Sounds like an ideal job for Tie::File::AsHash ?

Anyway, you really want to avoid reading DUMP_B millions of times, once for every line in DUMP_A. It should be possible to read in both files once, and create a hash for each, keyed by the ID field, then iterate through the hash for DUMP_A and look up the corresponding entry in the hash for DUMP_B - this is the reason I suggested the above module (haven't actually tried it, shame on me) - you should be able to treat each dump file like a hash, and split on whatever character you want.

In reply to Re: Reg: Performance by mjscott2702
in thread Reg: Performance by sivaraman

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