Thirunarayanan Balathandayuthapani 687b18648c MDEV-35163 InnoDB persistent statistics fail to update after ALTER TABLE...ALGORITHM=COPY ...

Problem:
=======
- InnoDB statistics calculation for the table is done after
every 10 seconds by default in background thread dict_stats_thread()

- Doing multiple ALTER TABLE..ALGORITHM=COPY causes the
dict_stats_thread() to lag behind, therefore calculation of stats
for newly created intermediate table gets delayed

Fix:
====
- Stats calculation for newly created intermediate table is made
independent of background thread. After copying gets completed,
stats for new table is calculated as part of ALTER TABLE ... ALGORITHM=COPY.

dict_stats_rename_table(): Rename the table statistics from
intermediate table to new table

alter_stats_rebuild(): Removes the table name from the warning.
Because this warning can print for intermediate table as well.

Alter table using copy algorithm now calls alter_stats_rebuild()
under a shared MDL lock on a temporary #sql-alter- table,
differing from its previous use only during ALGORITHM=INPLACE
operations on user-visible tables.

dict_stats_schema_check(): Added a separate check for table
readability before checking for tablespace existence.
This could lead to detect of existence of persistent statistics
storage eariler and fallback to transient statistics.

This is a cherry-pick fix of mysql commit@cfe5f287ae99d004e8532a30003a7e8e77d379e3

2025-09-22 17:39:47 +05:30

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