Re: Since '2001-09-09 01:46:40'::timestamp microseconds are lost when extracting epoch

Here is a new patch series version.

I have created a new internal function for converting integers to
numeric, to make the implementation a bit more elegant and compact.

I have also created a new date_part(..., date) in C, and added more test
coverage for that.

Other than some of the semantic issues mentioned in the previous
message, this version looks pretty good to me in principle.

I have done some performance tests to assess the impact of changing from
float to numeric. I did tests like this:

create table t1 (a int, b timestamp with time zone);
insert into t1 select generate_series(1, 10000000), current_timestamp +
random() * interval '1000 days';

select extract(dow from b) from t1 \g /dev/null
select extract(epoch from b) from t1 \g /dev/null

There appears to be about a 20% increase in run time for these tests.
These are obviously extreme tests, so I think that would be okay. More
tests and testing ideas are welcome.

--
Peter Eisentraut http://www.2ndQuadrant.com/
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