Meta Table
Index
The Meta Tables are tables that present the schema information of Machbase. The table names begin with “M$”.
These tables hold the table name, column information, and index information, and reflect the creation, modification and deletion information resulting from the DDL statement. The Meta Tables can not be added, deleted, or changed by the user.
User Objects
M$SYS_TABLES
Displays the table created by the user.
| Column Name | Description |
|---|---|
| NAME | Table name |
| TYPE | Table type - 0: Log - 1: Fixed - 3: Volatile - 4: Lookup - 5: Key Value - 6: Tag |
| DATABASE_ID | Database identifier |
| ID | Table identifier |
| USER ID | User of created table |
| COLCOUNT | Number of columns |
| FLAG | classification Table Type - 1 : Tag Data Table - 2 : Rollup Table - 4 : Tag Meta Table - 8 : Tag Stat Table |
M$SYS_TABLE_PROPERTY
Displays table property information applied to each table.
| Column Name | Description |
|---|---|
| ID | Table identifier |
| NAME | Property Name |
| VALUE | Property Value |
M$SYS_COLUMNS
Displays the column information of the user table displayed in M$SYS_TABLES.
| Column Name | Description |
|---|---|
| NAME | Column name |
| TYPE | Column type |
| DATABASE_ID | Database identifier |
| ID | Column identifier |
| LENGTH | Column length |
| TABLE_ID | Table identifier of column |
| FLAG | (Information for internal use of the server) |
| PART_PAGE_COUNT | Pages per partition |
| PAGE_VALUE_COUNT | Number of data per page |
| MINMAX_CACHE_SIZE | Size of MIN-MAX cache |
| MAX_CACHE_PART_COUNT | Maximum number of partition caches |
M$SYS_INDEXES
Displays the index information generated by the user.
| Column Name | Description |
|---|---|
| NAME | Index name |
| TYPE | Index type |
| DATABASE_ID | Database identifier |
| ID | Index identifier |
| TABLE_ID | Table of index identifier |
| COLCOUNT | Number of columns of created index |
| PART_VALUE_COUNT | Number of data per partition of index table |
| BLOOM_FILTER | Availability of Bloom Filter |
| KEY_COMPRESS | Compression status of key values |
| MAX_LEVEL | Maximum level of index (LSM only) |
| PAGE_SIZE | Page size |
| MAX_KEYWORD_SIZE | Maximum keyword length (keyword only) |
| BITMAP_ENCODE | Bitmap encoding type (RANGE / EQUAL) |
M$SYS_INDEX_COLUMNS
Displays the column information of the user index shown in M$SYS_INDEXES.
| Column Name | Description |
|---|---|
| INDEX_ID | Index identifier |
| INDEX_TYPE | Index type |
| NAME | Column name |
| COL_ID | Column identifier |
| DATABASE_ID | Database identifier |
| TABLE_ID | Table identifier |
| TYPE | Data type of column |
M$SYS_TABLESPACES
Displays the table space information created by the user.
| Column Name | Description |
|---|---|
| NAME | Tablespace name |
| ID | Tablespace identifier |
| DISK_COUNT | Number of disks in tablespace |
M$SYS_TABLESPACE_DISKS
Maintains the disk information used by the tablespace.
| Column Name | Description |
|---|---|
| NAME | Disk name |
| ID | Disk identifier |
| TABLESPACE_ID | Disk tablespace identifier |
| PATH | Disk path |
| IO_THREAD_COUNT | Number of IO threads allocated to this disk |
| VIRTUAL_DISK_COUNT | Number of Virtual Disk units assigned to this disk |
M$SYS_USERS
Maintain user information registered in Machbase.
| Column Name | Description |
|---|---|
| USER_ID | User identifier |
| NAME | User name |
M$RETENTION
Displays the RETENTION POLICY information.
| Column Name | Description |
|---|---|
| USER_ID | User ID |
| POLICY_NAME | policy name |
| DURATION | retention period(sec) |
| INTERVAL | update cycle(sec) |
Others
M$TABLES
Display all meta tables beginning with M$.
| Column Name | Description |
|---|---|
| NAME | Meta table name |
| TYPE | Table type |
| DATABASE_ID | Database identifier |
| ID | Meta table identifier |
| USER ID | Table user (in this case, SYS) |
| COLCOUNT | Number of columns |
M$COLUMNS
Displays the column information of the meta table displayed in M$TABLES.
| Column Name | Description |
|---|---|
| NAME | Column name |
| TYPE | Column type |
| DATABASE_ID | Database identifier |
| ID | Column identifier |
| LENGTH | Column length |
| TABLE_ID | Column table identifier |
| FLAG | (Information for internal use of the server) |
| PART_PAGE_COUNT | Pages per partition |
| PAGE_VALUE_COUNT | Number of data per page |
| MINMAX_CACHE_SIZE | Size of MIN-MAX cache |
| MAX_CACHE_PART_COUNT | Maximum number of partition caches |