Certain schemas(?) don't work with events.

[Scusemua]

It seems that certain table schemas do not work well with NDB events. That is, if you create a table with a particular schema and then create an event on that table, some of the column values will always be undefined when you receive that event.

After looking through the code a little, I think it might have to do with buffer alignment issues and type sizes? Something about when the NdbRecAttr objects are created. But I don't really know.

Reproducability:

Using the following schema, create a table:

CREATE TABLE `example` (
    `column1` BIGINT NOT NULL,
    `column2` INT NOT NULL,
    `column3` TINYINT  NOT NULL,
    `column4` BIGINT NOT NULL,
    `column5` BIGINT NOT NULL,
    `column6` BIGINT NOT NULL,
    PRIMARY KEY (`column1`, `column4`, `column6`)
) ENGINE=NDB DEFAULT CHARSET=latin1 COLLATE=latin1_general_cs;

You can use this modified version of ndb_apievent.cpp to test: https://pastebin.com/jsLcffnQ

Or you can use your own program/modify the example yourself. Just specify the name of the table created above and use the same event columns. I created an event and specified "column1", "column2", "column3", "column4". For every received event (INSERT, UPDATE, DELETE), the pre- and post-values for "column2" and "column3" will be undefined.

Observations:

• If I specify all of the columns, then they all receive values correctly.
• If the primary key is set to just column1, then the event described above works.
• Likewise, the event works if the primary key is set to (column1, column4).

If this is intended behavior, then maybe it could be documented a little more clearly?