Most likely you're hitting this issue:
https://issues.apache.org/jira/browse/LUCENE-1316
Which is fixed in 2.9. Can you try running with 2.9 to confirm?
Mike
On Thu, Aug 6, 2009 at 8:19 AM, Carl Austin<carl.aus...@detica.com> wrote:
> Hi,
>
> I have been seeing an issue running MatchAllDocsQueries concurrently.
> Running one against a test index is very fast (70 ms). Running two
> concurrently can take 5-25 seconds on the same test index! This issue
> doesn't occur with any other type of query I have used.
> Because of this, I have put together a few test classes to demonstrate
> this in a simple manner. These recreate the issue with only the most
> basic Lucene api usage.
>
> I have incldued the code for the classes below in this email. Just run
> TestIndexCreator with a single argument of where to create the test
> index. This will create an index with 999999 documents in, each document
> having only 1 field with the value "testing" in that field. Only one
> unique term for the whole index.
> Then run the class Test with the same argument as the index creator.
> This will run a 4 tests with a 5 second wait between each. The first
> runs a single term query for "testing". The second a single match all
> docs query. The third 2 concurrent term queries and the fourth 2
> concurrent match all docs queries. It is the fourth that takes a
> relatively long time to complete.
> On a larger index I have here it can take 8 minutes to run just 2 match
> all docs queries concurrently.
>
> I look forward to hearing further on this. I can provide this in Jar for
> if wished, though I don't know if you can attach to these emails.
>
> Thanks
>
> Carl
>
>
> Source Code:
>
> import org.apache.lucene.analysis.KeywordAnalyzer;
> import org.apache.lucene.document.Document;
> import org.apache.lucene.document.Field;
> import org.apache.lucene.document.Field.Index;
> import org.apache.lucene.document.Field.Store;
> import org.apache.lucene.index.IndexReader;
> import org.apache.lucene.index.IndexWriter;
>
>
> public class TestIndexCreator {
>
>
> public static void main(String[] args) throws Exception
> {
> if (!IndexReader.indexExists(args[0]))
> {
> IndexWriter w = new IndexWriter(args[0], new
> KeywordAnalyzer(), true);
> for(int i =0; i < 1000000; i++)
> {
> Document doc = new Document();
> doc.add(new Field("testfield",
> "testing", Store.YES, Index.ANALYZED));
> w.addDocument(doc);
> if (i % 10000 == 0)
> {
> System.out.println(i);
> }
> }
> w.optimize();
> w.close();
> }
> }
>
> }
>
> import java.io.IOException;
>
> import org.apache.lucene.index.IndexReader;
> import org.apache.lucene.index.Term;
> import org.apache.lucene.search.IndexSearcher;
> import org.apache.lucene.search.MatchAllDocsQuery;
> import org.apache.lucene.search.Query;
> import org.apache.lucene.search.TermQuery;
> import org.apache.lucene.search.TopDocCollector;
>
> class TestThread implements Runnable
> {
> private IndexReader r;
> private int x;
> private Test callback;
> private boolean termSearches;
>
> public TestThread(IndexReader r, int x, Test callback,
> boolean termSearches)
> {
> this.r = r;
> this.x = x;
> this.callback = callback;
> this.termSearches = termSearches;
> }
>
> public void run() {
> long time = System.currentTimeMillis();
> System.out.println("Thread " + x + " start");
> IndexSearcher s = new IndexSearcher(r);
> Query q = null;
> if (termSearches)
> {
> q = new TermQuery(new Term("testfield",
> "testing"));
> }
> else
> {
> q = new MatchAllDocsQuery();
>
> }
> TopDocCollector col = new TopDocCollector(50);
> try {
> s.search(q, col);
> } catch (IOException e) {
> e.printStackTrace();
> }
> System.out.println("Time taken for " + x + " = "
> + (System.currentTimeMillis() - time));
> callback.callback();
> }
>
> }
>
> import java.io.IOException;
>
> import org.apache.lucene.index.CorruptIndexException;
> import org.apache.lucene.index.IndexReader;
>
>
> public class Test {
>
> private IndexReader r;
> private int noSearches = 0;
>
> public static void main(String[] args)
> {
> System.out.println("Running Single TermQuery Search");
> Test t = new Test(args[0]);
> try {
> t.runSearches(1, true);
> } catch (Exception e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> try {
> Thread.sleep(5000);
> } catch (InterruptedException e1) {
> // TODO Auto-generated catch block
> e1.printStackTrace();
> }
> System.out.println("Running Single MatchAllDocs
> Search");
> t = new Test(args[0]);
> try {
> t.runSearches(1, false);
> } catch (Exception e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> try {
> Thread.sleep(5000);
> } catch (InterruptedException e1) {
> // TODO Auto-generated catch block
> e1.printStackTrace();
> }
> System.out.println("Running two concurrent TermQuery
> Searches");
> t = new Test(args[0]);
> try {
> t.runSearches(2, true);
> } catch (Exception e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> try {
> Thread.sleep(5000);
> } catch (InterruptedException e1) {
> // TODO Auto-generated catch block
> e1.printStackTrace();
> }
> System.out.println("Running two concurrent MatchAllDocs
> Searches");
> t = new Test(args[0]);
> try {
> t.runSearches(2, false);
> } catch (Exception e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
>
> }
>
> public Test(String index)
> {
> try {
> r = IndexReader.open(index);
> } catch (CorruptIndexException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> } catch (IOException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> }
>
> public void runSearches(int no, boolean termSearches) throws
> Exception
> {
> noSearches = no;
> for (int i = 0; i < no; i++)
> {
> Thread t1 = new Thread(new TestThread(r, i,
> this, termSearches));
> t1.start();
> }
> }
>
> public void callback()
> {
> noSearches--;
> if (noSearches == 0)
> {
> try {
> r.close();
> } catch (IOException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> }
> }
>
> }
>
>
>
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