We are running into a unique issue.. We recently migrated a database from 11.2 to 12.2 for testing.
When we compared the performance, 12.2 performance was 3x-4x slow compared to 11g.
When we were peeling the layers to troubleshoot, we discovered:
- A query which runs in 3 seconds at the database directly (in 12.2) takes between 11-14 seconds when it is run through a client like pl/sql developer.
- To eliminate the variables, we ran sqlplus from another host (which is in same network), and the execution time was still over 13 seconds.
- sqlplus on the DB server (using tns/sqlnet) produces the result in about 3 seconds as well
- Sysadmin says, Network throughput between the servers have no issue, he was able to scp a 500MB file in less than 2 seconds.
Here is the output from SQL trace.. the output from running the query from the DB server and through the client produce identical output, except the elapsed time..
<snip>
583 rows selected.
Elapsed: 00:00:02.51 vs Elapsed: 00:00:11.44
Execution Plan
Plan hash value: 2598178018
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1220 | 56120 | 1244 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | 47 | | |
|* 2 | TABLE ACCESS BY INDEX ROWID BATCHED| AES_FLD_TYPE | 1 | 47 | 2 (0)| 00:00:01 |
|* 3 | INDEX RANGE SCAN | AES_IDX_FTYPE_RTYPE | 1 | | 1 (0)| 00:00:01 |
|* 4 | TABLE ACCESS FULL | AES_REC_TYPE | 1220 | 56120 | 24 (0)| 00:00:01 |
------------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
2 - filter("AES_FLD_TYPE"."DELETED_DATE" IS NULL)
3 - access("AES_FLD_TYPE"."REC_TYPE_ID"=:B1 AND "AES_FLD_TYPE"."CLIENT_ID"=:B2)
4 - filter("AES_REC_TYPE"."DELETED_DATE" IS NULL AND "AES_REC_TYPE"."CLIENT_ID"=12313400144)
Statistics
66503 recursive calls
0 db block gets
71151 consistent gets
0 physical reads
0 redo size
382206 bytes sent via SQL*Net to client
248383 bytes received via SQL*Net from client
1168 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
583 rows processed
