Is there an issue with Central Africa Time (CAT) PostgreSQL TIMESTAMPTZ conversion? - postgresql

Question

One of our PostgreSQL 11.4 deployments in Congo uses the CAT timezone (Africa/Kigali +02) and one of our function chokes when trying to convert human-input timestamps to actual TIMESTAMPTZ data.
For example:
SELECT '2019-10-17 00:00:00 CAT'::TIMESTAMPTZ;
ERROR: invalid input syntax for type timestamp with time zone: "2019-10-17 00:00:00 CAT"
LINE 2: SELECT '2019-10-17 00:00:00 CAT'::TIMESTAMPTZ
^
SQL state: 22007
Character: 9
But when I try with CEST (Central European, also +02) it works.
SELECT '2019-10-17 00:00:00 CEST'::TIMESTAMPTZ;
"2019-10-17 00:00:00+02"
Incidentally, converting from epoch to CAT also works
select to_timestamp(1571263200);
"2019-10-17 00:00:00+02"
Version:
"PostgreSQL 11.4 (Ubuntu 11.4-1.pgdg18.04+1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0, 64-bit" on Ubuntu 18.04.2 LTS

Answer 1

For whatever reason, 'CAT' is not valid for input by default, presumably someone felt it was ambiguous or something. You could append the line
CAT 7200 # Central Africa Time
to the file "$SHAREDIR/timezonesets/Default" to make this work.
Or you could create a file "$SHAREDIR/timezonesets/Africa" with the contents:
#INCLUDE Default
#OVERRIDE
CAT 7200 # Central Africa Time
And then set the parameter timezone_abbreviations to 'Africa'.
I am not horologist, you might want to research why CAT is missing before blindly adding it. Also, if you go either of the above routes, you should document it clearly someplace. You will need to repeat the steps you took when you upgrade PostgreSQL, or restore or move your database.
Or, you could preprocess your user input to replace 'CAT' with 'Africa/Kigali'.
Incidentally, converting from epoch to CAT also works
select to_timestamp(1571263200);
"2019-10-17 00:00:00+02"
'CAT' does not appear in your example. So it is not clear what this is an example of.