We also use SolrJ, and have a dynamically created Core capability - where we
don't know in advance what the Cores will be that we require.
We almost always do a complete index build, and if there's a previous instance
of that index, it needs to be available during a complete index build, so we
have two cores per index, and switch them as required at the end of an indexing
run.
Here's a summary of how we do it (we're in an early prototype / implementation
right now - this isn't production quality code - as you can tell from our
voluminous javadocs on the methods...)
1) Identify if the core exists, and if not, create it:
/**
* This method instantiates two SolrServer objects, solr and indexCore. It
requires that
* indexName be set before calling.
*/
private void initSolrServer() throws IOException
{
String baseUrl = "http://localhost:8983/solr/";;
solr = new CommonsHttpSolrServer(baseUrl);
String indexCoreName = indexName + SolrConstants.SUFFIX_INDEX; // SUFIX_INDEX =
"_INDEX"
String indexCoreUrl = baseUrl + indexCoreName;
// Here we create two cores for the indexName, if they don't already
exist - the live core used
// for searching and a second core used for indexing. After indexing,
the two will be switched so the
// just-indexed core will become the live core. The way that core
swapping works, the live core will always
// be named [indexName] and the indexing core will always be named
[indexname]_INDEX, but the
// dataDir of each core will alternate between [indexName]_1 and [indexName]_2.
createCoreIfNeeded(indexName, indexName + "_1", solr);
createCoreIfNeeded(indexCoreName, indexName + "_2", solr);
indexCore = new CommonsHttpSolrServer(indexCoreUrl);
}
/**
* Create a core if it does not already exists. Returns true if a new core
was created, false otherwise.
*/
private boolean createCoreIfNeeded(String coreName, String dataDir,
SolrServer server) throws IOException
{
boolean coreExists = true;
try
{
// SolrJ provides no direct method to check if a core exists, but
getStatus will
// return an empty list for any core that doesn't.
CoreAdminResponse statusResponse =
CoreAdminRequest.getStatus(coreName, server);
coreExists = statusResponse.getCoreStatus(coreName).size() > 0;
if(!coreExists)
{
// Create the core
LOG.info("Creating Solr core: " + coreName);
CoreAdminRequest.Create create = new CoreAdminRequest.Create();
create.setCoreName(coreName);
create.setInstanceDir(".");
create.setDataDir(dataDir);
create.process(server);
}
}
catch (SolrServerException e)
{
e.printStackTrace();
}
return !coreExists;
}
2) Do the index, clearing it first if it's a complete rebuild:
[snip]
if (fullIndex)
{
try
{
indexCore.deleteByQuery("*:*");
}
catch (SolrServerException e)
{
e.printStackTrace(); //To change body of catch statement use
File | Settings | File Templates.
}
}
[snip]
various logic, then (we submit batches of 100 :
[snip]
List<SolrInputDocument> docList = b.getSolrInputDocumentList();
UpdateResponse rsp;
try
{
rsp = indexCore.add(docList);
rsp = indexCore.commit();
}
catch (IOException e)
{
LOG.warn("Error commiting documents", e);
}
catch (SolrServerException e)
{
LOG.warn("Error commiting documents", e);
}
[snip]
3) optimize, then swap cores:
private void optimizeCore()
{
try
{
indexCore.optimize();
}
catch(SolrServerException e)
{
LOG.warn("Error while optimizing core", e);
}
catch(IOException e)
{
LOG.warn("Error while optimizing core", e);
}
}
private void swapCores()
{
String liveCore = indexName;
String indexCore = indexName + SolrConstants.SUFFIX_INDEX; // SUFFIX_INDEX =
"_INDEX"
LOG.info("Swapping Solr cores: " + indexCore + ", " + liveCore);
CoreAdminRequest request = new CoreAdminRequest();
request.setAction(CoreAdminAction.SWAP);
request.setCoreName(indexCore);
request.setOtherCoreName(liveCore);
try
{
request.process(solr);
}
catch (SolrServerException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
}
And that's about it.
You could adjust the above so there's only one core per index that you want -
if you don't do complete reindexes, and don't need the index to always be
searchable.
Hope that helps...
Bob Sandiford | Lead Software Engineer | SirsiDynix
P: 800.288.8020 X6943 | bob.sandif...@sirsidynix.com
www.sirsidynix.com
-----Original Message-----
From: Nizan Grauer [mailto:niz...@yahoo-inc.com]
Sent: Tuesday, November 09, 2010 3:36 AM
To: solr-user@lucene.apache.org
Subject: Dynamic creating of cores in solr
Hi,
I'm not sure this is the right mail to write to, hopefully you can help
or direct me to the right person
I'm using solr - one master with 17 slaves in the server and using
solrj as the java client
Currently there's only one core in all of them (master and slaves) -
only the cpaCore.
I thought about using multi-cores solr, but I have some problems with
that.
I don't know in advance which cores I'd need -
When my java program runs, I call for documents to be index to a
certain url, which contains the core name, and I might create a url
based on core that is not yet created. For example:
Calling to index - http://localhost:8080/cpaCore - existing core,
everything as usual
Calling to index - http://localhost:8080/newCore - server realizes
there's no core "newCore", creates it and indexes to it. After that -
also creates the new core in the slaves
Calling to index - http://localhost:8080/newCore - existing core,
everything as usual
What I'd like to have on the server side to do is realize by itself if
the cores exists or not, and if not - create it
One other restriction - I can't change anything in the client side -
calling to the server can only make the calls it's doing now - for
index and search, and cannot make calls for cores creation via the
CoreAdminHandler. All I can do is something in the server itself
What can I do to get it done? Write some RequestHandler?
REquestProcessor? Any other option?
Thanks, nizan
