Bug #23164 Query summary Warnings count capped at 65535
Submitted: 11 Oct 2006 6:08 Modified: 8 Apr 2010 6:41
Reporter: Clarence Risher Email Updates:
Status: Verified Impact on me:
None 
Category:MySQL Server: C API (client library) Severity:S3 (Non-critical)
Version:5.1.42, 4.1, 5.0, 5.1, 5.6.99 OS:Any (Mac OS X 10.6.3, Linux)
Assigned to: CPU Architecture:Any

[11 Oct 2006 6:08] Clarence Risher 
Description:
I ran a rather large LOAD DATA batch, and the results were as follows:

Query OK, 100498277 rows affected, 65535 warnings (2 hours 15 min 40.96 sec)
Records: 100498277  Deleted: 0  Skipped: 0  Warnings: 401993108

The first line appears to have its warnings count truncated to an unsigned short, or something similar.

How to repeat:
Run a warning-ful query.
[11 Oct 2006 11:33] Valeriy Kravchuk 
Thank you for a problem report. Please, try to repeat with a newer version, 5.0.26, and inform about the results. Did you use 64-bit OS/MySQL binaries?
[12 Nov 2006 0:00] Bugs System 
No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".
[6 Apr 2010 9:02] Walter Heck 
Still happening on at least Mac OS X 10.6.3 and MySQL 5.1.42:

MacBook-Pro:Downloads walterheck$ mysql -V
mysql  Ver 14.14 Distrib 5.1.42, for apple-darwin9.5.0 (i386) using readline 5.1

mysql> LOAD DATA INFILE '1000000.csv' INTO TABLE test.employees
    ->   FIELDS TERMINATED BY ',' ENCLOSED BY '"'
    ->   IGNORE 1 LINES
    -> (FirstName, LastName, Company, Address, City, County, State, ZIP, Phone, Fax, Email, Web);
Query OK, 1000000 rows affected, 65535 warnings (8.83 sec)
Records: 1000000  Deleted: 0  Skipped: 0  Warnings: 111710
[6 Apr 2010 15:01] Clarence Risher 
Re-opening, updating version and OS.
[8 Apr 2010 6:41] Sveta Smirnova 
Thank you for the feedback.

Verified as described reading source code:

there is definition in libmysql/libmysql.c:

uint STDCALL mysql_warning_count(MYSQL *mysql)

And this function used when client asks for warnings count.
[3 Oct 2016 9:53] Shahriyar Rzayev 
Still here. with 

select @@version;
+-----------------------+
| @@version             |
+-----------------------+
| 5.6.31-77.0-debug-log |
+-----------------------+
1 row in set (0.00 sec)

alter table dbtest.t1 modify `a` varchar(1);
Query OK, 200000 rows affected, 65535 warnings (43.22 sec)
Records: 200000  Duplicates: 0  Warnings: 200000
[4 Oct 2016 7:56] Georgi Kodinov 
Just for your information: fixing this would require incompatible protocol change in the OK packet that only has 2 bytes for the warnings count (http://dev.mysql.com/doc/internals/en/packet-OK_Packet.html).
[4 Oct 2016 8:10] Daniël van Eeden 
Related:
Bug #82696 	Warning count sometimes 2-bytes and sometimes 4-byte