ddl: support all engine for temporary tables

[djshow832]

What problem does this PR solve?

Issue Number: close #28541

What is changed and how it works?

What's Changed: Support all kinds of engines on temporary tables.

This feature is not public yet, so we don't need a specific release note for this PR.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

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[REVIEW NOTIFICATION]

This pull request has been approved by:

• lcwangchao
• morgo

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[djshow832]

Found an unstable test #28816
Try to run again.

[lcwangchao]

Do we have to support all engines for temporary table or just allow engine innodb? If we allow engine memory , the current behavior is not compatible with that in mysql i.e: transaction.

[morgo]

Do we have to support all engines for temporary table or just allow engine innodb? If we allow engine memory , the current behavior is not compatible with that in mysql i.e: transaction.

Besides transactions, there are some other problems from lying about engine - memory supports hash and btree indexes; and the btree indexes are non-clustered, so the usage will differ.

But the documentation is at least pretty clear: https://docs.pingcap.com/tidb/stable/mysql-compatibility#storage-engines I think all is more consistent with the rest of TiDB for now.

[lcwangchao]

I found we did not persist engine in TableInfo and inference it from TempTableType . Should SHOW CREATE TABLE returns engine=innodb instead of engine=memory ?

[morgo]

It is closer to innodb than memory. Memory in MySQL means "heap storage engine" (non transactional)

…

On Sun., Oct. 17, 2021, 9:10 p.m. 王超, ***@***.***> wrote: ***@***.**** commented on this pull request. I found we did not persist engine in TableInfo and inference it from TempTableType . Should SHOW CREATE TABLE returns engine=innodb instead of engine=memory ? — You are receiving this because your review was requested. Reply to this email directly, view it on GitHub <#28815 (review)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAOE7SXJHMX65BZVGUU76LUHOFZ5ANCNFSM5F646D3Q> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[djshow832]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: d81eb52

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