MDEV-37886 PAGE_COMPRESSED ALTER TABLE operations inconsistent with innodb_file_per_table setting

[Thirunarayanan]

Problem:

InnoDB DDL does ALTER TABLE PAGE_COMPRESSED=1 because:

1. check_if_supported_inplace_alter() reads srv_file_per_table during precheck and does allow INSTANT operation.
2. User does change innodb_file_per_table later. But prepare phase read srv_file_per_table again during execution.
3. If the global variable changed between these phases, causes server abort for page_compressed tables.

Solution:

• Add a file_per_table member to Alter_inplace_info to capture the innodb_file_per_table value during the precheck phase and use that consistent value throughout the entire ALTER TABLE operation.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}