Automatic partitioning by day - PostgreSQL

R. Pereira picture R. Pereira · Apr 12, 2019 · Viewed 14.4k times · Source

I would like to do a daily partitions. I know with oracle is something like this.

CREATE TABLE "PUBLIC"."TEST"     
(   
"ID" NUMBER(38,0) NOT NULL ENABLE, 
"SOME_FIELD" VARCHAR2(20 BYTE) NOT NULL ENABLE,     
"ANOTHER_FIELD" VARCHAR2(36 BYTE) NOT NULL ENABLE,    
TABLESPACE "PUBLIC"."TEST_DATA" 
PARTITION BY RANGE ("TEST_DATE") INTERVAL (NUMTODSINTERVAL(1,'DAY'))  
(PARTITION "TEST_P1"  
VALUES LESS THAN (TIMESTAMP' 2019-01-01 00:00:00')   TABLESPACE "TEST_DATA" );

What about PostgreSQL?

NEW EDIT: SAMPLE SCRIPT:

The script which will maintain first 15 days data in one table say "p1" and remaining days data in another partition.

1- Creating automatic partion depends on the date range of insert command

2- In script i have also mentioned that how we can add index on the required column's.

3- Data from date range from 1st to 14th will be added in partition "p1" and remaining will be added in partition "p2".

Sample Script :

    CREATE TABLE measurement (
        city_id         int not null,
        logdate         date not null,
        peaktemp        int,
        unitsales       int
    );

    CREATE OR REPLACE FUNCTION new_partition_creator() RETURNS trigger AS
  $BODY$
    DECLARE
      partition_date TEXT;
      partition TEXT;
      partition_day int;
      startdate date;
      enddate date;
    BEGIN
      partition_day := to_char(NEW.logdate,'DD');
      partition_date := to_char(NEW.logdate,'YYYY_MM');

         IF partition_day < 15 THEN
      partition := TG_RELNAME || '_' || partition_date || '_p1';
      startdate := to_char(NEW.logdate,'YYYY-MM-01');
      enddate := date_trunc('MONTH', NEW.logdate) + INTERVAL '1 MONTH - 1 day';
      ELSE 
      partition := TG_RELNAME || '_' || partition_date || '_p2';
      startdate := to_char(NEW.logdate,'YYYY-MM-15');
      enddate := date_trunc('MONTH', NEW.logdate) + INTERVAL '1 MONTH - 1 day';
      END IF;

      IF NOT EXISTS(SELECT relname FROM pg_class WHERE relname=partition) THEN
        RAISE NOTICE 'A partition has been created %',partition;
        EXECUTE 'CREATE TABLE ' || partition || ' ( CHECK ( logdate >= DATE ''' || startdate || '''  AND logdate <=  DATE ''' ||  enddate || ''' )) INHERITS (' || TG_RELNAME || ');';
        EXECUTE 'CREATE INDEX ' || partition || '_logdate ON '  || partition || '(logdate)';
        EXECUTE 'ALTER TABLE ' || partition || ' add primary key(city_id);';       
        END IF;
        EXECUTE 'INSERT INTO ' || partition || ' SELECT(' || TG_RELNAME || ' ' || quote_literal(NEW) || ').* RETURNING city_id;';
      RETURN NULL;
    END;
  $BODY$
LANGUAGE plpgsql VOLATILE
COST 100; 


    CREATE TRIGGER testing_partition_insert_trigger BEFORE INSERT ON measurement FOR EACH ROW EXECUTE PROCEDURE new_partition_creator();


    postgres=# insert into measurement values(1,'2017-10-11',10,10);
    NOTICE:  A partition has been created measurement_2017_10_p1
    INSERT 0 0

Answer

Amol Tarte picture Amol Tarte · Apr 12, 2019

You can use extension pg_partman for automatic partition creation. https://github.com/pgpartman/pg_partman

or you can even use scheduler pg_agent where you will execute a procedure every day at say 18:00:00 to create next days partition.