I am looking at mysql installation (Version 5.7.19). The mysqld is running and has innodb_file_per_table set to on. Looking at the tables using a mysql client shows up that tables all have engine "InnoDB" set. There are files ibdata1 and ibdata2 in innodb_data_file_path and also the .ibd files. I wondering now since it was my newbee understanding that innodb_files_per_table obsoltes the ibdata* files? Am I wrong or is the presence of the .ibd files and ibdata* files at the same time an indication for a mis-configured database?
1 Answer
ibdata1 stores InnoDB dictionary, undo segment(s), and doublewrite buffer. So, ibdata1 is needed regardless innodb_file_per_table setting.
ibdata*, that is a different question. (And it has been Asked and Answered many times.)