MAJOR and MINOR|V4.3.1| docs|Distributed Database

MAJOR and MINOR

Last Updated：2024-06-28 05:30:31 Updated

Purpose

You can use this statement in the sys tenant to initiate a compaction in the storage layer. You can initiate a major compaction at the tenant or partition level. You can initiate a minor compaction at the tenant, zone, OBServer node, log stream, or partition level.

Syntax

ALTER SYSTEM merge_action;

merge_action:
      MAJOR FREEZE [tenant_list]
    | MAJOR FREEZE tenant_list TABLET_ID = tablet_id
    | MINOR FREEZE [tenant_list | TABLET_ID = tablet_id] [server_list] [zone_list] [LS [=] ls_id];
    | {SUSPEND | RESUME} MERGE [tenant_list]
    | CLEAR MERGE ERROR [tenant_list]

tenant_list:
    TENANT [=]  { all | all_user | all_meta } | tenant_name [, tenant_name ...]

server_list:
    SERVER [=] ('ip:port' [, 'ip:port'...])

zone_list:
    ZONE [=] ('zone_name' [, 'zone_name' ...]);

Parameters

Parameter	Description
MAJOR FREEZE	Initiates a major compaction. You can use `TENANT=all` or `TENANT=all_user` to initiate a major compaction for all user tenants. We recommend that you use `all_user`, because `all` will be deprecated in future versions. You can use `TENANT=all_meta` to initiate a major compaction for all meta tenants. You can also use `TENANT=tenant_name [, tenant_name ...]` to initiate a major compaction only for specified tenants.
MINOR FREEZE	Initiates a minor compaction.
{SUSPEND \| RESUME} MERGE	Suspends or resumes a major compaction. You can use `TENANT=all` or `TENANT=all_user` to suspend or resume a major compaction for all user tenants. We recommend that you use `all_user`, because `all` will be deprecated in future versions. You can use `TENANT=all_meta` to suspend or resume a major compaction for all meta tenants. You can also use `TENANT=tenant_name [, tenant_name ...]` to suspend or resume a major compaction only for specified tenants.
CLEAR MERGE ERROR	Removes major compaction error tags. You can use `TENANT=all` or `TENANT=all_user` to remove major compaction error tags for all user tenants. We recommend that you use `all_user`, because `all` will be deprecated in future versions. You can use `TENANT=all_meta` to remove major compaction error tags for all meta tenants. You can also use `TENANT=tenant_name [, tenant_name ...]` to remove major compaction error tags only for specified tenants.
MAJOR FREEZE TENANT [=] tenant_name TABLET_ID = tablet_id	Initiates a partition-level major compaction for a specified tablet ID. Note You can execute this statement only in the `sys` tenant.
tenant_name	The name of the tenant for which a major or minor compaction is to be initiated.
TABLET_ID	The ID of the partition for which a major or minor compaction is to be initiated.
SERVER	The OBServer node for which a minor compaction is to be initiated.
ZONE	The zone for which a minor compaction is to be initiated.
LS	The log stream for which a minor compaction is to be initiated.

Considerations

One partition corresponds to one tablet. When you initiate a partition-level major compaction, take note of the following considerations:

You cannot initiate a partition-level major compaction for a partition that is undergoing a tenant-level major compaction.
You cannot initiate a partition-level major compaction for a partition that is undergoing an adaptively scheduled major compaction.
You cannot initiate a partition-level major compaction for a partition if multiple replicas of the partition are inconsistent.
You cannot initiate a partition-level major compaction for a partition in the restoring or transfer state.
You cannot initiate a partition-level major compaction when the major compaction task is suspended.
A partition-level major compaction is essentially a major compaction on multiple replicas of a partition. It consumes CPU and disk I/O resources. Before you initiate a partition-level major compaction, check the resource usage of the tenant. After the partition-level major compaction is completed, the CPU and I/O usage will increase.

Examples

Major compaction in the storage layer

Initiate a major compaction in the sys tenant for the tenant itself.
```
obclient> ALTER SYSTEM MAJOR FREEZE;
Query OK, 0 rows affected
```

Initiate a major compaction in the sys tenant for all user tenants.

obclient> ALTER SYSTEM MAJOR FREEZE TENANT = all_user;
Query OK, 0 rows affected

Initiate a major compaction in the sys tenant for all meta tenants.

obclient> ALTER SYSTEM MAJOR FREEZE TENANT = all_meta;
Query OK, 0 rows affected

Initiate a major compaction in the sys tenant for tenant1 and tenant2.

obclient> ALTER SYSTEM MAJOR FREEZE TENANT = tenant1,tenant2;
Query OK, 0 rows affected

Minor compaction in the storage layer

Initiate a minor compaction in the sys tenant for the tenant itself.
```
obclient> ALTER SYSTEM MINOR FREEZE;
Query OK, 0 rows affected
```

Initiate a minor compaction in the sys tenant for all user tenants.

obclient> ALTER SYSTEM MINOR FREEZE TENANT = all_user;
Query OK, 0 rows affected

Initiate a minor compaction in the sys tenant for all meta tenants.

obclient> ALTER SYSTEM MINOR FREEZE TENANT = all_meta;
Query OK, 0 rows affected

Initiate a minor compaction in the sys tenant for tenant1 and tenant2.

obclient> ALTER SYSTEM MINOR FREEZE TENANT = tenant1,tenant2;
Query OK, 0 rows affected

Initiate a minor compaction in the sys tenant for a specified partition of tenant1.

obclient> ALTER SYSTEM MINOR FREEZE tenant = tenant1 tablet_id = 1100611139453887;
Query OK, 0 rows affected

Initiate a minor compaction in the sys tenant for a specified OBServer node.

obclient> ALTER SYSTEM MINOR FREEZE SERVER = ('10.XXX.XXX.XXX:2882');
Query OK, 0 rows affected

Initiate a minor compaction in the sys tenant for a specified log stream in a specified tenant.
```
obclient> ALTER SYSTEM MINOR FREEZE tenant = t1 LS 1;
Query OK, 0 rows affected
```
Initiate a minor compaction in the sys tenant for a specified log stream and partition in a specified tenant.
```
obclient> ALTER SYSTEM MINOR FREEZE tenant = t1 ls 1 tablet_id = 60000;
Query OK, 0 rows affected
```

Suspend or resume a major compaction

Suspend a major compaction in the sys tenant for all user tenants.

obclient> ALTER SYSTEM SUSPEND MERGE TENANT = all_user;
Query OK, 0 rows affected

Suspend a major compaction in the sys tenant for tenant1 and tenant2.

obclient> ALTER SYSTEM SUSPEND MERGE TENANT = tenant1,tenant2;
Query OK, 0 rows affected

Suspend a major compaction in the sys tenant for all meta tenants.

obclient> ALTER SYSTEM SUSPEND MERGE TENANT = all_meta;
Query OK, 0 rows affected

Resume a major compaction in the sys tenant for all user tenants.

obclient> ALTER SYSTEM RESUME MERGE TENANT = all_user;
Query OK, 0 rows affected

Resume a major compaction in the sys tenant for tenant1 and tenant2.

obclient> ALTER SYSTEM RESUME MERGE TENANT = tenant1,tenant2;
Query OK, 0 rows affected

Resume a major compaction in the sys tenant for all meta tenants.

obclient> ALTER SYSTEM RESUME MERGE TENANT = all_meta;
Query OK, 0 rows affected

Remove major compaction error tags

Remove major compaction error tags in the sys tenant for all user tenants.

obclient> ALTER SYSTEM CLEAR MERGE ERROR TENANT = all_user;
Query OK, 0 rows affected

Remove major compaction error tags in the sys tenant for tenant1 and tenant2.

obclient> ALTER SYSTEM CLEAR MERGE ERROR TENANT = tenant1,tenant2;
Query OK, 0 rows affected

Remove major compaction error tags in the sys tenant for all meta tenants.

obclient> ALTER SYSTEM CLEAR MERGE ERROR TENANT = all_meta;
Query OK, 0 rows affected

Initiate a partition-level major compaction

Query the tablet IDs of a table.

Here is an example:

SELECT t1.tenant_id, t2.tenant_name, t1.database_name, t1.table_id, t1.table_name, t1.tablet_id, t1.PARTITION_NAME, t1.SUBPARTITION_NAME
FROM oceanbase.CDB_OB_TABLE_LOCATIONS t1, oceanbase.DBA_OB_TENANTS t2
WHERE t1.tenant_id=t2.tenant_id
AND t1.table_name = 'test_tbl1'
AND t2.tenant_name = 'oracle001';

The return result is as follows:

+-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
| tenant_id | tenant_name | database_name | table_id | table_name | tablet_id | PARTITION_NAME | SUBPARTITION_NAME |
+-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200008 | P1             | SP0               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200009 | P1             | SP1               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200010 | P1             | SP2               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200011 | P1             | SP3               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200012 | P2             | SP4               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200013 | P2             | SP5               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200014 | P2             | SP6               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200015 | P2             | SP7               |
+-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
8 rows in set

For more information about columns in the view, see oceanbase.CDB_OB_TABLE_LOCATIONS.

Initiate a major compaction.

Here is an example:

ALTER SYSTEM MAJOR FREEZE TENANT = oracle001 TABLET_ID = 200008;

The return result is as follows:

Query OK, 0 rows affected

Initiate a partition-level minor compaction

Query the tablet IDs of a table.

Here is an example:

SELECT t1.tenant_id, t2.tenant_name, t1.database_name, t1.table_id, t1.table_name, t1.tablet_id, t1.PARTITION_NAME, t1.SUBPARTITION_NAME
FROM oceanbase.CDB_OB_TABLE_LOCATIONS t1, oceanbase.DBA_OB_TENANTS t2
WHERE t1.tenant_id=t2.tenant_id
AND t1.table_name = 'test_tbl1'
AND t2.tenant_name = 'oracle001';

The return result is as follows:

+-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
| tenant_id | tenant_name | database_name | table_id | table_name | tablet_id | PARTITION_NAME | SUBPARTITION_NAME |
+-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200008 | P1             | SP0               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200009 | P1             | SP1               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200010 | P1             | SP2               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200011 | P1             | SP3               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200012 | P2             | SP4               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200013 | P2             | SP5               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200014 | P2             | SP6               |
|      1004 | oracle001   | SYS           |   500011 | TEST_TBL1  |    200015 | P2             | SP7               |
+-----------+-------------+---------------+----------+------------+-----------+----------------+-------------------+
8 rows in set

For more information about columns in the view, see oceanbase.CDB_OB_TABLE_LOCATIONS.

Initiate a minor compaction.

Here is an example:

ALTER SYSTEM MINOR FREEZE TENANT = oracle001 TABLET_ID = 200008;

The return result is as follows:

Query OK, 0 rows affected

MAJOR and MINOR

Purpose

Syntax

Parameters

Note

Considerations

Examples

Major compaction in the storage layer

Minor compaction in the storage layer

Suspend or resume a major compaction

Remove major compaction error tags

Initiate a partition-level major compaction

Initiate a partition-level minor compaction

References