sql - PostgreSQL表的实现历史

Question

我想实现 PostgreSQL 表的变化历史。该表按以下方式定义:

CREATE TABLE "ps_counters"
(
    "psid" integer NOT NULL,
    "counter" bigint[] NOT NULL
);

我希望历史表看起来像:

CREATE TABLE "ps_counters_history"
(
    "timestamp" timestamp NOT NULL,
    "psid" integer NOT NULL,
    "counter" bigint[] NOT NULL
);

我需要一个触发器和一个存储过程，在 ps_couneters 中的每次更改(插入或更新)时插入到 ps_counters_history 中，但除了防止 ps_counters_history 变得太大我想每个月对 ps_counters_history 表进行分区。

Answer 1

我设法实现了它。

CREATE TABLE "ps_counters_history"
(
  "id" serial PRIMARY KEY,
  "timestamp" timestamp NOT NULL DEFAULT clock_timestamp(),
  "psid" integer NOT NULL,
  "counter" bigint[] NOT NULL
);

CREATE OR REPLACE FUNCTION ps_counters_history_trigger()
  RETURNS trigger AS
$BODY$
  DECLARE
    table_name text;
  BEGIN
    table_name := 'ps_counters_history_' || to_char(CURRENT_DATE, 'yyyy_mm');
    IF NOT EXISTS (SELECT 1 FROM pg_class WHERE relname = table_name)
    THEN
      EXECUTE 'CREATE TABLE IF NOT EXISTS ' || table_name ||
              ' () INHERITS (ps_counters_history);';
    END IF;
    EXECUTE 'INSERT INTO ' || table_name ||
            '(psid, counter) VALUES ($1.psid, $1.counter);' USING NEW;
    RETURN NEW;
  END
$BODY$
  LANGUAGE plpgsql;

CREATE TRIGGER ps_counters_history_trigger
AFTER INSERT OR UPDATE ON ps_counters FOR EACH ROW
EXECUTE PROCEDURE ps_counters_history_trigger();