Bharath Vissapragada has posted comments on this change.

Change subject: IMPALA-2347: Reuse metastore client connections in Catalog
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Patch Set 2:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/3381/2//COMMIT_MSG
Commit Message:

Line 13: this patch increases the default intial metastore pool size to 10 from
> typo: initial. Why did you decide to increase this? I have seen connection 
- Like I mentioned in the other comment, earlier every call to a getClient() 
will create a new MetastoreClient. This patch can ease the behavior a little by 
re-using the connections as the release() call now puts them in the pool and 
further getClients() will reuse these connections. 

- Regarding the increase in  initial pool size, I did so as I feel it is very 
less after looking at how often we use getClient() calls (CatalogOp calls).


http://gerrit.cloudera.org:8080/#/c/3381/2/fe/src/main/java/com/cloudera/impala/catalog/MetaStoreClientPool.java
File fe/src/main/java/com/cloudera/impala/catalog/MetaStoreClientPool.java:

Line 76:     public void release() {
> Some time I saw connection to be in the hundreds which means this may not b
It could be due to two things, 

1) Like you mentioned, we may not be calling release() properly which is a 
leak, (please raise a jira if you see code where release() isn't being called.)

2) We don't set a limit on the max no. of connections.  If you see the behavior 
prior to this patch, we just create a new MetaStoreClient() for every 
getClient() call. This under heavy load can appear as a lot of connections.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I517c0e1efef2584cd8d34017b33574f2ad69bd52
Gerrit-PatchSet: 2
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Bharath Vissapragada <[email protected]>
Gerrit-Reviewer: Bharath Vissapragada <[email protected]>
Gerrit-Reviewer: Dimitris Tsirogiannis <[email protected]>
Gerrit-Reviewer: Huaisi Xu <[email protected]>
Gerrit-HasComments: Yes

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