Commented: (DERBY-3693) Deadlocks accessing DB metadata
[ https://issues.apache.org/jira/browse/DERBY-3693?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12600322#action_12600322 ]
Dag H. Wanvik commented on DERBY-3693:
--------------------------------------
Are are able to produce a repro program for this? I tried to make one based on your explanations, but no luck yet.
>From what you say, the problem is intermittent, so presumably more than one connection makes the
metadata queries? What isolation level are you running with? (default is read committed).
Is there more information in derby.log? Did the deadlock dump only show the victim?
> Deadlocks accessing DB metadata
> -------------------------------
>
> Key: DERBY-3693
> URL: https://issues.apache.org/jira/browse/DERBY-3693
> Project: Derby
> Issue Type: Bug
> Components: JDBC
> Affects Versions: 10.3.2.1, 10.3.3.0, 10.4.1.3
> Environment: Linux amd64 or Windows 32bit
> Reporter: Svata Dedic
>
> My code changes DB structure (create a column), then immediately after setting autocommit back to true, the code rescans the DB metadata
> DatabaseMetaData.getColumns(catalog, schemaName, tableName, null);
> I am sometimes getting a deadlock with these operations:
> 2008-04-16 19:50:47.833 GMT Thread[Default RequestProcessor,1,system] (XID = 569844), (SESSIONID = 2), (DATABASE = /..../a3/.config/localdb/db), (DRDAID = null), Cleanup action starting 2008-04-16 19:50:47.833 GMT Thread[Default RequestProcessor,1,system] (XID = 569844), (SESSIONID = 2), (DATABASE = /..../IJCProjects/a3/.config/localdb/db), (DRDAID = null), Failed Statement is: EXECUTE STATEMENT SYS."getColumns" ERROR 40XL2: A lock could not be obtained within the time requested.
> The lockTable dump is:
> 2008-04-16 19:50:47.796 GMT
> XID |TYPE |MODE|LOCKCOUNT|LOCKNAME |STATE|TABLETYPE /LOCKOBJ |INDEXNAME / CONTAINER_ID / MODE for LATCH only) |TABLENAME / CONGLOM_ID |
> ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
> *** The following row is the victim ***
> 569852 |ROW |X |0 |(44,7) |WAIT |S |NULL |SYSSTATEMENTS |
> *** The above row is the victim ***
> The stacktrace of the operation causing the deadlock is
> at org.apache.derby.iapi.error.StandardException.newException(Unknown Source)
> at org.apache.derby.impl.services.locks.Timeout.createException(Unknown Source)
> at org.apache.derby.impl.services.locks.Timeout.buildException(Unknown Source)
> at org.apache.derby.impl.services.locks.ConcurrentLockSet.lockObject(Unknown Source)
> at org.apache.derby.impl.services.locks.AbstractPool.lockObject(Unknown Source)
> at org.apache.derby.impl.services.locks.ConcurrentPool.lockObject(Unknown Source)
> at org.apache.derby.impl.store.raw.xact.RowLocking3.lockRecordForWrite(Unknown Source)
> at org.apache.derby.impl.store.access.heap.HeapController.lockRow(Unknown Source)
> at org.apache.derby.impl.store.access.heap.HeapController.lockRow(Unknown Source)
> at org.apache.derby.impl.store.access.btree.index.B2IRowLocking3.lockRowOnPage(Unknown Source)
> at org.apache.derby.impl.store.access.btree.index.B2IRowLocking3._lockScanRow(Unknown Source)
> at org.apache.derby.impl.store.access.btree.index.B2IRowLockingRR.lockScanRow(Unknown Source)
> at org.apache.derby.impl.store.access.btree.BTreeForwardScan.fetchRows(Unknown Source)
> at org.apache.derby.impl.store.access.btree.BTreeScan.fetchNext(Unknown Source)
> at org.apache.derby.impl.sql.catalog.TabInfoImpl.updateRow(Unknown Source)
> at org.apache.derby.impl.sql.catalog.TabInfoImpl.updateRow(Unknown Source)
> at org.apache.derby.impl.sql.catalog.DataDictionaryImpl.updateSPS(Unknown Source )
> at org.apache.derby.iapi.sql.dictionary.SPSDescriptor.updateSYSSTATEMENTS(Unknown Source)
> at org.apache.derby.iapi.sql.dictionary.SPSDescriptor.getPreparedStatement(Unknown Source)
> at org.apache.derby.iapi.sql.dictionary.SPSDescriptor.getPreparedStatement(Unknown Source)
> at org.apache.derby.impl.sql.compile.ExecSPSNode.generate(Unknown Source)
> at org.apache.derby.impl.sql.GenericStatement.prepMinion(Unknown Source)
> at org.apache.derby.impl.sql.GenericStatement.prepare(Unknown Source)
> at org.apache.derby.impl.sql.GenericPreparedStatement.rePrepare(Unknown Source)
> at org.apache.derby.impl.sql.GenericPreparedStatement.execute(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.executeQuery(Unknown Source)
> at org.apache.derby.impl.jdbc.EmbedDatabaseMetaData.doGetCols(Unknown Source)
> at org.apache.derby.impl.jdbc.EmbedDatabaseMetaData.getColumns(Unknown Source)
> I've seen the deadlock occur during several get-metadata operations (getImportedKeys, ...), each time waiting on the SYSSTATEMENTS apparently because of internally constructed PreparedStatement. The lock eventually times out and the locked out operation completes without error.
> When the deadlock occurs, the "real" SQL into systables is being compiled (I traced this sql to be the value of "getColumns" key in org/apache/derby/impl/jdbc/metadata.properties file):
> ---------%<-----------------------%<--------------
> Begin compiling prepared statement: SELECT CAST ('' AS VARCHAR(128)) AS PKTABLE_CAT, S.SCHEMANAME AS PKTABLE_SCHEM, TABLENAME AS
> PKTABLE_NAME, COLS.COLUMNNAME AS PKCOLUMN_NAME, CAST ('' AS VARCHAR(128)) AS FKTABLE_CAT, FKTABLE_SCHEM, FKTABLE_NAME, FKCOLUMN_NAME, CAST ...
> ---------%<-----------------------%<--------------
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