Problem using secondary database, sequence (and custom tuple binding)

Question

I get an exception when I try to open a Sequence to a database that has a custom tuple binding and a secondary database. I have a guess what the issue is (below), but it boils down to my custom tuple-binding being invoked when opening the sequence. Here is the exception:
java.lang.IndexOutOfBoundsException
at com.sleepycat.bind.tuple.TupleInput.readUnsignedInt(TupleInput.java:4
14)
at com.sleepycat.bind.tuple.TupleInput.readInt(TupleInput.java:233)
at COM.shopsidekick.db.community.Shop_URLTupleBinding.entryToObject(Shop
_URLTupleBinding.java:72)
at com.sleepycat.bind.tuple.TupleBinding.entryToObject(TupleBinding.java
:73)
at COM.tagster.db.community.SecondaryURLKeyCreator.createSecondaryKey(Se
condaryURLKeyCreator.java:38)
at com.sleepycat.je.SecondaryDatabase.updateSecondary(SecondaryDatabase.
java:546)
at com.sleepycat.je.SecondaryTrigger.databaseUpdated(SecondaryTrigger.ja
va:42)
at com.sleepycat.je.Database.notifyTriggers(Database.java:1343)
at com.sleepycat.je.Cursor.putInternal(Cursor.java:770)
at com.sleepycat.je.Cursor.putNoOverwrite(Cursor.java:352)
at com.sleepycat.je.Sequence.<init>(Sequence.java:139)
at com.sleepycat.je.Database.openSequence(Database.java:332)
Here is my code:
// URL ID DB
DatabaseConfig urlDBConfig = new DatabaseConfig();
urlDBConfig.setAllowCreate(true);
urlDBConfig.setReadOnly(false);
urlDBConfig.setTransactional(true);
urlDBConfig.setSortedDuplicates(false); // No sorted duplicates (can't have them with a secondary DB)
mURLDatabase = mDBEnv.openDatabase(txn, "URLDatabase", urlDBConfig);
// Reverse URL lookup DB table
SecondaryConfig secondaryURLDBConfig = new SecondaryConfig();
secondaryURLDBConfig.setAllowCreate(true);
secondaryURLDBConfig.setReadOnly(false);
secondaryURLDBConfig.setTransactional(true);
TupleBinding urlTupleBinding = DataHelper.instance().createURLTupleBinding();
SecondaryURLKeyCreator secondaryURLKeyCreator = new SecondaryURLKeyCreator(urlTupleBinding);
secondaryURLDBConfig.setKeyCreator(secondaryURLKeyCreator);
mReverseLookpupURLDatabase = mDBEnv.openSecondaryDatabase(txn, "SecondaryURLDatabase", mURLDatabase, secondaryURLDBConfig);
// Open the URL ID sequence
SequenceConfig urlIDSequenceConfig = new SequenceConfig();
urlIDSequenceConfig.setAllowCreate(true);
urlIDSequenceConfig.setInitialValue(1);
mURLSequence = mURLDatabase.openSequence(txn, new DatabaseEntry(URLID_SEQUENCE_NAME.getBytes("UTF-8")), urlIDSequenceConfig);
My secondary key creator class looks like this:
public class SecondaryURLKeyCreator implements SecondaryKeyCreator {
// Member variables
private TupleBinding mTupleBinding; // The tuple binding
* Constructor.
public SecondaryURLKeyCreator(TupleBinding iTupleBinding) {
mTupleBinding = iTupleBinding;
* Create the secondary key.
public boolean createSecondaryKey(SecondaryDatabase iSecDB, DatabaseEntry iKeyEntry, DatabaseEntry iDataEntry, DatabaseEntry oResultEntry) {
try {
URLData urlData = (URLData)mTupleBinding.entryToObject(iDataEntry);
String URL = urlData.getURL();
oResultEntry.setData(URL.getBytes("UTF-8"));
catch (IOException willNeverOccur) {
// Success
return(true);
I think I understand what is going on, and I only noticed it now because I added more fields to my custom data (and tuple binding):
com.sleepycat.je.Sequence.java line 139 (version 3.2.44) does this:
status = cursor.putNoOverwrite(key, makeData());
makeData creates a byte array of size MAX_DATA_SIZE (50 bytes) -- which has nothing to do with my custom data.
The trigger causes an call to SecondaryDatable.updateSecondary(...) to the secondary DB.
updateSecondary calls createSecondaryKey in my SecondaryKeyCreator, which calls entityToObject() in my tuple-binding, which calls TupleInput.readString(), etc to match my custom data. Since what is being read goes for more than the byte array of size 50, I get the exception.
I didn't notice before because my custom tuple binding used to read fewer that 50 bytes.
I think the problem is that my tuple binding is being invoked at all at this point -- opening a sequence -- since there is no data on which it can act.

Answer 1

Hi,
It looks like you're making a common mistake with sequences which is to store the sequence itself in a database that is also used for application data. The sequence should normally be stored in separate database to prevent configuration conflicts and actual data conflicts between the sequence record and the application records.
I suggest that you create another database whose only purpose is to hold the sequence record. This database will contain only a single record -- the sequence. If you have more than one sequence, storing all sequences in the same database makes sense and is safe.
The database used for storing sequences should not normally have any associated secondary databases and should not be configured for duplicates.
--mark