MySQL Bugs: #40163: mysql's help is confusing when trying to get information about storage engines

Bug #40163	mysql's help is confusing when trying to get information about storage engines
Submitted:	20 Oct 2008 8:41	Modified:	26 Nov 2008 16:54
Reporter:	Olav Sandstå	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	6.0.7, 5.1.29, 5.0.70	OS:	Any
Assigned to:	Paul DuBois	CPU Architecture:	Any

Description:
After starting the mysql client and trying to use its help command to get information about Storage Engines it seems to have this as a topic but it is hard to get anything useful from it.

Copy of my attempt:

mysql> help contents
You asked for help about help category: "Contents"
For more information, type 'help <item>', where <item> is one of the following
categories:
   Account Management
   Administration
   Compound Statements
   Data Definition
   Data Manipulation
   Data Types
   Functions
   Functions and Modifiers for Use with GROUP BY
   Geographic Features
   Language Structure
   Plugins
   Storage Engines
   Table Maintenance
   Transactions
   User-Defined Functions
   Utility

mysql> help Storage Engines

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help "Storage Engines"

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help 'Storage Engines'
You asked for help about help category: "BLACKHOLE"
For more information, type 'help <item>', where <item> is one of the following
topics:
   YES
topics:
   YES
topics:
   DEFAULT
topics:
   YES
topics:
   YES
topics:
   YES
topics:
   YES
topics:
   YES

mysql>

How to repeat:
1. Start mysql
2. Run the commands above

Suggested fix:
I would have liked both the following commands:

   help "Storage Engines"
   help 'Storage Engines'

to write out the expected help text.

Thank you for the report.

Verified as described, although help 'Storage engines' doesn't work for me:

mysql> help contents
You asked for help about help category: "Contents"
For more information, type 'help <item>', where <item> is one of the following
categories:
   Account Management
   Administration
   Compound Statements
   Data Definition
   Data Manipulation
   Data Types
   Functions
   Functions and Modifiers for Use with GROUP BY
   Geographic Features
   Language Structure
   Plugins
   Storage Engines
   Table Maintenance
   Transactions
   User-Defined Functions
   Utility

mysql> help Storage Engines

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help 'Storage Engines'
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'Your MySQL connection id is 173
Server version: 6.0.8-alpha-debug Source distrib' at line 1
mysql> help  "Storage Engines"

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help 'Storage Engines';

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help   Account Management
You asked for help about help category: "Account Management"
For more information, type 'help <item>', where <item> is one of the following
topics:
   CREATE USER
   DROP USER
   GRANT
   RENAME USER
   REVOKE
   SET PASSWORD

mysql>

Client of 5.1.x is also affected:

C:\Program Files\MySQL\MySQL Server 5.0\bin>mysql -uroot -proot -P3310 test
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 24
Server version: 5.1.29-rc-community MySQL Community Server (GPL)

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> help 'Storage Engines';

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help Storage Engines;

Nothing found
Please try to run 'help contents' for a list of all accessible topics

mysql> help contents;
You asked for help about help category: "Contents"
For more information, type 'help <item>', where <item> is one of the following
categories:
   Account Management
   Administration
   Data Definition
   Data Manipulation
   Data Types
   Functions
   Functions and Modifiers for Use with GROUP BY
   Geographic Features
   Language Structure
   Plugins
   Storage Engines
   Stored Routines
   Table Maintenance
   Transactions
   Triggers
   Utility

This doesn't seem to be a code bug; client correctly sends request to server, server goes through sql_help.cc::mysqld_help(). fill_help_tables.sql sets up the category

insert into help_category (help_category_id,name,parent_category_id,url) values (16,"Storage Engines",30,'');

but then seems to put no data in #16. IOW, client and server correctly report that there were no sub-entries found. By that token, this is a docs "bug", and "Storage Engines" should probably either get entries, or be disabled (presumably by re-parenting it away from #30?) until it gets entries?

PS repository still only contains the stand-in fill_help_tables.sql ?

This is most likely a function of the help-file content, which is created from the reference manual. It might be that there simply are no sub-topics for "Storage Engines." I'll check this out and remove the topic if that is so.

Recategorizing to Documentation and assigning to myself.

Thank you for your bug report. This issue has been addressed in the documentation. The updated documentation will appear on our website shortly, and will be included in the next release of the relevant products.

There were no subtopics for the Storage Engine category. I removed the category.