JDBC + MySQL : "Operation Not Allowed After ResultSet Closed"

Question

I have a very short piece of code. I use one connection to the database. I execute a query, get back a lot of rows, then iterate through the result set and for each row I get some information and then perform an insert into a different table.
The problem is that the big result set I am iterating through keeps closing sometime during the first iteration. Why? I am using three different statements:
1) Statement 1 is for the main query I want to iterate through
2) Statement 2 is for a quick lookup I perform (on a different table) for each item in the iteration.
3) Statement 3 is for the Insert statement which I perform for each item in the iteration. Again, I insert into a different table and I use "executeUpdate"
Given the I have three different statements and I am working with three different tables, why does my main result set that I am iterating through keep closing on me?
Here is the error I am getting:
java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.ResultSet.checkClosed(ResultSet.java:3603)
at com.mysql.jdbc.ResultSet.next(ResultSet.java:2468)
at com.mysql.jdbc.UpdatableResultSet.next(UpdatableResultSet.java:565)
Thanks for your help.

Answer 1

I have a very short piece of code. I use one
connection to the database. I execute a query, get
back a lot of rows, then iterate through the result
set and for each row I get some information and then
perform an insert into a different table.Sounds like a classic case of making Java do what the database was made to do.
I'd bet you can do this in a single INSERT with a SELECT in the database in one network roundtrip. The "quick lookup" might be a JOIN or a sub-SELECT. When you do a query, bring N rows back to the middle tier, then do an INSERT for each row that you retrieve it means (N+1) network roundtrips if you don't batch your INSERTs. I'd have a SQL expert give your code a look.
The problem is that the big result set I am iterating
through keeps closing sometime during the first
iteration. Why? I am using three different
statements:
1) Statement 1 is for the main query I want to
iterate through
2) Statement 2 is for a quick lookup I perform (on a
different table) for each item in the iteration.
3) Statement 3 is for the Insert statement which I
perform for each item in the iteration. Again, I
insert into a different table and I use
"executeUpdate"
Given the I have three different statements and I am
working with three different tables, why does my main
result set that I am iterating through keep closing
on me?Maybe your ResultSet or Statement goes out of scope. Do the Statements share a Connection?
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