How many serials are in the "file that has a list of serials to delete"?

If it is a relatively small number, you could read them into a hash. Then you could read through the 15 billion line file line-by-line (thereby avoiding the need to keep the whole thing in memory at once); if the line's serial is in the "delete" hash then read the next line, otherwise print it to a new output file.

You'll need enough drive space to accommodate the new output file, of course, but it would accomplish the goal without using a db and with only minimal memory requirements, and it would still require only a single pass through the 15 billion line file.

In reply to Re: 15 billion row text file and row deletes - Best Practice? by bobf
in thread 15 billion row text file and row deletes - Best Practice? by awohld

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