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https://issues.apache.org/jira/browse/DERBY-3693?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Knut Anders Hatlen resolved DERBY-3693.
---------------------------------------
Resolution: Fixed
Filed remaining tasks as DERBY-3850. Marking this bug as resolved.
> 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
> Assignee: Knut Anders Hatlen
> Fix For: 10.4.2.0, 10.5.0.0
>
> Attachments: comments.diff, d3693.java, deadlock.diff, derby.log,
> dontWait.diff, dontWait.stat, GetTables.java, nested_transaction.diff,
> nested_transaction_v2.diff
>
>
> 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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