GBase 8a数据库集群,当前版本目前只支持一种hash索引,同时提供了元数据表 information_schema. statistics 查看索引情况。
gbase> select * from information_schema.statistics where table_schema='testdb'; 其中GLOBAL HASH是hash索引,GROUPED是行存列索引,其为一个数据结构,内部使用,不算标准索引类型。
样例
gbase> show create table t1;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
| t1 | CREATE TABLE "t1" (
"id" int(11) DEFAULT NULL,
"value" int(11) DEFAULT NULL
) ENGINE=EXPRESS DEFAULT CHARSET=utf8 TABLESPACE='sys_tablespace' |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (Elapsed: 00:00:00.00)
gbase> create index idx_id on testdb.t1(id) key_block_size=4096 using hash global;
Query OK, 0 rows affected (Elapsed: 00:00:01.62)
Records: 0 Duplicates: 0 Warnings: 0
gbase> show create table t1;
+-------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| t1 | CREATE TABLE "t1" (
"id" int(11) DEFAULT NULL,
"value" int(11) DEFAULT NULL,
KEY "idx_id" ("id") KEY_BLOCK_SIZE=4096 USING HASH GLOBAL
) ENGINE=EXPRESS DEFAULT CHARSET=utf8 TABLESPACE='sys_tablespace' |
+-------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (Elapsed: 00:00:00.00)
gbase> select * from information_schema.statistics where table_schema='testdb';
+---------------+--------------+------------+------------+--------------+------------+--------------+-------------+-----------+-------------+----------+--------+----------+-------------+---------+
| TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME | NON_UNIQUE | INDEX_SCHEMA | INDEX_NAME | SEQ_IN_INDEX | COLUMN_NAME | COLLATION | CARDINALITY | SUB_PART | PACKED | NULLABLE | INDEX_TYPE | COMMENT |
+---------------+--------------+------------+------------+--------------+------------+--------------+-------------+-----------+-------------+----------+--------+----------+-------------+---------+
| NULL | testdb | t1 | 1 | testdb | idx_id | 1 | id | NULL | NULL | NULL | NULL | YES | GLOBAL HASH | |
+---------------+--------------+------------+------------+--------------+------------+--------------+-------------+-----------+-------------+----------+--------+----------+-------------+---------+
1 row in set (Elapsed: 00:00:00.00)
gbase> select * from information_schema.statistics where table_schema='testdb'\G;
*************************** 1. row ***************************
TABLE_CATALOG: NULL
TABLE_SCHEMA: testdb
TABLE_NAME: t1
NON_UNIQUE: 1
INDEX_SCHEMA: testdb
INDEX_NAME: idx_id
SEQ_IN_INDEX: 1
COLUMN_NAME: id
COLLATION: NULL
CARDINALITY: NULL
SUB_PART: NULL
PACKED: NULL
NULLABLE: YES
INDEX_TYPE: GLOBAL HASH
COMMENT:
1 row in set (Elapsed: 00:00:00.00)
ERROR:
No query specified
其它元数据信息请参考