Data Batch Inserts

title: Batch INSERT Statements for Bulk Data impact: MEDIUM impactDescription: 10-50x faster bulk inserts tags: batch, insert, bulk, performance, copy

Batch INSERT Statements for Bulk Data

Individual INSERT statements have high overhead. Batch multiple rows in single statements or use COPY.

Incorrect (individual inserts):

-- Each insert is a separate transaction and round trip
insert into events (user_id, action) values (1, 'click');
insert into events (user_id, action) values (1, 'view');
insert into events (user_id, action) values (2, 'click');
-- ... 1000 more individual inserts

-- 1000 inserts = 1000 round trips = slow

Correct (batch insert):

-- Multiple rows in single statement
insert into events (user_id, action) values
  (1, 'click'),
  (1, 'view'),
  (2, 'click'),
  -- ... up to ~1000 rows per batch
  (999, 'view');

-- One round trip for 1000 rows

For large imports, use COPY:

-- COPY is fastest for bulk loading
copy events (user_id, action, created_at)
from '/path/to/data.csv'
with (format csv, header true);

-- Or from stdin in application
copy events (user_id, action) from stdin with (format csv);
1,click
1,view
2,click
\.

Reference: COPY