Title: Re: [HACKERS] Merge algorithms for large numbers of "tapes"
Yes – all of the current best practice external sorts use two passes. A first to produce the runs, which results in “S” number of “files”, then a single merge pass across the runs. At most 1 pass across the S runs is required to implement the merge.
- Luke
On 3/7/06 8:03 PM, "Tom Lane" <[EMAIL PROTECTED]> wrote:
"Luke Lonergan" <[EMAIL PROTECTED]> writes:
> Two passes is the state-of-the-practice on external disk sorts.
There is no such thing as a fixed number of passes regardless of
available memory and size of the data.
regards, tom lane
