MDEV-18518 Multi-table CREATE and DROP transactions for InnoDB

InnoDB used to support at most one CREATE TABLE or DROP TABLE
per transaction. This caused complications for DDL operations on
partitioned tables (where each partition is treated as a separate
table by InnoDB) and FULLTEXT INDEX (where each index is maintained
in a number of internal InnoDB tables).

dict_drop_index_tree(): Extend the MDEV-24589 logic and treat
the purge or rollback of SYS_INDEXES records of clustered indexes
specially: by dropping the tablespace if it exists. This is the only
form of recovery that we will need.

trx_undo_ddl_type: Document the DDL undo log record types better.

trx_t::dict_operation: Change the type to bool.

trx_t::ddl: Remove.

trx_t::table_id, trx_undo_t::table_id: Remove.

dict_build_table_def_step(): Remove trx_t::table_id logging.

dict_table_close_and_drop(), row_merge_drop_table(): Remove.

row_merge_lock_table(): Merged to the only callers, which can
call lock_table_for_trx() directly.

fts_aux_table_t, fts_aux_id, fts_space_set_t: Remove.

fts_drop_orphaned_tables(): Remove.

row_merge_rename_index_to_drop(): Remove. Thanks to MDEV-24589,
we can simply delete the to-be-dropped indexes from SYS_INDEXES,
while still being able to roll back the operation.

ha_innobase_inplace_ctx: Make a few data members const.
Preallocate trx.

prepare_inplace_alter_table_dict(): Simplify the logic. Let the
normal rollback take care of some cleanup.

row_undo_ins_remove_clust_rec(): Simplify the parsing of SYS_COLUMNS.

trx_rollback_active(): Remove the special DROP TABLE logic.

trx_undo_mem_create_at_db_start(), trx_undo_reuse_cached():
Always write TRX_UNDO_TABLE_ID as 0.

1 files changed, 16 insertions, 49 deletions

diff --git a/storage/innobase/trx/trx0trx.cc b/storage/innobase/trx/trx0trx.cc
index ca868cab2e9..11cceda8529 100644
--- a/storage/innobase/trx/trx0trx.cc
+++ b/storage/innobase/trx/trx0trx.cc
@@ -113,9 +113,7 @@ trx_init(
 
 	trx->lock.n_rec_locks = 0;
 
-	trx->dict_operation = TRX_DICT_OP_NONE;
-
-	trx->table_id = 0;
+	trx->dict_operation = false;
 
 	trx->error_state = DB_SUCCESS;
 
@@ -133,8 +131,6 @@ trx_init(
 
 	trx->will_lock = 0;
 
-	trx->ddl = false;
-
 	trx->internal = false;
 
 	trx->bulk_insert = false;
@@ -383,7 +379,7 @@ void trx_t::free()
   ut_ad(!read_only);
   ut_ad(!lock.wait_lock);
 
-  dict_operation= TRX_DICT_OP_NONE;
+  dict_operation= false;
   trx_sys.deregister_trx(this);
   assert_freed();
   trx_sys.rw_trx_hash.put_pins(this);
@@ -423,7 +419,6 @@ void trx_t::free()
   MEM_NOACCESS(&start_time, sizeof start_time);
   MEM_NOACCESS(&start_time_micro, sizeof start_time_micro);
   MEM_NOACCESS(&commit_lsn, sizeof commit_lsn);
-  MEM_NOACCESS(&table_id, sizeof table_id);
   MEM_NOACCESS(&mysql_thd, sizeof mysql_thd);
   MEM_NOACCESS(&mysql_log_file_name, sizeof mysql_log_file_name);
   MEM_NOACCESS(&mysql_log_offset, sizeof mysql_log_offset);
@@ -448,7 +443,6 @@ void trx_t::free()
   MEM_NOACCESS(&fts_trx, sizeof fts_trx);
   MEM_NOACCESS(&fts_next_doc_id, sizeof fts_next_doc_id);
   MEM_NOACCESS(&flush_tables, sizeof flush_tables);
-  MEM_NOACCESS(&ddl, sizeof ddl);
   MEM_NOACCESS(&internal, sizeof internal);
 #ifdef UNIV_DEBUG
   MEM_NOACCESS(&start_line, sizeof start_line);
@@ -693,13 +687,7 @@ static void trx_resurrect(trx_undo_t *undo, trx_rseg_t *rseg,
   trx->is_recovered= true;
   trx->start_time= start_time;
   trx->start_time_micro= start_time_micro;
-
-  if (undo->dict_operation)
-  {
-    trx_set_dict_operation(trx, TRX_DICT_OP_TABLE);
-    if (!trx->table_id)
-      trx->table_id= undo->table_id;
-  }
+  trx->dict_operation= undo->dict_operation;
 
   trx_sys.rw_trx_hash.insert(trx);
   trx_sys.rw_trx_hash.put_pins(trx);
@@ -941,7 +929,7 @@ trx_start_low(
 	trx->auto_commit = thd_trx_is_auto_commit(trx->mysql_thd);
 
 	trx->read_only = srv_read_only_mode
-		|| (!trx->ddl && !trx->internal
+		|| (!trx->dict_operation && !trx->internal
 		    && thd_trx_is_read_only(trx->mysql_thd));
 
 	if (!trx->auto_commit) {
@@ -973,7 +961,7 @@ trx_start_low(
 	list too. */
 
 	if (!trx->read_only
-	    && (trx->mysql_thd == 0 || read_write || trx->ddl)) {
+	    && (!trx->mysql_thd || read_write || trx->dict_operation)) {
 
 		/* Temporary rseg is assigned only if the transaction
 		updates a temporary table */
@@ -1434,7 +1422,7 @@ inline void trx_t::commit_in_memory(const mtr_t *mtr)
   lock.was_chosen_as_deadlock_victim= false;
 #endif /* WITH_WSREP */
   mutex.wr_lock();
-  dict_operation= TRX_DICT_OP_NONE;
+  dict_operation= false;
 
   DBUG_LOG("trx", "Commit in memory: " << this);
   state= TRX_STATE_NOT_STARTED;
@@ -2192,38 +2180,17 @@ trx_start_internal_read_only_low(
 	trx_start_low(trx, false);
 }
 
-/*************************************************************//**
-Starts the transaction for a DDL operation. */
-void
-trx_start_for_ddl_low(
-/*==================*/
-	trx_t*		trx,	/*!< in/out: transaction */
-	trx_dict_op_t	op)	/*!< in: dictionary operation type */
+/** Start a transaction for a DDL operation.
+@param trx   transaction */
+void trx_start_for_ddl_low(trx_t *trx)
 {
-	switch (trx->state) {
-	case TRX_STATE_NOT_STARTED:
-		/* Flag this transaction as a dictionary operation, so that
-		the data dictionary will be locked in crash recovery. */
-
-		trx_set_dict_operation(trx, op);
-
-		/* Ensure it is not flagged as an auto-commit-non-locking
-		transation. */
-		trx->will_lock = 1;
-
-		trx->ddl= true;
-
-		trx_start_internal_low(trx);
-		return;
-
-	case TRX_STATE_ACTIVE:
-	case TRX_STATE_PREPARED:
-	case TRX_STATE_PREPARED_RECOVERED:
-	case TRX_STATE_COMMITTED_IN_MEMORY:
-		break;
-	}
-
-	ut_error;
+  ut_a(trx->state == TRX_STATE_NOT_STARTED);
+  /* Flag this transaction as a dictionary operation, so that
+  the data dictionary will be locked in crash recovery. */
+  trx->dict_operation= true;
+  /* Ensure it is not flagged as an auto-commit-non-locking transaction. */
+  trx->will_lock= 1;
+  trx_start_internal_low(trx);
 }
 
 /*************************************************************//**