maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Sergey!

On Feb 24, Sergey Vojtovich wrote:
> revision-id: 59e1aaa5f71cb725ce5242eb5abf2e00c6f5a793 (mariadb-10.1.8-124-g59e1aaa)
> parent(s): 0485328d030f4b742dac7b667e8ed099beb9e9f2
> committer: Sergey Vojtovich
> timestamp: 2016-02-24 14:31:43 +0400
> message:
> 
> +static ST_FIELD_INFO user_variables_fields_info[] =
> +{
> +  { "VARIABLE_NAME", 64, MYSQL_TYPE_STRING, 0, 0, "Variable_name", 0 },
> +  { "VARIABLE_VALUE", 2048, MYSQL_TYPE_STRING, 0, MY_I_S_MAYBE_NULL, "Value", 0 },
> +  { 0, 0, MYSQL_TYPE_NULL, 0, 0, 0, 0 }
> +};

1. As discussed on irc, let's show everything we know about variables.
   Hmm, let me see what's in user_var_entry structure...
   The type, the character set, signed/unsigned.
   I think, query_id would be not very useful, though.
   See COLUMNS and SYSTEM_VARIABLES for appropriate column names.

2. You have defined old_name's for columns - "Variable_name" and
   "Value". This automatically enables SHOW USER_VARIABLES statement.
   See https://mariadb.com/kb/en/mariadb/information-schema-plugins-show-and-flush-statements/
   You shouldn't enable SHOW if it displays exactly the same content as
   I_S.USER_VARIABLES. But if you'll add all the other metadata fields
   to the I_S table, then SHOW could be used to display a subset of the
   columns, e.g. only variable name and the value. Just as you have now :)

3. An interesting extension could be a FLUSH USER_VARIABLES statement
   that would empty the thd->user_vars hash. It's very easy to do,
   but I don't know if it'll be very useful :)
   See the url above for the API.

Regards,
Sergei
Chief Architect MariaDB
and security@xxxxxxxxxxx