fixed Cannot read property 'COLUMN_NAME' of undefined

[DoubleSpout]

bug review: because i have modify the table name

fixed the bug~

I want to start from specify binlogfile and specify postion, so I have modified the startAtEnd Parameter, use it like this:

zongji.start({
    includeEvents: ['rotate', 'tablemap', 'writerows', 'updaterows', 'deleterows'],
    startAtEnd: {
        filename: 'binlog.000001',
        position: 1002,
    },
});

if startAtEnd assignment boolean, it works as well as before.
finally, thanks for your zongji module, I like it !

[nevill]

@DoubleSpout Thanks for your feedback. I can reproduce the bug too. But I cannot make it working even with your Fix, let me figure it out later ...
BTW, can you use 2-space indent in your PR (that's what we do in this project)? And, it would be perfect if you could provide some unit tests. 😸

[nevill]

I think we have a big Try ... catch block somewhere, to catch all the errors during parsing, not necessary here. Yeah, I'd like to have Try ... catch as few as possible. (even though, I'm not a Java Hater 😉 )

[jmealo]

Not performing this operation causes invalid data structures that still crash Zongji later on. We need to figure out why the length of an array is zero, when we expect a non-zero length.

It seems like we're parsing a tablemap wrong. If we bail from parsing it, we get the event following the tablemap and crash anyway.

@nevill Is that what you think is going on as well?

[jmealo]

@nevill The SQL query in fetchTableInfo sometimes returns 0 rows which is the cause of this error. When I run the query by hand, it returns the expected number of rows.

The query is a bit different in my fork since I added additional metadata. My query is also having the same issue.

 SELECT c.COLUMN_NAME, COLLATION_NAME, CHARACTER_SET_NAME, COLUMN_COMMENT, COLUMN_TYPE, IS_NULLABLE, t.CONSTRAINT_TYPE, k.ORDINAL_POSITION, k.CONSTRAINT_NAME FROM information_schema.columns c LEFT JOIN information_schema.KEY_COLUMN_USAGE k ON k.TABLE_NAME = c.TABLE_NAME AND k.TABLE_SCHEMA = c.TABLE_SCHEMA AND k.COLUMN_NAME = c.COLUMN_NAME LEFT JOIN information_schema.TABLE_CONSTRAINTS t ON t.TABLE_NAME = c.TABLE_NAME AND t.CONSTRAINT_SCHEMA = c.TABLE_SCHEMA AND t.CONSTRAINT_NAME = k.CONSTRAINT_NAME WHERE c.TABLE_SCHEMA = "<<schema>>" AND c.TABLE_NAME = "<<table>>"

[jmealo]

In _fetchTableInfo:

  this.ctrlConnection.query(sql, function(err, rows) {
    if (err) {
      // Errors should be emitted
      self.emit('error', err);
      return;
    }

We might as well throw/die here because if we don't call next() Zongji will stop processing binlog events.

[jmealo]

From the MySQL manual:
"Each MySQL user has the right to access these tables, but can see only the rows in the tables that correspond to objects for which the user has the proper access privileges. In some cases (for example, the ROUTINE_DEFINITION column in the INFORMATION_SCHEMA.ROUTINES table), users who have insufficient privileges will see NULL."

[felipesmendes]

I had the same issue using Mysql-Events package:

mysql-events

Someone solved?

[hamza610]

Has there been a resolution yet?
I updated my MySQL version to 5.7 from 5.5 and encountered this issue and when I reverted back to 5.5 the issue disappeared.

[millenovecento]

Hi All, to fix the problem for mysql 5.7 i added " order by c.ORDINAL_POSITION" to tableInfoQueryTemplate in index.js.

[nevill]

Closing it because many things changed.

[jmealo]

@nevill: Awesome, I haven't been keeping up to date with the project. I'm sure my 12/17/15 comment has to do with the root cause, which technically isn't a bug in the software but an environmental issue. It might be worth adding a special error message or tips in the documentation.

[rodrigogs]

It seems that mysql lib is return a wrong parseLengthCodedNumber. I wonder if it's ok to just assume the column length from the actual column array.

[taieb-tk]

Sorry for asking on a closed 4 year old thread. But this problem is occuring for me as well, seems like parseLengthCodedNumber -> Has the wrong length. The reason for it seems to be when i have a unique constraint in db. When i remove it, it works....