topic Re: RepositoryServiceSoapBindingStub.fetchMore() method in Alfresco Archive

RepositoryServiceSoapBindingStub.fetchMore() method

pitt1 — Wed, 07 Mar 2007 17:23:02 GMT

I would like to programmatically grab results from a lucene query in chunks, and furthermore would like to be able to make sure that I can grab all search results. That is, if there are 2950 results and I want to retrieve them in batches of 100, I want to be able to make 30 successive calls to retr

Re: RepositoryServiceSoapBindingStub.fetchMore() method

gblomqui — Mon, 10 Dec 2007 22:19:21 GMT

I'm very surprised that no one has responded to this post. I have also noticed this issue.

I attached a debugger to a locally running Alfresco server (2.0 running on JBoss) and managed to track down what I think is going on.

RepositoryWebService.query delegates to QuerySession.getNextResultsBatch to get the first batch of results based on the given query.

The ResultSetQuerySession.getNextResultsBatch (the ResultSet implementation of the QuerySession interface) method does all the work of assembling the query result set. After it's done building the query result set, it calls AbstractQuerySession.updatePosition. The updatePosition method sets the position instance variable based on the batchSize instance variable. However, the ResultSetQuerySession.getNextResultsBatch method never sets the batchSize instance variable, so position is set to -1.

Later, when you call RepositoryWebService.fetchMore, it too delegates to QuerySession.getNextResultsBatch to get the next batch of results based on the established query. The ResultSetQuerySession.getNextResultsBatch method compares position to -1 and returns null because it believes there is no more data to read. The RepositoryWebService.fetchMore method does not handle a null return value from QuerySession.getNextResultsBatch, thus you get your esoteric error.

I haven't dug into the code enough to determine how easy it is to fix this.

I also have not determined if upgrading to 2.1 fixes this problem.

I also don't know if it's simply something I'm doing wrong that's causing the batchSize instance variable to not be set. I can't immediately tell that this is the problem. But, it could easily be.

Re: RepositoryServiceSoapBindingStub.fetchMore() method

gblomqui — Mon, 10 Dec 2007 22:48:46 GMT

Still digging…

I found that the batchSize is actually set by RepositoryWebService.query by calling Utils.getBatchSize. According to the JavaDoc, that method reads the fetchSize from the QueryConfiguration soap header.

Time to figure out how to send the fetchSize in the QueryConfiguration soap header.

Re: RepositoryServiceSoapBindingStub.fetchMore() method

gblomqui — Tue, 11 Dec 2007 03:23:41 GMT

There's actually a good example of how to set the "fetchSize" in the QueryHeader in one of the repository service tests. Here's what I've got based on that test:

String sQuery = "TYPE:\"" + Constants.TYPE_CONTENT + "\"";

// set the batch size in the query header
int batchSize = 10;
QueryConfiguration queryCfg = new QueryConfiguration();
queryCfg.setFetchSize(batchSize);
RepositoryServiceSoapBindingStub repositoryService = WebServiceFactory.getRepositoryService();
repositoryService.setHeader(new RepositoryServiceLocator().getServiceName().getNamespaceURI(), "QueryHeader", queryCfg);

//  get the first batch of results
QueryResult result = repositoryService.query(STORE, getQuery(sQuery), true);
//process the first query result
String querySession = result.getQuerySession();
while (querySession != null) {
    //  get the next batch of results
    result = repositoryService.fetchMore(querySession);
    // process subsequent query results
    querySession = result.getQuerySession();
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: RepositoryServiceSoapBindingStub.fetchMore() method

kdejaeger — Wed, 16 Apr 2008 15:37:43 GMT

I had problems too with fetchMore. Setting the fetchSize solved the problem.
Apparrently the default batchSize of 1000 in org.alfresco.repo.webservice.Utils is not used since QueryConfigHandler.ALF_FETCH_SIZE is always present (as New Integer(0)). Resulting in a nullpointerexception in RepositoryWebService.

Can somebody verify this? So using fetchMore without setting the fetchSize results in an error. Enable this line in log4j.properties : log4j.logger.org.alfresco.repo.webservice=debug