PolarDB-for-PostgreSQL

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drop table tttest;
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create table tttest (
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	price_id	int4,
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	price_val	int4,
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	price_on	abstime,
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	price_off	abstime
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);
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create unique index tttest_idx on tttest (price_id,price_off);
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alter table tttest add column q1 text;
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alter table tttest add column q2 int;
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alter table tttest drop column q1;
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create trigger timetravel
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	before insert or delete or update on tttest
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	for each row
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	execute procedure
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	timetravel (price_on, price_off);
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insert into tttest values (1, 1, null, null);
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insert into tttest(price_id, price_val) values (2, 2);
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insert into tttest(price_id, price_val,price_off) values (3, 3, 'infinity');
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insert into tttest(price_id, price_val,price_off) values (4, 4,
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	abstime('now'::timestamp - '100 days'::interval));
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insert into tttest(price_id, price_val,price_on) values (3, 3, 'infinity'); -- duplicate key
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select * from tttest;
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delete from tttest where price_id = 2;
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select * from tttest;
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-- what do we see ?
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-- get current prices
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select * from tttest where price_off = 'infinity';
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-- change price for price_id == 3
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update tttest set price_val = 30 where price_id = 3;
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select * from tttest;
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-- now we want to change price_id from 3 to 5 in ALL tuples
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-- but this gets us not what we need
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update tttest set price_id = 5 where price_id = 3;
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select * from tttest;
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-- restore data as before last update:
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select set_timetravel('tttest', 0);	-- turn TT OFF!
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select get_timetravel('tttest');	-- check status
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delete from tttest where price_id = 5;
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update tttest set price_off = 'infinity' where price_val = 30;
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select * from tttest;
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-- and try change price_id now!
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update tttest set price_id = 5 where price_id = 3;
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select * from tttest;
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-- isn't it what we need ?
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select set_timetravel('tttest', 1);	-- turn TT ON!
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select get_timetravel('tttest');	-- check status
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-- we want to correct some date
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update tttest set price_on = 'Jan-01-1990 00:00:01' where price_id = 5 and
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	price_off <> 'infinity';
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-- but this doesn't work
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-- try in this way
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select set_timetravel('tttest', 0);	-- turn TT OFF!
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select get_timetravel('tttest');	-- check status
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update tttest set price_on = '01-Jan-1990 00:00:01' where price_id = 5 and
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	price_off <> 'infinity';
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select * from tttest;
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-- isn't it what we need ?
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-- get price for price_id == 5 as it was '10-Jan-1990'
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select * from tttest where price_id = 5 and
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	price_on <= '10-Jan-1990' and price_off > '10-Jan-1990';
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