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Created April 6, 2019 10:08
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Optimizing postgresql table for more than 100K inserts per second

Optimizing postgresql table for more than 100K inserts per second

  • Create UNLOGGED table. This reduces the amount of data written to persistent storage by up to 2x.
  • Set WITH (autovacuum_enabled=false) on the table. This saves CPU time and IO bandwidth on useless vacuuming of the table (since we never DELETE or UPDATE the table).
  • Insert rows with COPY FROM STDIN. This is the fastest possible approach to insert rows into table.
  • Minimize the number of indexes in the table, since they slow down inserts. Usually an index on time timestamp with time zone is enough.
  • Add synchronous_commit = off to postgresql.conf.
  • Use table inheritance for fast removal of old data:
CREATE TABLE parent ... ;
CREATE TABLE child_1() INHERITS (parent);
CREATE TABLE child_2() INHERITS (parent);

-- always INSERT rows into child_1.
-- SELECT from parent.

-- periodically run the follwing sql for rotating child_1 with child_2:
TRUNCATE TABLE child_2;
BEGIN;
ALTER TABLE child_1 RENAME TO child_tmp;
ALTER TABLE child_2 RENAME TO child_1;
ALTER TABLE child_tmp RENAME TO child_2;
COMMIT;

This is much faster comparing to

DELETE FROM parent WHERE time < now() - interval 'given period'

This also avoids table fragmentation, so SELECT queries work faster on the table.

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