MDEV-14378 In ALGORITHM=INPLACE, use a common name for the intermediate tables or partitions

This is a backport of commit 07e9ff1fe18999e1acd640ee3b2169c3f506fb35.

Allow DROP TABLE `#mysql50##sql-...._.` to drop tables that were
being rebuilt by ALGORITHM=INPLACE

NOTE: If the server is killed after the table-rebuilding ALGORITHM=INPLACE
commits inside InnoDB but before the .frm file has been replaced, then
the recovery will involve something else than DROP TABLE.

NOTE: If the server is killed in a true inplace ALTER TABLE commits
inside InnoDB but before the .frm file has been replaced, then we
are really out of luck. To properly handle that situation, we would
need a transactional mysql.ddl_fixup table that directs recovery to
rename or remove files.

prepare_inplace_alter_table_dict(): Use the altered_table->s->table_name
for generating the new_table_name.

table_name_t::part_suffix: The start of the partition name suffix.

table_name_t::dbend(): Return the end of the schema name.

table_name_t::dblen(): Return the length of the schema name, in bytes.

table_name_t::basename(): Return the name without the schema name.

table_name_t::part(): Return the partition name, or NULL if none.

row_drop_table_for_mysql(): Assert for #sql, not #sql-ib.

5 files changed, 45 insertions, 12 deletions

diff --git a/storage/innobase/dict/dict0mem.cc b/storage/innobase/dict/dict0mem.cc
index dcf52c93de1..bde8303ead5 100644
--- a/storage/innobase/dict/dict0mem.cc
+++ b/storage/innobase/dict/dict0mem.cc
@@ -50,6 +50,14 @@ static const char* innobase_system_databases[] = {
 	NullS
 };
 
+/** The start of the table basename suffix for partitioned tables */
+const char table_name_t::part_suffix[4]
+#ifdef _WIN32
+= "#p#";
+#else
+= "#P#";
+#endif
+
 /** An interger randomly initialized at startup used to make a temporary
 table name as unuique as possible. */
 static ib_uint32_t	dict_temp_file_num;
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 0fdfaa449fd..7bb84b41a11 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -294,11 +294,7 @@ is_partition(
 {
 	/* We look for pattern #P# to see if the table is partitioned
 	MariaDB table. */
-#ifdef _WIN32
-	return strstr(file_name, "#p#");
-#else
-	return strstr(file_name, "#P#");
-#endif /* _WIN32 */
+	return strstr(file_name, table_name_t::part_suffix);
 }
 
 /** Signal to shut down InnoDB (NULL if shutdown was signaled, or if
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index 8565cad96ec..412438237fa 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -4520,11 +4520,18 @@ prepare_inplace_alter_table_dict(
 	to rebuild the table with a temporary name. */
 
 	if (new_clustered) {
-		const char*	new_table_name
-			= dict_mem_create_temporary_tablename(
-				ctx->heap,
-				ctx->new_table->name.m_name,
-				ctx->new_table->id);
+		size_t	dblen = ctx->old_table->name.dblen() + 1;
+		size_t	tablen = altered_table->s->table_name.length;
+		const char* part = ctx->old_table->name.part();
+		size_t	partlen = part ? strlen(part) : 0;
+		char*	new_table_name = static_cast<char*>(
+			mem_heap_alloc(ctx->heap,
+				       dblen + tablen + partlen + 1));
+		memcpy(new_table_name, ctx->old_table->name.m_name, dblen);
+		memcpy(new_table_name + dblen,
+		       altered_table->s->table_name.str, tablen);
+		memcpy(new_table_name + dblen + tablen,
+		       part ? part : "", partlen + 1);
 		ulint		n_cols = 0;
 		ulint		n_v_cols = 0;
 		dtuple_t*	add_cols;
diff --git a/storage/innobase/include/dict0mem.h b/storage/innobase/include/dict0mem.h
index 44d1a11ab33..fc120149c5f 100644
--- a/storage/innobase/include/dict0mem.h
+++ b/storage/innobase/include/dict0mem.h
@@ -568,6 +568,29 @@ struct table_name_t
 {
 	/** The name in internal representation */
 	char*	m_name;
+
+	/** @return the end of the schema name */
+	const char* dbend() const
+	{
+		const char* sep = strchr(m_name, '/');
+		ut_ad(sep);
+		return sep;
+	}
+
+	/** @return the length of the schema name, in bytes */
+	size_t dblen() const { return dbend() - m_name; }
+
+	/** Determine the filename-safe encoded table name.
+	@return	the filename-safe encoded table name */
+	const char* basename() const { return dbend() + 1; }
+
+	/** The start of the table basename suffix for partitioned tables */
+	static const char part_suffix[4];
+
+	/** Determine the partition or subpartition name suffix.
+	@return the partition name
+	@retval	NULL	if the table is not partitioned */
+	const char* part() const { return strstr(basename(), part_suffix); }
 };
 
 /** Data structure for a column in a table */
diff --git a/storage/innobase/row/row0mysql.cc b/storage/innobase/row/row0mysql.cc
index 4677dfc296a..58d90cfb2ac 100644
--- a/storage/innobase/row/row0mysql.cc
+++ b/storage/innobase/row/row0mysql.cc
@@ -3629,8 +3629,7 @@ row_drop_table_for_mysql(
 		TRX_DICT_OP_INDEX, we should be dropping auxiliary
 		tables for full-text indexes or temp tables. */
 		ut_ad(strstr(table->name.m_name, "/FTS_")
-		      || strstr(table->name.m_name,
-				"/" TEMP_FILE_PREFIX_INNODB));
+		      || strstr(table->name.m_name, TEMP_TABLE_PATH_PREFIX));
 	}
 
 	/* Mark all indexes unavailable in the data dictionary cache