Decreasing performance when executing consecutive XQuery Update operations

Question

hello,
I am writing an application in java using Berkeley DB XML (2.5.16). I have to run a test over the application, in which a lot of XQuery Update operations have to be executed. All update operations are insert statements. In the beginning the test works fine. However, as the number of updates increases (over 1000 XQuery Updates), there is also a great increase in time of execution. How can I enhance the performance of updates?
Note that:
1) The environment configuration is the following:
EnvironmentConfig envConfig = new EnvironmentConfig();
envConfig.setAllowCreate(true);
envConfig.setInitializeCache(true);
envConfig.setCacheSize(512*1024*1024);
envConfig.setInitializeLocking(false);
envConfig.setInitializeLogging(false);
envConfig.setTransactional(false);
2) No transactions are used
3) The container is a node container
4) Auto-indexing is on (I need that)
5) The container includes only one xml of 2,5MB size.
6) In some insert statements 1000 nodes are to be inserted.
7) I am running windows vista on a 4GB Ram pc.
Thank you in advance,
theo

Answer 1

Hi Lucas,
Thanks a lot for your reply! However, I have a few more questions.
Given that the xml is about 2.5MB size, is it considered to be that big for Berkeley DB so it needs to be break down into smaller documents?
Also, after having executed ~4000 xquery update insert operations and doubled xml’s size, the performance it’s really getting worse… An insertion may even take 1.5 min, when for each of the first 3000 insertions only less than 0.5 sec is needed… Is there something I am missing in the configuration of Berkeley DB? If I set autoindexing off and try to maintain fewer indexes, is it possible to see significantly better performance? Till now I am just getting the following error when I set my indexes and try to execute consequent insertions over the same node:
Exception in thread "main" com.sleepycat.dbxml.XmlException: Error: Sequence does not match type item() - the sequence does not contain items [err:XUDY0027], <query>:1:1, errcode = QUERY_EVALUATION_ERROR+
at com.sleepycat.dbxml.dbxml_javaJNI.XmlQueryExpression_execute__SWIG_1(Native Method)
at com.sleepycat.dbxml.XmlQueryExpression.execute(XmlQueryExpression.java:85)
+<myClasses>+
Thanks,
theo