MDEV-17901 Crash after instant DROP COLUMN of AUTO_INCREMENT column

We failed to reset the dict_table_t::persistent_autoinc after
instantly dropping an AUTO_INCREMENT column, causing a bogus
call to row_parse_int() on a subsequent insert.

mysql-test/suite/innodb/r/instant_alter.result

@@ -565,6 +565,19 @@ ALTER TABLE t1 DROP f2, ADD COLUMN f4 INT;
 ALTER TABLE t1 DROP f4;
 ALTER TABLE t1 DROP f1;
 DROP TABLE t1;
+CREATE TABLE t1 (id INT NOT NULL AUTO_INCREMENT, f INT, KEY(id)) ENGINE=InnoDB ROW_FORMAT=REDUNDANT;
+ALTER TABLE t1 DROP COLUMN id;
+INSERT INTO t1 () VALUES (),();
+SELECT * FROM t1;
+f
+NULL
+NULL
+ALTER TABLE t1 ADD COLUMN id INT NOT NULL AUTO_INCREMENT FIRST, ADD KEY(id);
+SELECT * FROM t1;
+id	f
+1	NULL
+2	NULL
+DROP TABLE t1;
 CREATE TABLE t1
 (id INT PRIMARY KEY, c2 INT UNIQUE,
 c3 POINT NOT NULL DEFAULT ST_GeomFromText('POINT(3 4)'),
@@ -1076,6 +1089,19 @@ ALTER TABLE t1 DROP f2, ADD COLUMN f4 INT;
 ALTER TABLE t1 DROP f4;
 ALTER TABLE t1 DROP f1;
 DROP TABLE t1;
+CREATE TABLE t1 (id INT NOT NULL AUTO_INCREMENT, f INT, KEY(id)) ENGINE=InnoDB ROW_FORMAT=COMPACT;
+ALTER TABLE t1 DROP COLUMN id;
+INSERT INTO t1 () VALUES (),();
+SELECT * FROM t1;
+f
+NULL
+NULL
+ALTER TABLE t1 ADD COLUMN id INT NOT NULL AUTO_INCREMENT FIRST, ADD KEY(id);
+SELECT * FROM t1;
+id	f
+1	NULL
+2	NULL
+DROP TABLE t1;
 CREATE TABLE t1
 (id INT PRIMARY KEY, c2 INT UNIQUE,
 c3 POINT NOT NULL DEFAULT ST_GeomFromText('POINT(3 4)'),
@@ -1587,10 +1613,23 @@ ALTER TABLE t1 DROP f2, ADD COLUMN f4 INT;
 ALTER TABLE t1 DROP f4;
 ALTER TABLE t1 DROP f1;
 DROP TABLE t1;
+CREATE TABLE t1 (id INT NOT NULL AUTO_INCREMENT, f INT, KEY(id)) ENGINE=InnoDB ROW_FORMAT=DYNAMIC;
+ALTER TABLE t1 DROP COLUMN id;
+INSERT INTO t1 () VALUES (),();
+SELECT * FROM t1;
+f
+NULL
+NULL
+ALTER TABLE t1 ADD COLUMN id INT NOT NULL AUTO_INCREMENT FIRST, ADD KEY(id);
+SELECT * FROM t1;
+id	f
+1	NULL
+2	NULL
+DROP TABLE t1;
 disconnect analyze;
 SELECT variable_value-@old_instant instants
 FROM information_schema.global_status
 WHERE variable_name = 'innodb_instant_alter_column';
 instants
-111
+114
 SET GLOBAL innodb_purge_rseg_truncate_frequency= @saved_frequency;

mysql-test/suite/innodb/t/instant_alter.test

@@ -437,6 +437,16 @@ ALTER TABLE t1 DROP f4;
 ALTER TABLE t1 DROP f1;
 DROP TABLE t1;
 
+# MDEV-17901 Crash after instant DROP COLUMN of AUTO_INCREMENT column
+eval CREATE TABLE t1 (id INT NOT NULL AUTO_INCREMENT, f INT, KEY(id)) $engine;
+ALTER TABLE t1 DROP COLUMN id;
+INSERT INTO t1 () VALUES (),();
+SELECT * FROM t1;
+# Adding AUTO_INCREMENT column will always require rebuild.
+ALTER TABLE t1 ADD COLUMN id INT NOT NULL AUTO_INCREMENT FIRST, ADD KEY(id);
+SELECT * FROM t1;
+DROP TABLE t1;
+
 dec $format;
 }
 disconnect analyze;

storage/innobase/handler/handler0alter.cc

@@ -173,6 +173,8 @@ inline void dict_table_t::prepare_instant(const dict_table_t& old,
 	DBUG_ASSERT(old.n_cols == old.n_def);
 	DBUG_ASSERT(n_cols == n_def);
 	DBUG_ASSERT(old.supports_instant());
+	DBUG_ASSERT(!persistent_autoinc
+		    || persistent_autoinc == old.persistent_autoinc);
 	/* supports_instant() does not necessarily hold here,
 	in case ROW_FORMAT=COMPRESSED according to the
 	MariaDB data dictionary, and ALTER_OPTIONS was not set.
@@ -431,6 +433,8 @@ inline void dict_table_t::instant_column(const dict_table_t& table,
 	DBUG_ASSERT(n_v_def == n_v_cols);
 	DBUG_ASSERT(table.n_v_def == table.n_v_cols);
 	DBUG_ASSERT(table.n_cols + table.n_dropped() >= n_cols + n_dropped());
+	DBUG_ASSERT(!table.persistent_autoinc
+		    || persistent_autoinc == table.persistent_autoinc);
 	ut_ad(mutex_own(&dict_sys->mutex));
 
 	{
@@ -6202,6 +6206,9 @@ prepare_inplace_alter_table_dict(
 			    == !!new_clustered);
 	}
 
+	DBUG_ASSERT(!ctx->need_rebuild()
+		    || !ctx->new_table->persistent_autoinc);
+
 	if (ctx->need_rebuild() && instant_alter_column_possible(
 		    *user_table, ha_alter_info, old_table)
 #if 1 // MDEV-17459: adjust fts_fetch_doc_from_rec() and friends; remove this
@@ -6330,6 +6337,11 @@ prepare_inplace_alter_table_dict(
 						   ctx->new_table, i),
 				   FTS_DOC_ID_COL_NAME)));
 
+		if (altered_table->found_next_number_field) {
+			ctx->new_table->persistent_autoinc
+				= ctx->old_table->persistent_autoinc;
+		}
+
 		ctx->prepare_instant();
 	}
 
@@ -6462,7 +6474,6 @@ prepare_inplace_alter_table_dict(
 		ut_ad(new_clust_index->n_core_null_bytes
 		      == UT_BITS_IN_BYTES(new_clust_index->n_nullable));
 
-		DBUG_ASSERT(!ctx->new_table->persistent_autoinc);
 		if (const Field* ai = altered_table->found_next_number_field) {
 			const unsigned	col_no = innodb_col_no(ai);
 
@@ -10142,8 +10153,8 @@ commit_cache_norebuild(
 		}
 
 		if (ha_alter_info->handler_flags & ALTER_DROP_STORED_COLUMN) {
-			dict_index_t* index = dict_table_get_first_index(
-				ctx->new_table);
+			const dict_index_t* index = ctx->new_table->indexes.start;
+
 			for (const dict_field_t* f = index->fields,
 				     * const end = f + index->n_fields;
 			     f != end; f++) {
@@ -10156,6 +10167,14 @@ commit_cache_norebuild(
 						      f->fixed_len);
 				}
 			}
+
+			DBUG_ASSERT(!ctx->instant_table->persistent_autoinc
+				    || ctx->new_table->persistent_autoinc
+				    == ctx->instant_table->persistent_autoinc);
+
+			if (!ctx->instant_table->persistent_autoinc) {
+				ctx->new_table->persistent_autoinc = 0;
+			}
 		}
 	}