-----Original Message-----
From: Jonathan Rochkind [mailto:rochk...@jhu.edu]
Sent: Wednesday, November 10, 2010 3:26 PM
To: solr-user@lucene.apache.org
Subject: Re: Dynamic creating of cores in solr
You could use the actual built-in Solr replication feature to
accomplish
that same function -- complete re-index to a 'master', and then when
finished, trigger replication to the 'slave', with the 'slave' being
the
live index that actually serves your applications.
I am curious if there was any reason you chose to roll your own
solution
using JSolr and dynamic creation of cores, instead of simply using
the
replication feature. Were there any downsides of using the
replication
feature for this purpose that you amerliorated through your solution?
Jonathan
Bob Sandiford wrote:
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
