Re^3: Speed up file write taking weeks

You wrote: "The input files contain 65 million and 72 million records. The output file has 1.7 trillion records." And then, "We guess that the 1.7 trillion records will generate around 100 million unique records".

If the final result is the generation of these 100 million "unique records" (whatever that means), what is your plan for doing that from this humongous flat file of 1.7 trillion records? A factor of millions is a lot!

It is plausible to have an SQL DB with 65 + 72 million records. If those 2 tables combine to produce a smaller table (less than the sum of the input rows) of 100 million, I suspect there is a much more efficient algorithm to do that. However, I just don't know enough about what you are doing! My gosh what will you do with this 1.7 trillion record file after you generate it? How will you arrive at the 100 million unique records?

Comment on Re^3: Speed up file write taking weeks

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Re^4: Speed up file write taking weeks by Sanjay (Sexton) on Nov 22, 2019 at 16:00 UTC
Summarise based on another field	[reply]
Re^5: Speed up file write taking weeks by Marshall (Canon) on Nov 30, 2019 at 01:46 UTC
It is plausible to have 2 tables, one with 65 million records and one with 72 million records and, generate a resulting table of 100 million records without having to build a multi-trillion line intermediate table.	[reply]