Hi,
> I am using 1.0.72 version of H2 and the database is in-memory.
In any case I suggest to use a newer version.
>> As a performance test, I loaded about 125K rows in the tables. The
>> memory went up 1 GB. After that I ran a TRUNCATE TABLE command on
>> each of the tables. I wanted to see if the memory footprint of the
>> server process to come down. However it still remained the same.
Java doesn't shrink the heap size as far as I know. I don't think this
can be solved in H2.
>> added about half the old data. The memory increased by another
>> expected 500MB close to 1.5GB from the intial memory footprint.
That's strange, it would mean the original data is still referenced in
memory. I can't reproduce this, see my test case below.
Regards,
Thomas
Class.forName("org.h2.Driver");
Connection conn;
Statement stat;
conn = DriverManager.getConnection("jdbc:h2:mem:test", "sa", "sa");
stat = conn.createStatement();
for(int j=0; j<10; j++) {
stat.execute("create table test"+j+"(name varchar) as select 'hello '
|| x from system_range(1, 200000)");
Runtime rt = Runtime.getRuntime();
for(int i=0; i<10; i++) rt.gc();
System.out.println("free: " + ((rt.maxMemory()-rt.freeMemory())/1024/1024));
stat.execute("truncate table test" + j);
for(int i=0; i<10; i++) rt.gc();
System.out.println("after drop: " +
((rt.maxMemory()-rt.freeMemory())/1024/1024));
}
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