Bug #107603 new dd::Table has no se_private_data in ha::inlpace_alter

• Submitted: 20 Jun 2022 7:30
• Modified: 20 Jun 2022 12:11
• Reporter: Siyuan Ren
• Status: Not a Bug
• Category: MySQL Server: DDL
• Severity: S3 (Non-critical)
• Version: 8.0.27
• OS: Any
• CPU Architecture: Any
• Tags: DDL

[20 Jun 2022 7:30] Siyuan Ren

Description:
NOT a bug, just throw a question.

mysql_alter_table() {
  create_table_impl(no_ha_table=true, &non_dd_table_def);
  dd::Table *table_def = non_dd_table_def.get();
  mysql_inplace_alter_table(altered_table_def=table_def)
    ha_commit_inplace_alter_table(new_table_def=altered_table_def);

  /* ALTER TABLE using copy algorithm. */
  ha_create_table();
}

In __INPLACE__ path, we have ha::*inplace_alter_table(dd::Table *new_table_def) which allows SE (with atomic DDL support) to adjust its own specific metadata in se_private_*.
However, in the code path above, new_table_def has empty se_private_data, since there is the only invocation of ha::create() in __COPY__ path, rather than in __INPLACE__ path.
So basically, is it designed intentionally, and based on what consideration?

How to repeat:
read the code.

[20 Jun 2022 12:11] MySQL Verification Team

Hi Mr. Ren,

Thank you for your bug report.

However , it is not a bug.

The code is arranged as is, because COPY is a default behaviour, while INPLACE has to satisfy a number of the conditions in order to be allowed.

This is all described in our Reference Manual.