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The MySQL Worklog are design specifications for some of the items that may be considered for future development.

WL#4797: Extending protocol's OK packet

Affects: Server-Prototype Only — Status: Un-Assigned — Priority: Medium

Description

For several commands (e.g. SET NAMES, SET character_set, USE database, SET
SQL_MODE) the client receives an ok packet only without information about server
status changes: e.g. after SET NAMES big5 the server assumes that the client
will send big5 encoded data, while the client character set is still latin1 (see
http://lists.mysql.com/announce/364).

Proposal: extend the OK packet to allow server to send more information.

Bytes                       Name
 -----                       ----
 1   (Length Coded Binary)   field_count, always = 0
 1-9 (Length Coded Binary)   affected_rows
 1-9 (Length Coded Binary)   insert_id
 2                           server_status
 2                           warning_count
 n   (until end of packet)   message

if server_status has a flag SERVER_STATUS_CHANGED server will send after
warning_count

 1                           enum key (CHANGED_SQLMODE, CHANGED_SCHEMA, 
                                       CHANGED_CHARSET, ....)
 n   (until end of packet)   data: e.g charset no, new sql_mode, database name

List of server changes we need to transmit:
- client character set
- current database
- sql_mode

Related bugs:

BUG#32271: mysql client unicode output incorrectly padded