PostgreSQL 9.6 Cast text datetime to timetamptz different results-CodePudding

Why may I have different results of casting text datetime to timestamptz on my Postgres server?

The first date casts to 03, but the second one casts to 04. Why?

I have Postgres 9.6, my config:

datestyle = 'iso, mdy';
timezone = 'W-SU';
lc_time = 'ru_RU.UTF-8'

CodePudding user response：

There must be a daylight savings time change between these two dates, so that in your session time zone (determined by the current setting of the timezone parameter) a different UTC offset is used.

W-SU is an alias for Europe/Moscow, and Moscow changed from daylight savings time in the night from Oct 25 (Saturday) to Oct 26 (Sunday).