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What are effective methods for retriving many number of rows from postgreSQL tables using perl DBI?
Depending on how many columns in your result set, and how complicated your query, 3,000,000 records shouldn't be that big of a deal. You really should show us your perl code, your SQL, and your database schema as you could be doing something strange that's eating your memory and we would never know it. For instance, if you load the entire result set into a perl array, that might not be the best thing for memory consumption. Another for instance, if you're doing a 5 table join on all columns but are only using a few columns from the result set, that too might not be the best thing.