Hash Indexes

GaussDB(DWS) does not support hash indexes. DSC will replace these indexes with normal indexes based on GaussDB features.

1. Inline hash index

   Input

   CREATE TABLE `public`.`test_create_table03` (
   	`DEMAND_ID` INT(11) NOT NULL AUTO_INCREMENT,
   	`DEMAND_NAME` CHAR(100) NOT NULL,
   	`THEME` VARCHAR(200) NULL DEFAULT NULL,
   	`SEND_ID` INT(11) NULL DEFAULT NULL,
   	`SEND_NAME` CHAR(20) NULL DEFAULT NULL,
   	`SEND_TIME` DATETIME NULL DEFAULT NULL,
   	`DEMAND_CONTENT` TEXT NOT NULL,
   	PRIMARY KEY(`DEMAND_ID`),
       INDEX CON_INDEX(DEMAND_CONTENT(100)) USING HASH ,
       INDEX SEND_INFO_INDEX USING HASH (SEND_ID,SEND_NAME(10),SEND_TIME)
   );

   Output

   CREATE TABLE "public"."test_create_table03"
   (
     "demand_id" SERIAL NOT NULL,
     "demand_name" CHAR(100) NOT NULL,
     "theme" VARCHAR(200) DEFAULT NULL,
     "send_id" INTEGER(11) DEFAULT NULL,
     "send_name" CHAR(20) DEFAULT NULL,
     "send_time" TIMESTAMP WITHOUT TIME ZONE DEFAULT NULL,
     "demand_content" TEXT NOT NULL,
     PRIMARY KEY ("demand_id")
   )
     WITH ( ORIENTATION = ROW, COMPRESSION = NO )
     NOCOMPRESS
     DISTRIBUTE BY HASH ("demand_id");
   CREATE INDEX "con_index" ON "public"."test_create_table03" ("demand_content");
   CREATE INDEX "send_info_index" ON "public"."test_create_table03" ("send_id","send_name","send_time");

2. Hash index created by ALTER TABLE

   Input

   CREATE TABLE IF NOT EXISTS `public`.`runoob_alter_test`(
       `dataType1` int NOT NULL AUTO_INCREMENT,
       `dataType2` FLOAT(10,2),
       PRIMARY KEY(`dataType1`)
   )ENGINE=InnoDB DEFAULT CHARSET=utf8;
   
   ALTER TABLE runoob_alter_test ADD KEY alterTable_addKey_indexType(dataType1) USING HASH;

   Output

   CREATE TABLE "public"."runoob_alter_test"
   (
     "datatype1" SERIAL NOT NULL,
     "datatype2" FLOAT(10),
     PRIMARY KEY ("datatype1")
   )
     WITH ( ORIENTATION = ROW, COMPRESSION = NO )
     NOCOMPRESS
     DISTRIBUTE BY HASH ("datatype1");
   
   CREATE INDEX "altertable_addkey_indextype" ON "public"."runoob_alter_test" ("datatype1");

3. Hash index created by CREATE INDEX

   Input

   CREATE TABLE `public`.`test_index_table06` (
   	`ID` INT(11) NOT NULL AUTO_INCREMENT,
   	`FNAME` VARCHAR(30) NOT NULL,
   	`INAME` VARCHAR(30) NOT NULL,
   	PRIMARY KEY (`ID`)
   );
   CREATE INDEX FNAME_INDEX ON TEST_INDEX_TABLE06(FNAME(10)) USING HASH;
   CREATE INDEX NAME_01 ON TEST_INDEX_TABLE06(FNAME(10),INAME(10)) USING HASH;

   Output

   CREATE TABLE "public"."test_index_table06"
   (
     "id" SERIAL NOT NULL,
     "fname" VARCHAR(30) NOT NULL,
     "iname" VARCHAR(30) NOT NULL,
     PRIMARY KEY ("id")
   )
     WITH ( ORIENTATION = ROW, COMPRESSION = NO )
     NOCOMPRESS
     DISTRIBUTE BY HASH ("id");
   CREATE INDEX "fname_index" ON "public"."test_index_table06" ("fname");
   CREATE INDEX "name_01" ON "public"."test_index_table06" ("fname","iname");