MDEV-23842 Atomic RENAME TABLE

- Major rewrite of ddl_log.cc and ddl_log.h
  - ddl_log.cc described in the beginning how the recovery works.
  - ddl_log.log has unique signature and is dynamic. It's easy to
    add more information to the header and other ddl blocks while still
    being able to execute old ddl entries.
  - IO_SIZE for ddl blocks is now dynamic. Can be changed without affecting
    recovery of old logs.
  - Code is more modular and is now usable outside of partition handling.
  - Renamed log file to dll_recovery.log and added option --log-ddl-recovery
    to allow one to specify the path & filename.
- Added ddl_log_entry_phase[], number of phases for each DDL action,
  which allowed me to greatly simply set_global_from_ddl_log_entry()
- Changed how strings are stored in log entries, which allows us to
  store much more information in a log entry.
- ddl log is now always created at start and deleted on normal shutdown.
  This simplices things notable.
- Added probes debug_crash_here() and debug_simulate_error() to simply
  crash testing and allow crash after a given number of times a probe
  is executed. See comments in debug_sync.cc and rename_table.test for
  how this can be used.
- Reverting failed table and view renames is done trough the ddl log.
  This ensures that the ddl log is tested also outside of recovery.
- Added helper function 'handler::needs_lower_case_filenames()'
- Extend binary log with Q_XID events. ddl log handling is using this
  to check if a ddl log entry was logged to the binary log (if yes,
  it will be deleted from the log during ddl_log_close_binlogged_events()
- If a DDL entry fails 3 time, disable it. This is to ensure that if
  we have a crash in ddl recovery code the server will not get stuck
  in a forever crash-restart-crash loop.

mysqltest.cc changes:
- --die will now replace $variables with their values
- $error will contain the error of the last failed statement

storage engine changes:
- maria_rename() was changed to be more robust against crashes during
  rename.

1 files changed, 8 insertions, 0 deletions

diff --git a/sql/debug_sync.h b/sql/debug_sync.h
index 3b8aa8815e1..4e3e10fcc51 100644
--- a/sql/debug_sync.h
+++ b/sql/debug_sync.h
@@ -53,4 +53,12 @@ static inline bool debug_sync_set_action(THD *, const char *, size_t)
 { return false; }
 #endif /* defined(ENABLED_DEBUG_SYNC) */
 
+#ifndef DBUG_OFF
+void debug_crash_here(const char *keyword);
+bool debug_simulate_error(const char *keyword, uint error);
+#else
+#define debug_crash_here(A) do { } while(0)
+#define debug_simulate_error(A, B) 0
+#endif
+
 #endif /* DEBUG_SYNC_INCLUDED */