Online DDL: edit CONSTRAINT names in CREATE TABLE

[shlomi-noach]

Description

Followup to #10638 and #14385, this PR edits a CREATE TABLE statement, to remove the table-name prefix from existing constraint names. This is so as to make the constraint name a non-generated one. The reasoning is to avoid https://bugs.mysql.com/bug.php?id=107772

e.g. if some issues:

vtctldclient ApplySchema --ddl_strategy="vitess" --sql "create table mytable (id int primary key, check ((id >= 0)))" commerce

Then MySQL auto generates a constraint name, and the CREATE TABLE statement becomes:

CREATE TABLE `mytable` (
  `id` int NOT NULL,
  PRIMARY KEY (`id`),
  CONSTRAINT `mytable_chk_1` CHECK ((`id` >= 0))
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci

However, Online DDL intercepts the name mytable_chk_1, identifies that it begins with mytable_chk_, and converts it to something like chk_crq6muar52qehxxi5wmd4fj5y.

Related Issue(s)

https://bugs.mysql.com/bug.php?id=107772

Checklist

• "Backport to:" labels have been added if this change should be back-ported
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on the CI
• Documentation was added or is not required

Deployment Notes

[vitess-bot]

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[deepthi]

unrelated to this PR, but why do we pass a context to this function? Functions that don't perform RPCs do not need to take in a context.

[shlomi-noach]

This specific function indeed doesn't use the given context. There's many other non-gRPC functions that do use a context because they either use a Connection (context cancellation ensures connection terminates) or loops/waits.