db-derby-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Stanley Bradbury <Stan.Bradb...@gmail.com>
Subject Re: Momory leak in JDBC driver?
Date Mon, 05 Sep 2005 16:57:08 GMT
Hi All -

I want to point out that the DRDA standard (Network Server and the 
client) as well as the JDBC standard needs to be referenced to 
dertermine what is 'proper' behavior.  The Network layer (DRDA) has it's 
own optimizations and, in my experience,  is the source of many 'memory 
leaks' because objects that are buffered in this layer are not freed for 
garbage collection unless the object are closed.  

Hope this helps.

Wei Jiang wrote:

>java.sql javadoc says:
>
>Note: A Statement object is automatically closed when it is garbage collected.
>When a Statement object is closed, its current ResultSet object, if one exists,
>is also closed.
>
>I do not close ResultSet. But I do close Statement. Is it possible that
>when derby's Statement closed, the ResultSet is not?
>
>I did forget to close one statement. After a while, Oracle's coneection 
>automatically closed, so I found the problem and closed that statement after
>use. Here, I am not trying to compare oracle with derby, but trying to say
>that PROBABALY I close all Statement.
>
>
>  
>
>
>From: Dyre.Tjeldvoll@Sun.COM
>
>Wei Jiang <_weijiang_@yahoo.com> writes:
>
>  
>
>>Hi,
>>
>>I tried Derby using the default JDBC driver and found memory leak. When I use
>>Hsql or Oracle, I do not have such leak. So probably it is the JDBC driver.
>>    
>>
>
>Two things:
>
>1) Are you closing your ResultSets? If just let the ResultSet objects
>   pass out of scope without closing them, they will be "leaked". That
>   is, the driver keeps a linked list of them so they won't be
>   gc'ed. I have experienced this myself, but I don't know if there is
>   a JIRA issue for it
>
>2) Are you using blobs/clobs? From what I have seen on this (and the
>   derby-dev) list, it seems that blobs/clobs cannot be streamed, and this
>   can result in "Out of Memory" errors when using large blobs/clobs.
>
>
>	
>		
>______________________________________________________
>Click here to donate to the Hurricane Katrina relief effort.
>http://store.yahoo.com/redcross-donate3/
>
>  
>



Mime
View raw message