Hibernate with oracle 9 and 10

Question

Hi,
We're are developing application using hibernate and oracle database. Our application currently using hibernate 3.1.2 and oracle jdbc 9. Because we are using 10.2 version of database, we decided to migrate to jdbc 10.2.0.4 driver version. And there the problem appears: one of queries, which joins 2 tables (one about 550K rows, and second about 130K rows), using hibernate and jdbc 9 runs in seconds, but using hibernate and jdbc 10 runs in 10 minutes. But the same query executed with pure jdbc 10 (without hibernate) executes normally (as on jdbc 9). During execution cpu usage is 100%, it doesn't happen on jdbc 9. I traced sql session and the execution plans for both jdbc version are the same. Fetch_size in jdbc is the same in both cases. In tkprof out files i discovered, that fetch time for this query is extremely long on jdbc 10, no other differences could be found. Has anyone experienced such behavior of hibernate and jdbc drivers with different versions? Is there any chance to migrate from jdbc 9 to jdbc 10?
Regards
Olek

Answer 1

Hello
I can't explain the longer fetch time
I find it strange that the oracle shadow processes is busy, that would indicate an issue on the database side
That is why I asked to do more investigation into the trace
If you set those events, you will get more info in your trace file, you will get the oracle wait events that occurred
This will give more information about why the oracle shadow process was at 100%
Here is what I am looking for, I set the events and then ran a select on our database , here is the output from tkprof
See at the bottom where it has the 'Elapsed times include waiting on following events:', that is what I'd like to see
If you already have this detailed info, could you post it for both the 9 and 10 test?
select count(*)
from
mytab where mycol like '%xx%'
call count cpu elapsed disk query current rows
Parse 1 0.02 0.02 0 0 1 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 2 9.45 56.14 237740 237762 0 1
total 4 9.47 56.17 237740 237762 1 1
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 299
Rows Row Source Operation
1 SORT AGGREGATE (cr=237762 pr=237740 pw=0 time=56147059 us)
3 TABLE ACCESS FULL mytab (cr=237762 pr=237740 pw=0 time=53139375 us)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
SQL*Net message to client 2 0.00 0.00
db file scattered read 14914 0.19 51.74
SQL*Net message from client 2 4.94 5.10
If you can't create a logon trigger, could you change your java to run these alter sessions before running the sql?
alter session set sql_trace=true;
alter session set events '10046 trace name context forever, level 12';
alter session set events '10053 trace name context forever, level 1';
Thanks