Today to work with the user could not reflect the login system, with its working tried can log in and find that reflect the problem users try to work number, can not login, check the log in the query, the simple statement, select epmno the from user where empno='F123', not query for 5 minutes as a result, change the job number only need 10 milliseconds can check out the results,

CodePudding user response:

Study the building 10053, look at this statement waiting for what,

CodePudding user response:

Not strange, if guess, at least, there may be a kind of reason:
1, empno data distribution may not be balanced, although look from the field name should not be, but happen there will be a garbage data;
Histogram of the form 2, uniform data, but some problems;
3, the likelihood is cardinality feedback functions, leading to the execution of the plan,

Still have a problem with no problem on the first time the execution of the plan under the contrast