Hi!
>>>>> "Yan" == Yan Yu <yan2yu2@stripped> writes:
<cut>
Yan> There are still many other broken test cases that we need to
Yan> investigate.
Yan> What is the bug ?
Yan> http://bugs.mysql.com/bug.php?id=49609
Thanks. Either MySQL people or MariaDB people will certainly take a
look at this.
<cut>
Monty> Most errors in this case should mainly be in the test suite.
Monty> If you run mysql-test-run --force and examine the results, ignoring
Monty> errors in the test suite, you should be able to get some assurance
Monty> that your change works.
Yan> Could you elaborate on what do you mean by "ignoring the errors in the test
> suite"? what kind of error I can ignore?
Yan> Currently I encounter three types of errors:
Yan> (1) most benign type of error is:
Yan> If I run mysql-test-run, some individual tests would fail; However, if I run a
> failed test by itself, using command:
Yan> mysql-test-run --record [single-test-name],
Yan> the test would succeed. I even tried to bundle several tests proceeding the
> failed test together with the failed
Yan> I assume I can ignore this type of error.
--record overwrites the old test data, so by using this, you may hide
a error.
What I would suggest you to do:
mysql-test-run --force
and after it's done, do a diff of the .result and .reject files in the
'r' directories.
You can ignore
- Only the characterset name in the result files has changed
(should be a majority of the cases)
- EXPLAIN statements where the key lengths are different..
- Test results where the order of lines has changed that depends on
the different sorting of character sets.
- Difference caused because of different max string lengths
(varchar/blob differences)
Any other test results you should try to understand what could cause
them.
Yan> (2) this type of error seems caused by MYSQL_TYPE_VAR_STRING vs. MYSQL_TYPE_BLOB.
Yan> for example, in sql/sql_select.cc, line 9456, function
> create_tmp_field_for_schema(),
Yan> based on item->max_length, it will create either a Field_blob object, or a
> Field_varstring object.
Yan> 9459 if (item->max_length > MAX_FIELD_VARCHARLENGTH)
Yan> 9460 field= new Field_blob(item->max_length, item->maybe_null,
Yan> 9461 item->name, item->collation.collation);
Yan> 9462 else
Yan> 9463 field= new Field_varstring(item->max_length, item->maybe_null,
Yan> 9464 item->name,
Yan> 9465 table->s,
> item->collation.collation);
Yan> if the system_charset_info is a multibyte encoding, e.g., utf8, the max_length of
> the column type would be greater than MAX_FIELD_VARCHARLENGTH, it will create an
> MYSQL_TYPE_BLOB object, otherwise, it will create an MYSQL_TYPE_VAR_STRING object if the
> system_charset_info is latin1.
Yan> The difference between MYSQL_TYPE_VAR_STRING vs. MYSQL_TYPE_BLOB manifests itself
> in at least two aspects:
Yan> (I) the "Type" of the COLUMN_TYPE returned to "describe/explain [table name]"
> command is different in these two cases.
Yan> this causes mysql_client_test fails.
This you can ignore.
Yan> (II) the wire format (i.e., packing results to the client) is different for these
> two fields: MYSQL_TYPE_VAR_STRING vs. MYSQL_TYPE_BLOB. Field_varstring::store() and
> Field_blob::store() in field.cc.
Yan> Somehow it seems like that the client got confused after I change
> system_charset_info to latin1, (I stepped traced the server code, it seems fine)
Should not cause a problem for the client (if there isn't an unknown
bug somewhere)
Yan> the results from "describe [table name] would miss information on two columns:
> Type and Null Column.
Yan> e.g., result for "describe Columns;" returns the following:
Yan> +--------------------------+------+------+-----+---------+-------+
Yan> | Field | Type | Null | Key | Default | Extra |
Yan> +--------------------------+------+------+-----+---------+-------+
Yan> | TABLE_CATALOG | | | | NULL | |
Yan> | TABLE_SCHEMA | | | | | |
Yan> | TABLE_NAME | | | | | |
Yan> | COLUMN_NAME | | | | | |
Yan> | ORDINAL_POSITION | | | | 0 | |
Yan> | COLUMN_DEFAULT | | | | NULL | |
Yan> I have not been able to pinpoint the root cause yet, BUT after I change
Yan> one line of ST_FIELD_INFO columns_fields_info[] from
Yan> + {"COLUMN_TYPE", 65535, MYSQL_TYPE_STRING, 0, 0, "Type", OPEN_FRM_ONLY},
Yan> to
Yan> - {"COLUMN_TYPE", 5000, MYSQL_TYPE_STRING, 0, 0, "Type", OPEN_FRM_ONLY},
Yan> the problem seems gone.
Yan> My Q is: would it be safe for me to make this change?
For your purpose, the above should be safe.
However, I need to look at what could cause the above display bug.
Yan> (3) problems caused by conversion between different charsets. mb_wc() or wc_mb()
Yan> our system_charset uses latin1, and
Yan> "create.test" includes the following SQL statement:
Yan> set names utf8;
Yan> create database
> имя_базы_в_кодировке_утф8_длиной_больше_чем_45;
Yan> use
> имя_базы_в_кодировке_утф8_длиной_больше_чем_45;
Yan> select database();
Yan>
> "имя_базы_в_кодировке_утф8_длиной_больше_чем_45" was
> converted to unicode string internally.
Yan> it seems like either the conversion is mis-handled somewhere, or the conversion is
> missing in one direction. Would this be possible?
This could be becase of two reasons
- files_charset_info needs to be utf8.
or
- files_charset_info needs to be same as system_charset_info.
Bar, can you answer this one ?
Yan> somehow, the database name is represented internally as
Yan> "???_????_?_?????????_???8_??????_??????_???_45",
Yan> and this same string is also returned back to the client for "select database();"
> command.
Yan> I do not know much about the unicode string, so not sure about the conversion
> code.
Regards,
Monty
