PolarDB-X支持使用全局二级索引，本文将介绍如何使用SHOW GLOBAL INDEX命令查看已创建或创建中的全局二级索引。
语法
SHOW GLOBAL {INDEX | INDEXES} [FROM [schema_name.]tbl_name]
schema_name和tbl_name是可选的，用于过滤表名或查看其它数据库上表的信息。
show global index; # 查询当前数据库上所有表的全局二级索引信息 show global index from xxx_tb; # 查询当前数据库上 xxx_tb 的全局二级索引信息 show global index from xxx_db.xxx_tb; # 查询 xxx_db 上 xxx_tb 的全局二级索引信息（跨库查询）
示例
mysql> show global index; +---------------------+----------------------+------------+-------------------------------+----------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------+------------------+---------------------+--------------------+------------------+---------------------+--------------------+----------+ | SCHEMA | TABLE | NON_UNIQUE | KEY_NAME | INDEX_NAMES | COVERING_NAMES | INDEX_TYPE | DB_PARTITION_KEY | DB_PARTITION_POLICY | DB_PARTITION_COUNT | TB_PARTITION_KEY | TB_PARTITION_POLICY | TB_PARTITION_COUNT | STATUS | +---------------------+----------------------+------------+-------------------------------+----------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------+------------------+---------------------+--------------------+------------------+---------------------+--------------------+----------+ | XXXX_DRDS_LOCAL_APP | full_gsi_ddl_renamed | 1 | g_i_c_ddl_c_blob_long_renamed | c_blob_long | id, c_bit_1, c_bit_8, c_bit_16, c_bit_32, c_bit_64, c_tinyint_1, c_tinyint_1_un, c_tinyint_4, c_tinyint_4_un, c_tinyint_8, c_tinyint_8_un, c_smallint_16, c_smallint_16_un, c_mediumint_1, c_mediumint_24, c_mediumint_24_un, c_int_1, c_int_32, c_int_32_un, c_bigint_1, c_bigint_64, c_bigint_64_un, c_decimal, c_decimal_pr, c_float, c_float_pr, c_float_un, c_double, c_double_pr, c_double_un, c_date, c_datetime, c_datetime_3, c_datetime_6, c_timestamp_1, c_timestamp_3, c_time, c_time_1, c_time_3, c_time_6, c_year, c_year_4, c_char, c_varchar, c_binary, c_varbinary, c_blob_tiny, c_blob_medium, c_text_tiny, c_text, c_text_medium, c_text_long, c_enum, c_set, c_json, c_point, c_linestring, c_polygon, c_multipoint, c_multilinestring, c_multipolygon, c_geometrycollection, c_geometory | NULL | c_blob_long | HASH | 4 | c_blob_long | HASH | 3 | PUBLIC | | XXXX_DRDS_LOCAL_APP | full_gsi_ddl_renamed | 1 | g_i_c_ddl_c_mediumint_1 | c_mediumint_1 | id, c_bit_1, c_bit_8, c_bit_16, c_bit_32, c_bit_64, c_tinyint_1, c_tinyint_1_un, c_tinyint_4, c_tinyint_4_un, c_tinyint_8, c_tinyint_8_un, c_smallint_16, c_smallint_16_un, c_mediumint_24, c_mediumint_24_un, c_int_1, c_int_32, c_int_32_un, c_bigint_1, c_bigint_64, c_bigint_64_un, c_decimal, c_decimal_pr, c_float, c_float_pr, c_float_un, c_double, c_double_pr, c_double_un, c_date, c_datetime, c_datetime_3, c_datetime_6, c_timestamp_1, c_timestamp_3, c_time, c_time_1, c_time_3, c_time_6, c_year, c_year_4, c_char, c_varchar, c_binary, c_varbinary, c_blob_tiny, c_blob_medium, c_blob_long, c_text_tiny, c_text, c_text_medium, c_text_long, c_enum, c_set, c_json, c_point, c_linestring, c_polygon, c_multipoint, c_multilinestring, c_multipolygon, c_geometrycollection, c_geometory, c_smallint_1, c_timestamp_6 | NULL | c_mediumint_1 | HASH | 4 | c_mediumint_1 | HASH | 3 | PUBLIC | | XXXX_DRDS_LOCAL_APP | full_gsi_ddl_renamed | 1 | g_i_c_ddl_c_smallint_16_un | c_smallint_16_un, c_time_1 | id, c_bit_1, c_bit_8, c_bit_16, c_bit_32, c_bit_64, c_tinyint_1, c_tinyint_1_un, c_tinyint_4, c_tinyint_4_un, c_tinyint_8, c_tinyint_8_un, c_smallint_16, c_mediumint_1, c_mediumint_24, c_mediumint_24_un, c_int_1, c_int_32, c_int_32_un, c_bigint_1, c_bigint_64, c_bigint_64_un, c_decimal, c_decimal_pr, c_float, c_float_pr, c_float_un, c_double, c_double_pr, c_double_un, c_date, c_datetime, c_datetime_3, c_datetime_6, c_timestamp_1, c_timestamp_3, c_time, c_time_3, c_time_6, c_year, c_year_4, c_char, c_varchar, c_binary, c_varbinary, c_blob_tiny, c_blob_medium, c_blob_long, c_text_tiny, c_text, c_text_medium, c_text_long, c_enum, c_set, c_json, c_point, c_linestring, c_polygon, c_multipoint, c_multilinestring, c_multipolygon, c_geometrycollection, c_geometory | NULL | c_smallint_16_un | HASH | 4 | c_smallint_16_un | HASH | 3 | PUBLIC | | XXXX_DRDS_LOCAL_APP | t_order | 0 | g_i_seller | seller_id | id, order_id | HASH | seller_id | HASH | 4 | seller_id | HASH | 2 | CREATING | +---------------------+----------------------+------------+-------------------------------+----------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+------------+------------------+---------------------+--------------------+------------------+---------------------+--------------------+----------+ 4 rows in set (0.01 sec)
表 1. 列名说明
| 列名 | 说明 |
| SCHEMA | 库名 |
| TABLE | 表名 |
| NON_UNIQUE | 是否为唯一约束全局二级索引，取值范围如下：
|
| KEY_NAME | 索引名 |
| INDEX_NAMES | 索引列 |
| COVERING_NAMES | 覆盖列 |
| INDEX_TYPE | 索引类型，取值范围如下：
|
| DB_PARTITION_KEY | 分库拆分键 |
| DB_PARTITION_POLICY | 分库拆分函数 |
| DB_PARTITION_COUNT | 分库数量 |
| TB_PARTITION_KEY | 分表拆分键 |
| TB_PARTITION_POLICY | 分表拆分函数 |
| TB_PARTITION_COUNT | 分表数 |
| STATUS | 索引的当前状态，取值范围如下：
|
