CODEWITHSUNDEEP
javasolrelasticsearchlucene
rdm
rdm

Reputation: 330

lucene, how use SearcherManager and SearcherLifetimeManager together

In lucene documentation SearcherManager

            IndexSearcher s = manager.acquire();
            try {
              // Do searching, doc retrieval, etc. with s
            } finally {
                manager.release(s);
            }
            // Do not use s after this!
            s = null;

Thus, after search should to release the object and no longer used it. But SearcherLifetimeManager require to store indexsearcher in the internal Map, and then get it:

           long token = mgr.record(searcher);
           IndexSearcher searcher = mgr.acquire(token);
           mgr.release(searcher);

How to use these two approaches together and not break order API calls?

Upvotes: 1

Views: 497

Answers (1)

knutwalker
knutwalker

Reputation: 5974

Basically, you need a token from the user and check, if this token is still valid with the LifetimeManager, otherwise you create a new token with a new IndexSearcher from the SearcherManager. It could look like this:

// Boxed Long, can be null to mean that you might not have a token.
// You could also use Optional or something similar.
Long tokenFromRequest;

// Might be the same as the incoming token or a new one.
Long tokenToReturn;

IndexSearcher is;
if (tokenFromRequest == null) { // no previous token, need a new one
  is = manager.acquire(); // get searcher from SearcherManager
  tokenToReturn = mgr.record(is); // get a fresh token for this searcher
} else {
  is = mgr.acquire(tokenFromRequest); // try to get the recorded searcher
  if (is != null) { // token is valid
    tokenToReturn = tokenFromRequest;
  } else {
    is = manager.acquire(); // get searcher from SearcherManager
    tokenToReturn = mgr.record(is); // get a token for this searcher
  }
}

try {
  // Do searching, doc retrieval, etc. with is
} finally {
  if (tokenToReturn == tokenFromRequest) {
    // token was valid, we need to release the searcher
    // to the LifetimeManager, the SearcherManager had
    // nothing to do with this IndexSearcher
    mgr.release(is);
  } else {
    // we got this searcher from SearcherManager,
    // the LifetimeManager records its usage as well and
    // we need to release it to show that _we_ are finished
    // using it, otherwise it would be kept open forever
    manager.release(is);
  }

}
// Do not use is after this!
is = null;

//return tokenToReturn to user to be sent with the next request

Upvotes: 3

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