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Posted to commits@phoenix.apache.org by ja...@apache.org on 2015/12/23 07:21:05 UTC
svn commit: r1721491 - in /phoenix/site: publish/faq.html
source/src/site/markdown/faq.md
Author: jamestaylor
Date: Wed Dec 23 06:21:05 2015
New Revision: 1721491
URL: http://svn.apache.org/viewvc?rev=1721491&view=rev
Log:
Update FAQ with pooling connection question
Modified:
phoenix/site/publish/faq.html
phoenix/site/source/src/site/markdown/faq.md
Modified: phoenix/site/publish/faq.html
URL: http://svn.apache.org/viewvc/phoenix/site/publish/faq.html?rev=1721491&r1=1721490&r2=1721491&view=diff
==============================================================================
--- phoenix/site/publish/faq.html (original)
+++ phoenix/site/publish/faq.html Wed Dec 23 06:21:05 2015
@@ -1,7 +1,7 @@
<!DOCTYPE html>
<!--
- Generated by Apache Maven Doxia at 2015-10-31
+ Generated by Apache Maven Doxia at 2015-12-22
Rendered using Reflow Maven Skin 1.1.0 (http://andriusvelykis.github.io/reflow-maven-skin)
-->
<html xml:lang="en" lang="en">
@@ -155,6 +155,7 @@
<li><a href="#How_do_I_connect_with_HBase_running_on_Hadoop-2">How do I connect with HBase running on Hadoop-2?</a></li>
<li><a href="#Can_phoenix_work_on_tables_with_arbitrary_timestamp_as_flexible_as_HBase_API">Can phoenix work on tables with arbitrary timestamp as flexible as HBase API?</a></li>
<li><a href="#Why_isnt_my_query_doing_a_RANGE_SCAN">Why isnât my query doing a RANGE SCAN?</a></li>
+ <li><a href="#Should_I_pool_Phoenix_JDBC_Connections">Should I pool Phoenix JDBC Connections?</a></li>
</ul>
<div class="section">
<div class="section">
@@ -354,6 +355,12 @@ conn.commit();
<p>FULL SCAN means that all rows of the table will be scanned over (potentially with a filter applied if you have a WHERE clause)</p>
<p>SKIP SCAN means that either a subset or all rows in your table will be scanned over, however it will skip large groups of rows depending on the conditions in your filter. See <a class="externalLink" href="http://phoenix-hbase.blogspot.com/2013/05/demystifying-skip-scan-in-phoenix.html">this</a> blog for more detail. We donât do a SKIP SCAN if you have no filter on the leading primary key columns, but you can force a SKIP SCAN by using the /<i>+ SKIP_SCAN </i>/ hint. Under some conditions, namely when the cardinality of your leading primary key columns is low, it will be more efficient than a FULL SCAN.</p>
</div>
+ <div class="section">
+ <h3 id="Should_I_pool_Phoenix_JDBC_Connections">Should I pool Phoenix JDBC Connections?</h3>
+ <p>No, it is not necessary to pool Phoenix JDBC Connections.</p>
+ <p>Phoenixâs Connection objects are different from most other JDBC Connections due to the underlying HBase connection. The Phoenix Connection object is designed to be a thin object that is inexpensive to create. If Phoenix Connections are reused, it is possible that the underlying HBase connection is not always left in a healthy state by the previous user. It is better to create new Phoenix Connections to ensure that you avoid any potential issues.</p>
+ <p>Implementing pooling for Phoenix could be done simply by creating a delegate Connection that instantiates a new Phoenix connection when retrieved from the pool and then closes the connection when returning it to the pool (see <a class="externalLink" href="https://issues.apache.org/jira/browse/PHOENIX-2388">PHOENIX-2388</a>).</p>
+ </div>
</div>
</div>
</div>
Modified: phoenix/site/source/src/site/markdown/faq.md
URL: http://svn.apache.org/viewvc/phoenix/site/source/src/site/markdown/faq.md?rev=1721491&r1=1721490&r2=1721491&view=diff
==============================================================================
--- phoenix/site/source/src/site/markdown/faq.md (original)
+++ phoenix/site/source/src/site/markdown/faq.md Wed Dec 23 06:21:05 2015
@@ -11,6 +11,7 @@
* [How do I connect with HBase running on Hadoop-2?](#How_do_I_connect_with_HBase_running_on_Hadoop-2)
* [Can phoenix work on tables with arbitrary timestamp as flexible as HBase API?](#Can_phoenix_work_on_tables_with_arbitrary_timestamp_as_flexible_as_HBase_API)
* [Why isn't my query doing a RANGE SCAN?](#Why_isnt_my_query_doing_a_RANGE_SCAN)
+* [Should I pool Phoenix JDBC Connections?](#Should_I_pool_Phoenix_JDBC_Connections)
### I want to get started. Is there a Phoenix _Hello World_?
@@ -277,3 +278,10 @@ FULL SCAN means that all rows of the tab
SKIP SCAN means that either a subset or all rows in your table will be scanned over, however it will skip large groups of rows depending on the conditions in your filter. See [this](http://phoenix-hbase.blogspot.com/2013/05/demystifying-skip-scan-in-phoenix.html) blog for more detail. We don't do a SKIP SCAN if you have no filter on the leading primary key columns, but you can force a SKIP SCAN by using the /*+ SKIP_SCAN */ hint. Under some conditions, namely when the cardinality of your leading primary key columns is low, it will be more efficient than a FULL SCAN.
+### Should I pool Phoenix JDBC Connections?
+
+No, it is not necessary to pool Phoenix JDBC Connections.
+
+Phoenix's Connection objects are different from most other JDBC Connections due to the underlying HBase connection. The Phoenix Connection object is designed to be a thin object that is inexpensive to create. If Phoenix Connections are reused, it is possible that the underlying HBase connection is not always left in a healthy state by the previous user. It is better to create new Phoenix Connections to ensure that you avoid any potential issues.
+
+Implementing pooling for Phoenix could be done simply by creating a delegate Connection that instantiates a new Phoenix connection when retrieved from the pool and then closes the connection when returning it to the pool (see [PHOENIX-2388](https://issues.apache.org/jira/browse/PHOENIX-2388)).