Question

Suppose to have a ResultSet rs with n object.

This code:

while(rs.next()) {
   // do something on rs
}

is algoritmically equal to this code (i.e. both gave the same result):

for(i=1; i<=n; i++) {
   rs.absolute(i)
   // do something on rs
}

But are this equivalant on terms of throughouts? Is the first faster? Or, for a given i, rs.next() is just a wrapper for rs.absolute(i+1)?

Best regards
MC

Answer 1

rs.next demands a simpler kind of database cursor (FORWARD_ONLY) than rs.absolute so in most cases you will degrade performance/resource efficiency with rs.absolute. In certain cases, where there is no optimization for a FORWARD_ONLY cursor anyway, you may get the same performance.

Some drivers may allow absolute calls even with FORWARD_ONLY, validating that the requested record is the next one, but again others may throw an exception regardless.