[
https://issues.apache.org/jira/browse/DERBY-7116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17343258#comment-17343258
]
Bryan Pendleton commented on DERBY-7116:
----------------------------------------
[Lots of good ideas
here|https://superuser.com/questions/117902/find-out-which-process-is-locking-a-file-or-folder-in-windows],
but they all seem to require (a) being able to reproduce the problem on
demand, and (b) being able to run an interactive tool to examine the running
system to track down the contention.
Sigh.
> Meta-data for unknown could not be accessed to read
> ---------------------------------------------------
>
> Key: DERBY-7116
> URL: https://issues.apache.org/jira/browse/DERBY-7116
> Project: Derby
> Issue Type: Bug
> Components: SQL, Store
> Affects Versions: 10.14.2.0
> Environment: Windows 10
> Reporter: Sam Hutchins
> Priority: Major
>
> Hi,
>
> I'm afraid I don't have a reproducible case for this, but it's an issue we've
> seen in the wild on customer's machines. I'd guess it's specific to Windows,
> as other platforms don't support exclusive locks, and we've only ever seen it
> reported from Windows users.
>
> The `ConcurrentCache` in the stacktrace makes me wonder if Derby is able to
> lock itself out of the database under the right conditions. Here's the trace:
>
> {code:java}
> Caused by: java.sql.SQLException: Meta-data for unknown could not be accessed
> to read
> C:\Users\USER\.ScreamingFrogSEOSpider\ProjectInstanceData\6b422f28-46c9-492e-bbde-aeb5bc1e6307\results_10505723-008c-4b06-aa69-2c676ef858c8\sql\seg0\c71.dat
> at
> org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(SQLExceptionFactory.java)
> at
> org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(SQLExceptionFactory.java)
> at org.apache.derby.impl.jdbc.Util.seeNextException(Util.java)
> at
> org.apache.derby.impl.jdbc.TransactionResourceImpl.wrapInSQLException(TransactionResourceImpl.java)
> at
> org.apache.derby.impl.jdbc.TransactionResourceImpl.handleException(TransactionResourceImpl.java)
> at
> org.apache.derby.impl.jdbc.EmbedConnection.handleException(EmbedConnection.java)
> at
> org.apache.derby.impl.jdbc.ConnectionChild.handleException(ConnectionChild.java)
> at
> org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(EmbedStatement.java)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeStatement(EmbedPreparedStatement.java)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeQuery(EmbedPreparedStatement.java)
> at
> uk.co.screamingfrog.seospider.db.AbstractDuplicateTableOperations.getSpiderUrls(AbstractDuplicateTableOperations.java:152)
> ... 17 more
> Caused by: ERROR XSDG3: Meta-data for unknown could not be accessed to read
> C:\Users\USER\.ScreamingFrogSEOSpider\ProjectInstanceData\6b422f28-46c9-492e-bbde-aeb5bc1e6307\results_10505723-008c-4b06-aa69-2c676ef858c8\sql\seg0\c71.dat
> at
> org.apache.derby.iapi.error.StandardException.newException(StandardException.java)
> at
> org.apache.derby.impl.jdbc.SQLExceptionFactory.wrapArgsForTransportAcrossDRDA(SQLExceptionFactory.java)
> ... 28 more
> Caused by: java.io.FileNotFoundException:
> C:\Users\USER\.ScreamingFrogSEOSpider\ProjectInstanceData\6b422f28-46c9-492e-bbde-aeb5bc1e6307\results_10505723-008c-4b06-aa69-2c676ef858c8\sql\seg0\c71.dat
> (The process cannot access the file because it is being used by another
> process)
> at java.base/java.io.RandomAccessFile.open0(Native Method)
> at java.base/java.io.RandomAccessFile.open(Unknown Source)
> at java.base/java.io.RandomAccessFile.<init>(Unknown Source)
> at java.base/java.io.RandomAccessFile.<init>(Unknown Source)
> at
> org.apache.derby.impl.io.DirRandomAccessFile.<init>(DirRandomAccessFile.java)
> at org.apache.derby.impl.io.DirFile.getRandomAccessFile(DirFile.java)
> at
> org.apache.derby.impl.store.raw.data.RAFContainer.run(RAFContainer.java)
> at java.base/java.security.AccessController.doPrivileged(Native Method)
> at
> org.apache.derby.impl.store.raw.data.RAFContainer.openContainer(RAFContainer.java)
> at
> org.apache.derby.impl.store.raw.data.RAFContainer4.openContainer(RAFContainer4.java)
> at
> org.apache.derby.impl.store.raw.data.FileContainer.setIdent(FileContainer.java)
> at
> org.apache.derby.impl.store.raw.data.FileContainer.setIdentity(FileContainer.java)
> at
> org.apache.derby.impl.services.cache.ConcurrentCache.find(ConcurrentCache.java)
> at
> org.apache.derby.impl.store.raw.data.BaseDataFileFactory.openContainer(BaseDataFileFactory.java)
> at
> org.apache.derby.impl.store.raw.data.BaseDataFileFactory.openContainer(BaseDataFileFactory.java)
> at org.apache.derby.impl.store.raw.xact.Xact.openContainer(Xact.java)
> at
> org.apache.derby.impl.store.access.btree.OpenBTree.init(OpenBTree.java)
> at
> org.apache.derby.impl.store.access.btree.BTreeScan.init(BTreeScan.java)
> at
> org.apache.derby.impl.store.access.btree.index.B2IForwardScan.init(B2IForwardScan.java)
> at org.apache.derby.impl.store.access.btree.index.B2I.openScan(B2I.java)
> at
> org.apache.derby.impl.store.access.RAMTransaction.openScan(RAMTransaction.java)
> at
> org.apache.derby.impl.store.access.RAMTransaction.openScan(RAMTransaction.java)
> at
> org.apache.derby.impl.sql.catalog.DataDictionaryImpl.getDescriptorViaIndexMinion(DataDictionaryImpl.java)
> at
> org.apache.derby.impl.sql.catalog.DataDictionaryImpl.getDescriptorViaIndex(DataDictionaryImpl.java)
> at
> org.apache.derby.impl.sql.catalog.DataDictionaryImpl.getTableDescriptorIndex1Scan(DataDictionaryImpl.java)
> at
> org.apache.derby.impl.sql.catalog.DataDictionaryImpl.getUncachedTableDescriptor(DataDictionaryImpl.java)
> at
> org.apache.derby.impl.sql.catalog.NameTDCacheable.setIdentity(NameTDCacheable.java)
> at
> org.apache.derby.impl.services.cache.ConcurrentCache.find(ConcurrentCache.java)
> at
> org.apache.derby.impl.sql.catalog.DataDictionaryImpl.getTableDescriptor(DataDictionaryImpl.java)
> at
> org.apache.derby.impl.sql.compile.QueryTreeNode.getTableDescriptor(QueryTreeNode.java)
> at
> org.apache.derby.impl.sql.compile.FromBaseTable.bindTableDescriptor(FromBaseTable.java)
> at
> org.apache.derby.impl.sql.compile.FromBaseTable.bindNonVTITables(FromBaseTable.java)
> at org.apache.derby.impl.sql.compile.FromList.bindTables(FromList.java)
> at
> org.apache.derby.impl.sql.compile.SelectNode.bindNonVTITables(SelectNode.java)
> at
> org.apache.derby.impl.sql.compile.DMLStatementNode.bindTables(DMLStatementNode.java)
> at
> org.apache.derby.impl.sql.compile.DMLStatementNode.bind(DMLStatementNode.java)
> at
> org.apache.derby.impl.sql.compile.CursorNode.bindStatement(CursorNode.java)
> at
> org.apache.derby.impl.sql.GenericStatement.prepMinion(GenericStatement.java)
> at
> org.apache.derby.impl.sql.GenericStatement.prepare(GenericStatement.java)
> at
> org.apache.derby.impl.sql.GenericPreparedStatement.rePrepare(GenericPreparedStatement.java)
> at
> org.apache.derby.impl.sql.GenericPreparedStatement.executeStmt(GenericPreparedStatement.java)
> at
> org.apache.derby.impl.sql.GenericPreparedStatement.execute(GenericPreparedStatement.java)
> ... 21 more {code}
>
> The exception message mentions "another process", but it's possible to get
> exactly this error message in a single Java application:
>
> {code:java}
> public static void main(
> final String[] args) throws Exception
> {
> final Path path = Path.of("lock");
> path.toFile().createNewFile();
> try (final FileChannel channel = FileChannel.open(path,
> StandardOpenOption.APPEND))
> {
> channel.lock(0, Long.MAX_VALUE, false);
> System.out.println("Locked");
> final FileInputStream fis = new FileInputStream(path.toFile());
> fis.readAllBytes();
> System.out.println("Done");
> }
> } {code}
>
> On Windows, this will throw a similar exception.
>
> If, however, it is a problem caused by some other piece of software (such as
> antivirus or backup software), is there a way for Derby to use this same
> locking mechanism to lock out those other applications?
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
