Low Oracle Client version results in Bad SQL

Environment:

Production system is an online user 10K OLAP system (11g RAC two nodes), one day the user unit found that the scanner is slow.

View monitoring,Node1,io is high, heart rate is very high

Immediately proceed to analysis:

1. Original production client all link Node1, at this time found some clients do failover,node2 appear production client, very abnormal;

2. On Node1, kill the session client which causes the high Io, notify the user unit not to open temporarily;

3.Kill Node2 on the user, it is recommended to reopen the program, the exception disappears.

Analysis reason: The whole event, Node1 bad SQL caused by resource tension, some can not be Node1 response to the user, failover to Node2, when DRM works, scanning slower!

The Final Solution: The problem definitely out in the client, analogy normal client found that the client is 9i, then the field Engineer upgrade client to 11g problem resolution;

Root case: SQL for client program encapsulation, bad SQL on 9i client

Event Summary: 11g enterprise software is best to use 10g and above the client software to access!

Low Oracle Client version results in Bad SQL