PostgreSQL 18 with async read

1.txt

# ตรวจสอบ version
SELECT version();


PostgreSQL 18.0 (Debian 18.0-1.pgdg13+3) on aarch64-unknown-linux-gnu, compiled by gcc (Debian 14.2.0-19) 14.2.0, 64-bit

# ดูการ config
SELECT name, setting, context, short_desc
FROM pg_settings
WHERE name LIKE 'io_%'
ORDER BY name;

 io_combine_limit     | 32      | user       | Limit on the size of data reads and writes.
 io_max_combine_limit | 128     | postmaster | Server-wide limit that clamps io_combine_limit.
 io_max_concurrency   | 64      | postmaster | Max number of IOs that one process can execute simultaneously.
 io_method            | worker  | postmaster | Selects the method for executing asynchronous I/O.
 io_workers           | 6       | sighup     | Number of IO worker processes, for io_method=worker.

2.txt

# For worker method :: Background I/O Workers
ALTER SYSTEM SET io_method = 'worker';
ALTER SYSTEM SET io_workers = 4;

# For io_uring method (Linux only, requires liburing)
ALTER SYSTEM SET io_method = 'io_uring';

# For sync method (traditional behavior)
ALTER SYSTEM SET io_method = 'sync';

3.txt

CREATE EXTENSION IF NOT EXISTS pg_prewarm;

CREATE TABLE async_io_test (
    id SERIAL PRIMARY KEY,
    data TEXT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    random_num INTEGER,
    filler TEXT DEFAULT repeat('x', 100)
);

INSERT INTO async_io_test (data, random_num)
SELECT
    'Performance test data for async I/O - row ' || i,
    (random() * 1000000)::INTEGER
FROM generate_series(1, 500000) AS i;

CREATE INDEX idx_async_io_random ON async_io_test(random_num);
CREATE INDEX idx_async_io_created ON async_io_test(created_at);
CREATE INDEX idx_async_io_text ON async_io_test USING gin(to_tsvector('english', data));

4.txt

SELECT pg_stat_reset();
SELECT pg_prewarm('async_io_test'::regclass, 'buffer', 'main', NULL, NULL);

EXPLAIN (ANALYZE, BUFFERS, VERBOSE)
SELECT COUNT(*)
FROM async_io_test
WHERE data LIKE '%500000%';

EXPLAIN (ANALYZE, BUFFERS, VERBOSE)
SELECT id, data, random_num
FROM async_io_test
WHERE random_num BETWEEN 100000 AND 200000;