数据仓库服务 GaussDB(DWS)-ALGORITHM

时间：2025-02-12 15:05:07

ALGORITHM

MySQL扩展了对ALTER TABLE … ALGORITHM=INSTANT的支持：用户可以在表的任何位置即时添加列、即时删除列、添加列时评估行大小限制。

GaussDB (DWS)不支持此属性，并在迁移过程中被DSC删除。

输入示例

     
          ALTER TABLE runoob_alter_test ALGORITHM=DEFAULT;ALTER TABLE runoob_alter_test ALGORITHM=INPLACE;ALTER TABLE runoob_alter_test ALGORITHM=COPY;ALTER TABLE runoob_alter_test ADD COLUMN COL_18 VARCHAR(64)  DEFAULT '00', ALGORITHM=INSTANT;ALTER TABLE runoob_alter_test MODIFY COLUMN dataType7 BIGINT, ALGORITHM=COPY;ALTER TABLE `runoob_alter_test` ALGORITHM=DEFAULT, ALGORITHM=INPLACE, ALGORITHM=COPY;ALTER TABLE `runoob_alter_test` ADD COLUMN dataType11 INT, ALGORITHM=DEFAULT, ALGORITHM=INPLACE, ALGORITHM=COPY;ALTER TABLE runoob_alter_test CHANGE COLUMN dataType11 dataType12 SMALLINT ,ALGORITHM=INPLACE, ALGORITHM=COPY;ALTER TABLE runoob_alter_test ALGORITHM=INPLACE, ALGORITHM=COPY, DROP COLUMN dataType12;

输出示例

     
          ALTER TABLE  "public"."runoob_alter_test"ADD  COLUMN "col_18" VARCHAR(256) DEFAULT '00';ALTER TABLE  "public"."runoob_alter_test" MODIFY "datatype7" BIGINT NULL DEFAULT NULL;ALTER TABLE  "public"."runoob_alter_test"ADD  COLUMN "datatype11" INTEGER;ALTER TABLE  "public"."runoob_alter_test" CHANGE COLUMN "datatype11" "datatype12" SMALLINT NULL DEFAULT NULL;ALTER TABLE  "public"."runoob_alter_test" DROP COLUMN "datatype12" RESTRICT;DROP TABLE IF EXISTS "public"."runoob_alter_test";