I have a NON-Cloud Solr and I am trying to use the swap functionality to
push an updated core into production without downtime.
Here are the steps I am executing
1. Solr is up and running with a single core (name = 'livecore')
2. I create a new core with the latest version of my documents (name =
'newcore')
3. I swap the cores -> coreContainer.swap("newcore", "livecore")
4. I try to unload "newcore" (that points to the old one) and remove all
the related dirs -> coreContainer.unload("newcore", true, true, true)
The first three operations are OK. But when I try to execute the last one
the Solr log starts printing the following messages forever
61424 INFO (pool-1-thread-1) [ x:newcore] o.a.s.c.SolrCore Core newcore is
not yet closed, waiting 100 ms before checking again.
I have opened an issue on this problem (
https://issues.apache.org/jira/browse/SOLR-8757) but I have not received
any answer yet.
In the meantime I have found the following workaround: I try to manually
close all the core references before unloading it. Here is the code:
SolrCore core = coreContainer.create("newcore", coreProps)
coreContainer.swap("newcore", "livecore")
// the old livecore is now newcore, so unload it and remove all the
related dirsSolrCore oldCore = coreContainer.getCore("newCore")while
(oldCore.getOpenCount > 1) {
oldCore.close()
}
coreContainer.unload("newcore", true, true, true)
This seemed to work but there is some race conditions and from time to time
I get a ConcurrentModificationException and then an abnormal CPU
consumption.
I filed a separate issue on this
https://issues.apache.org/jira/browse/SOLR-9208 but this is not considered
an issue by the Solr committers. The suggestion is to move and discuss it
here in the mailing list.
If this is not an issue, what are the steps to swap to cores and unload one
of them?
Thanks a lot,
Fabrizio
