MySQL:Udfyld en tabel i en lagret procedure effektivt

Brug ikke loops, især på den skala i RDBMS.

Prøv hurtigt at fylde din tabel med 1m rækker med en forespørgsel

INSERT INTO `entity_versionable` (fk_entity, str1, str2, bool1, double1, date)
SELECT 1, 'a1', 100, 1, 500000, '2013-06-14 12:40:45'
  FROM
(
select a.N + b.N * 10 + c.N * 100 + d.N * 1000 + e.N * 10000 + f.N * 100000 + 1 N
from (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) a
      , (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) b
      , (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) c
      , (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) d
      , (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) e
      , (select 0 as N union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) f
) t

Det tog min boks (MacBook Pro 16GB RAM, 2,6Ghz Intel Core i7) ~8 sek at fuldføre

Query OK, 1000000 rows affected (7.63 sec)
Records: 1000000  Duplicates: 0  Warnings: 0

OPDATERING 1 Nu en version af en lagret procedure, der bruger en forberedt erklæring

DELIMITER $$
CREATE PROCEDURE `inputRowsNoRandom`(IN NumRows INT)
BEGIN
    DECLARE i INT DEFAULT 0;

    PREPARE stmt 
       FROM 'INSERT INTO `entity_versionable` (fk_entity, str1, str2, bool1, double1, date)
             VALUES(?, ?, ?, ?, ?, ?)';
    SET @v1 = 1, @v2 = 'a1', @v3 = 100, @v4 = 1, @v5 = 500000, @v6 = '2013-06-14 12:40:45';

    WHILE i < NumRows DO
        EXECUTE stmt USING @v1, @v2, @v3, @v4, @v5, @v6;
        SET i = i + 1;
    END WHILE;

    DEALLOCATE PREPARE stmt;
END$$
DELIMITER ;

Fuldført på ~3 min:

mysql> CALL inputRowsNoRandom(1000000);
Query OK, 0 rows affected (2 min 51.57 sec)

Føl forskellen 8 sek vs 3 min.

OPDATERING 2 For at fremskynde tingene kan vi eksplicit bruge transaktioner og forpligte indsættelser i batches. Så her kommer en forbedret version af SP.

DELIMITER $$
CREATE PROCEDURE inputRowsNoRandom1(IN NumRows BIGINT, IN BatchSize INT)
BEGIN
    DECLARE i INT DEFAULT 0;

    PREPARE stmt 
       FROM 'INSERT INTO `entity_versionable` (fk_entity, str1, str2, bool1, double1, date)
             VALUES(?, ?, ?, ?, ?, ?)';
    SET @v1 = 1, @v2 = 'a1', @v3 = 100, @v4 = 1, @v5 = 500000, @v6 = '2013-06-14 12:40:45';

    START TRANSACTION;
    WHILE i < NumRows DO
        EXECUTE stmt USING @v1, @v2, @v3, @v4, @v5, @v6;
        SET i = i + 1;
        IF i % BatchSize = 0 THEN 
            COMMIT;
            START TRANSACTION;
        END IF;
    END WHILE;
    COMMIT;
    DEALLOCATE PREPARE stmt;
END$$
DELIMITER ;

Resultater med forskellige batchstørrelser:

mysql> CALL inputRowsNoRandom1(1000000,1000);
Query OK, 0 rows affected (27.25 sec)

mysql> CALL inputRowsNoRandom1(1000000,10000);
Query OK, 0 rows affected (26.76 sec)

mysql> CALL inputRowsNoRandom1(1000000,100000);
Query OK, 0 rows affected (26.43 sec)

Du ser selv forskellen . Stadig> 3 gange værre end cross join.