[Solr Wiki] Update of "SolrPerformanceProblems" by ShawnHeisey

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The "SolrPerformanceProblems" page has been changed by ShawnHeisey:
https://wiki.apache.org/solr/SolrPerformanceProblems?action=diff&rev1=79&rev2=80

Comment:
Add heap size issues to the list of possible problems causing slow commits.  link update for the ignore commit/optimize update processor.

   * Large autowarmCount values on Solr caches.
   * Extremely frequent commits.
   * Not enough OS memory for disk caching, discussed above.
+  * Heap size issues.  Problems from the heap being too small are more likely that problems from the heap being too large.
  
  If you have large autowarmCount values on your Solr caches, it can take a very long time to do that cache warming.  The filterCache is particularly slow to warm.  The solution is to reduce the autowarmCount, reduce the complexity of your queries, or both.
  
  If you commit very frequently, you may send a new commit before the previous commit is finished.  If you have cache warming enabled as just discussed, this is more of a problem.  If you have a high maxWarmingSearchers in your solrconfig.xml, you can end up with a lot of new searchers warming at the same time, which is very I/O intensive, so the problem compounds itself.
  
- If you are having problems with slow commit times when '''NOT''' opening a new searcher, then this is probably due to a general performance problem, like extreme GC pauses or not enough OS memory for disk caching.  Both of these issues are discussed earlier on this page.
+ If you are having problems with slow commit times when '''NOT''' opening a new searcher, then this is probably due to general performance problems/  Some of these issues are discussed earlier on this page.
  
  == Slow Indexing ==
  
  There are *MANY* reasons for slow indexing.  Most of the time it will not be Solr that is slow.  The biggest reason for slow indexing is the speed of information retrieval from the source system.
  
- Other possible problems that cause slow indexing include committing after every update request, sending one document at a time in each update request instead of batching them, and only using one thread/connection to index.  These are problems that are external to Solr. Possible workaround is using the [[https://cwiki.apache.org/confluence/display/solr/Shards+and+Indexing+Data+in+SolrCloud|IgnoreCommitOptimizeUpdateProcessorFactory]] to ignore all commits from client and instead setup autoCommit.
+ Other possible problems that cause slow indexing include committing after every update request, sending one document at a time in each update request instead of batching them, and only using one thread/connection to index.  These are problems that are external to Solr. Possible workaround is using the [[https://lucene.apache.org/solr/guide/shards-and-indexing-data-in-solrcloud.html#ignoring-commits-from-client-applications-in-solrcloud|IgnoreCommitOptimizeUpdateProcessorFactory]] to ignore all commits from client and instead setup autoCommit.
  
  == Further help ==