core isolation

[Dominique Bejean <do...@eolya.fr>]

Hi,

In Solr 3.x the parameter "abortOnConfigurationError=false" allows cores 
continue to work even if an other core fails due to a configuration error.

This parameter doesn't exist anymore in Solr 4.0 but afetr some tests, 
it looks like cores are isolated from each other. By isolated, I mean if 
a core fails due to a configuration error or an error like 
ClassNotFoundException, the other cores continue to work.

In an other hand I think there are some errors that will make all cores 
hang :

* OutOfMemoryError
* OutOfMemoryError : PermGen space
* Too many open files
* ...


I am using Tomcat 6, can somebody confirm this "isolation" in Solr 4.0 ? 
Which errors do not impact other cores and which errors impact other cores ?

Regards

Dominique

Re: core isolation

[Chris Hostetter <ho...@fucit.org>]

: looks like cores are isolated from each other. By isolated, I mean if a core
: fails due to a configuration error or an error like ClassNotFoundException,
: the other cores continue to work.

For the most part this is true ... SolrCore's are islated form eachother 
as much as possible -- but some things like static variables in Lucene 
code or plugins loaded from the "sharedLib" in solr.xml will be common 
between all cores -- the most common example of this being Lucene's 
BooleanQuery.getMaxClauseCount()

: In an other hand I think there are some errors that will make all cores hang :
: 
: * OutOfMemoryError
: * OutOfMemoryError : PermGen space
: * Too many open files

corret ... if  a severe problem happens at the JVM process level, then all 
SolrCores are affected.

You can run discrete JVM processes if you wish to avoid this, but then 
there is added resource overhead.


-Hoss