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Re: [Commits] Rev 4275: MDEV-5867 ALTER TABLE t1 ENGINE=InnoDB keeps bad options when t1 ENGINE is CONNECT


Hi, Sergey!

On Jul 08, Sergey Vojtovich wrote:
> Hi Sergei,
> I believe options handling is way too confusing in general:
> - CREATE TABLE warns/errors about unknown options
> - ALTER TABLE ... ENGINE doesn't
> - CREATE TABLE ... LIKE doesn't

This is consistent. You get a warning or an error about options that you
explicitly specify, but not about options that are implicitly ihnerited.

> - different engines may assign different meaning to the same option
> - IGNORE_BAD_TABLE_OPTIONS doesn't actually _ignore_ _bad_ options but rather
>   _accepts_ _unkown_ options

Yes, I know :(

That's why I tried to say in the manual that SHOW CREATE TABLE *filters
out* invalid options, and IGNORE_BAD_TABLE_OPTIONS disables this
filtering, they are ignored and not filtered out.

> But the question is if we should show unknown options by default. I
> have no opinion: both cases are equally wrong to me.
> On the one hand we get unusable CREATE TABLE statement, on the other
> hand hidden metadata which may affect further statements.
> I'm fine with hidding unknown options that were accepted due to
> IGNORE_BAD_TABLE_OPTIONS, but hidding things that were accepted by
> fully successful ALTER TABLE statement sounds confusing.

Do you have a better idea?

My logic was - SHOW CREATE TABLE should generate a valid CREATE TABLE


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