Em qui., 19 de ago. de 2021 às 07:50, Zhihong Yu <z...@yugabyte.com> escreveu:
> > > On Thu, Aug 19, 2021 at 2:52 AM Alexander Pyhalov < > a.pyha...@postgrespro.ru> wrote: > >> Hi. >> >> The attached patches allow pushing down >> current_timestamp/localtimestamp/current_time/localtime and now() to >> remote PostgreSQL server as locally computed parameters. >> The idea is based on oracle_fdw behavior. >> >> Examples. >> >> \d test >> Foreign table "public.test" >> Column | Type | Collation | Nullable | Default | >> FDW options >> >> --------+--------------------------+-----------+----------+---------+------------------- >> i | integer | | | | >> (column_name 'i') >> t | timestamp with time zone | | | | >> (column_name 't') >> Server: loopback >> FDW options: (schema_name 'data', table_name 'test') >> >> Prior the patch: >> >> explain verbose select * from test where t=current_timestamp; >> QUERY PLAN >> --------------------------------------------------------------------- >> Foreign Scan on public.test (cost=100.00..188.12 rows=11 width=12) >> Output: i, t >> Filter: (test.t = CURRENT_TIMESTAMP) >> Remote SQL: SELECT i, t FROM data.test >> >> explain verbose update test set t=current_timestamp where t<now(); >> QUERY PLAN >> >> ---------------------------------------------------------------------------- >> Update on public.test (cost=100.00..154.47 rows=0 width=0) >> Remote SQL: UPDATE data.test SET t = $2 WHERE ctid = $1 >> -> Foreign Scan on public.test (cost=100.00..154.47 rows=414 >> width=50) >> Output: CURRENT_TIMESTAMP, ctid, test.* >> Filter: (test.t < now()) >> Remote SQL: SELECT i, t, ctid FROM data.test FOR UPDATE >> >> >> After patch: >> explain verbose select * from test where t=current_timestamp; >> QUERY PLAN >> >> ------------------------------------------------------------------------------------- >> Foreign Scan on public.test (cost=100.00..144.35 rows=11 width=12) >> Output: i, t >> Remote SQL: SELECT i, t FROM data.test WHERE ((t = $1::timestamp with >> time zone)) >> >> explain verbose update test set t=current_timestamp where t<now(); >> QUERY PLAN >> >> ---------------------------------------------------------------------------------------------------------------------- >> Update on public.test (cost=100.00..137.93 rows=0 width=0) >> -> Foreign Update on public.test (cost=100.00..137.93 rows=414 >> width=50) >> Remote SQL: UPDATE data.test SET t = $1::timestamp with time >> zone WHERE ((t < $1::timestamp with time zone)) >> >> -- >> Best regards, >> Alexander Pyhalov, >> Postgres Professional > > Hi, > For 0001 patch: > > + if ((s->op != SVFOP_CURRENT_TIMESTAMP) && > + (s->op != SVFOP_CURRENT_TIMESTAMP_N) && > + (s->op != SVFOP_CURRENT_TIME) && > ... > > The above check appears more than once. If extracted into a helper method, > it would help reduce duplicate and make the code more readable. > Perhaps in a MACRO? regards, Ranier Vilela
