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Posted to dev@velocity.apache.org by dl...@apache.org on 2003/11/01 01:22:22 UTC
cvs commit: jakarta-velocity/xdocs developer-guide.xml
dlr 2003/10/31 16:22:22
Modified: xdocs developer-guide.xml
Log:
* xdocs/developer-guide.xml
Stressed the importance of the parser.pool.size property. Under
extremely high concurrency, too low a value for this property can
result in degraded performance and GC thrash.
Revision Changes Path
1.74 +12 -9 jakarta-velocity/xdocs/developer-guide.xml
Index: developer-guide.xml
===================================================================
RCS file: /home/cvs/jakarta-velocity/xdocs/developer-guide.xml,v
retrieving revision 1.73
retrieving revision 1.74
diff -u -u -r1.73 -r1.74
--- developer-guide.xml 26 Oct 2003 13:14:54 -0000 1.73
+++ developer-guide.xml 1 Nov 2003 00:22:21 -0000 1.74
@@ -2104,16 +2104,19 @@
<p>
<code>parser.pool.size = 20</code><br/>
-This property sets the number of parsers that Velocity will
+This property sets the number of parser instances that Velocity will
create at startup and keep in a pool. The default of 20 parsers
-should be more than enough for most uses. In the event
-that Velocity does run out of parsers, it will indicate
-so in the log, and
-dynamically create them as needed. Note that they will not
-be added to the pool. This is a slow operation compared to
-the normal parser pooling, but this is considered an
-exceptional condition. If you see a log message, please
-increment this property.
+should be more than enough for most uses. In the event that Velocity
+does run out of parsers, it will indicate so in the log, and
+dynamically create overflow instances as needed. Note that these
+extra parsers will not be added to the pool, and will be discarded
+after use. This will result in very slow operation compared to the
+normal usage of pooled parsers, but this is considered an exceptional
+condition. A web application using Velocity as its view engine might
+exhibit this behavior under extremely high concurrency (such as when
+getting Slashdotted). If you see a corresponding message referencing
+the <code>parser.pool.size</code> property in your log files, please
+increment this property immediately to avoid performance degradation.
</p>
<p>
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