Peter Geoghegan <pg@heroku.com> writes:
> On Mon, Apr 21, 2014 at 5:50 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> ARC *was* the predecessor algorithm. See commit 5d5087363.
> I believe that the main impetus for replacing ARC with clock sweep
> came from patent issues, though.
That was one issue, but performance gains were a large part of it too,
and the main reason why we picked clock sweep rather than something else.
Did you read the commit message I pointed to?
(See also 4e8af8d27.)
regards, tom lane