Hi guys,
I'm having a problem with my servlet that runs on Tomcat and uses
Connector/J 5.1.7 to connect to MySQL. I'm quite certain that I don't keep
any database objects laying around in my servlet, yet the JVM fills up. I
used jmap to do a histogram of the running servlet, and it's filled with
database-related objects that I thought should have been garbage-collected
long ago:
| class |
bytes | count |
+----------------------------------------------------------------------+----------+--------+
| com.mysql.jdbc.Field |
55555488 | 385802 |
| com.mysql.jdbc.ByteArrayRow |
10269536 | 641846 |
| com.mysql.jdbc.ResultSetImpl |
5166128 | 29353 |
| com.mysql.jdbc.StatementImpl |
3972528 | 27587 |
| com.mysql.jdbc.Field[] |
1841728 | 18926 |
| com.mysql.jdbc.PreparedStatement |
349856 | 1508 |
| com.mysql.jdbc.RowDataStatic |
141600 | 5900 |
| com.mysql.jdbc.PreparedStatement$ParseInfo |
60320 | 1508 |
| com.mysql.jdbc.Buffer |
40080 | 1670 |
| com.mysql.jdbc.DatabaseMetaData |
36312 | 1513 |
| com.mysql.jdbc.ConnectionPropertiesImpl$BooleanConnectionProperty |
34240 | 535 |
| com.mysql.jdbc.ConnectionPropertiesImpl$StringConnectionProperty |
8960 | 140 |
| com.mysql.jdbc.ConnectionPropertiesImpl$IntegerConnectionProperty |
8000 | 125 |
| com.mysql.jdbc.ConnectionImpl |
5360 | 5 |
| com.mysql.jdbc.VersionedStringProperty |
2112 | 66 |
| com.mysql.jdbc.MysqlIO |
1120 | 5 |
| com.mysql.jdbc.ConnectionPropertiesImpl$MemorySizeConnectionProperty |
1080 | 15 |
| com.mysql.jdbc.ConnectionPropertiesImpl$LongConnectionProperty
| 360 | 5 |
| com.mysql.jdbc.util.ReadAheadInputStream
| 160 | 5 |
| com.mysql.jdbc.StandardSocketFactory
| 120 | 5 |
| com.mysql.jdbc.log.StandardLogger
| 80 | 5 |
| com.mysql.jdbc.SingleByteCharsetConverter
| 48 | 3 |
| com.mysql.jdbc.Driver
| 16 | 2 |
| com.mysql.jdbc.log.NullLogger
| 8 | 1 |
I have no idea why 385802 fields should be laying around or 29353 resultsets
and 27587 statements. Do you have any suggestions as to what's going on, or
how I can debug this?
Cheers
Nik
