[ http://issues.apache.org/jira/browse/DERBY-1713?page=all ]
Ibrahim updated DERBY-1713:
---------------------------
Attachment: Test1.java
I simulated the problem exactly. I attached the code file [replace it with the
one in the previous attachment].
I found very strange behavior. It occurs in very specific situation.
The problem of not freeing the memory happens when calling a class which
contains db connection part [if you call the statements directly in the class,
the freeing process will work]. The SQL statements play a role also. The SQL
statement that causes the problem contains long WHERE clause that changes
dynamically, but this in its own will not cause a problem unless it comes after
another statement [SELECT count(*) ... ].
In summary, If I make any change in the SQL format or its place or .... , the
freeing process works perfectly except the case that I attached.
Please run the code and check it's memory behavior. I'm not sure if it will
work with you in the same way that it works with me. Also I'm not sure what is
the problem.
Please check if this is really a bug.
> Memory do not return to the system after Shuting down derby 10.2.1.0,
> following an out of memory event
> ------------------------------------------------------------------------------------------------------
>
> Key: DERBY-1713
> URL: http://issues.apache.org/jira/browse/DERBY-1713
> Project: Derby
> Issue Type: Bug
> Components: Performance
> Affects Versions: 10.2.1.0
> Environment: Windows XP SP2
> JRE 1.6 beta2
> Reporter: Ibrahim
> Priority: Critical
> Attachments: test.zip, Test1.java
>
>
> I face a problem when querying large tables. I run the below SQL and it stuck
> in this query and throws java heap exception OutOfMemory:
> SELECT count(*) FROM <table> WHERE .....
> N.B. I'm using a database of more than 90,000 records (40 MB). I set the
> maxHeap to 32 MB (all other settings have the default value, pageCache ...
> etc ).
> Then, I shutdown the database but the memory is not returned to the system
> (and remain 32 MB [max threshold]). I tried to increase the maxHeap to 128 MB
> in which it works and releases the memory, so I think the problem is when it
> reaches the maxHeap then it seems to not respond to anything such as closing
> the connection or shutting down the database. How can I get rid of this?
> (because i cannot increase the maxHeap as the database increases, I want to
> throw an exception and release the memory)
> I'm using this to shutdown the DB:
> try{DriverManager.getConnection("jdbc:derby:;shutdown=true");}
> catch(SQLException ex){System.err.println("SQLException: " +
> ex.getMessage());}
> I'm using a memory Profiler for monitoring the memory usage.
> Thanks in advanced.
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