Support SHOW SESSION STATUS LIKE "Compression";

[yahonda]

Feature Request

Since #36780 has been merged to master branch, tiup playground nightly supports MySQL compressed protocol.

To see if the compression is actually enabled or not, SHOW SESSION STATUS LIKE "Compression"; can be used for MySQL which is not available for TiDB yet. Refer to https://stackoverflow.com/questions/27427041/checking-connection-compression-usage

Describe the feature you'd like:
I wish TiDB support SHOW SESSION STATUS LIKE "Compression"; as MySQL does. Here are TiDB and MySQL behaviors.

--- TiDB

$ tiup playground nightly
$ mysql --comments --host 127.0.0.1 --port 4000 -u root --compress
mysql> SHOW SESSION STATUS LIKE "Compression";
Empty set (0.02 sec)

mysql>
mysql> select tidb_version()\G
*************************** 1. row ***************************
tidb_version(): Release Version: v7.2.0-alpha
Edition: Community
Git Commit Hash: be8d86504402cf6e9648fa4972d29e6ac3f9e9a8
Git Branch: heads/refs/tags/v7.2.0-alpha
UTC Build Time: 2023-06-05 14:25:17
GoVersion: go1.20.3
Race Enabled: false
Check Table Before Drop: false
Store: tikv
1 row in set (0.00 sec)

mysql>

--- MySQL

% mysql --comments --host 127.0.0.1 --port 3306 -u root --compress

WARNING: --compress is deprecated and will be removed in a future version. Use --compression-algorithms instead.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.33 Homebrew

Copyright (c) 2000, 2023, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> SHOW SESSION STATUS LIKE "compression";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Compression   | ON    |
+---------------+-------+
1 row in set (0.01 sec)

mysql> 

Describe alternatives you've considered:

\status is available for both TiDB and MySQL by cheking Protocol: Compressed. However, this feature is only available if the connection is made by mysql cli, not other application access like PHP with PDO::MYSQL_ATTR_COMPRESS.

% mysql --comments --host 127.0.0.1 --port 4000 -u root --compress

WARNING: --compress is deprecated and will be removed in a future version. Use --compression-algorithms instead.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 407
Server version: 8.0.11-TiDB-v7.2.0-alpha TiDB Server (Apache License 2.0) Community Edition, MySQL 8.0 compatible

Copyright (c) 2000, 2023, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> \status
--------------
mysql  Ver 8.0.33 for macos13.3 on x86_64 (Homebrew)

Connection id:		407
Current database:
Current user:		root@127.0.0.1
SSL:			Cipher in use is TLS_AES_128_GCM_SHA256
Current pager:		stdout
Using outfile:		''
Using delimiter:	;
Server version:		8.0.11-TiDB-v7.2.0-alpha TiDB Server (Apache License 2.0) Community Edition, MySQL 8.0 compatible
Protocol version:	10
Connection:		127.0.0.1 via TCP/IP
Server characterset:	utf8mb4
Db     characterset:	utf8mb4
Client characterset:	utf8mb4
Conn.  characterset:	utf8mb4
TCP port:		4000
Protocol:		Compressed
Binary data as:		Hexadecimal
Uptime:			3 min 2 sec

Threads: 0  Questions: 0  Slow queries: 0  Opens: 0  Flush tables: 0  Open tables: 0  Queries per second avg: 0.000
--------------

Teachability, Documentation, Adoption, Migration Strategy:

[xuyukeviki]

Can I implement this now？

[xuyukeviki]

/assign

[dveeden]

This would be very useful. Note that MySQL has 3 session variables for this.

sql> SHOW SESSION STATUS LIKE 'Compression%';
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| Compression           | OFF   |
| Compression_algorithm |       |
| Compression_level     | 0     |
+-----------------------+-------+
3 rows in set (0.0029 sec)

sql> SELECT VERSION();
+-----------+
| VERSION() |
+-----------+
| 8.0.33    |
+-----------+
1 row in set (0.0007 sec)

[dveeden]

@xuyukeviki any progress? anything I can do to help?

[dveeden]

@xuyukeviki any update on this?