Will Dremio filter out databases with certain keywords in MySQL?

I found that using Dremio to connect to my MySQL database, some databases are not displayed in Dremio, including “information_schema” and “sys”. Among them, “information_schema” is not displayed, which is understandable because it is a system database, but sys is a database I created myself, but it happens to be called sys, but it is also not displayed in Dremio. Is this normal behavior? @balaji.ramaswamy

Is there any setting that may allow me to change this behavior?


@bigfacewo Looks like sys is by default a system database, see my show databases command output

mysql> show databases;
| Database           |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| testjson           |
5 rows in set (0.08 sec)


Let me see what SQL Dremio sends to MySQL for discovery and get back to you

@bigfacewo Dremio excludes hidden database, by default sys is a system generated database and is hidden, when you say you created a database called sys, did you first drop the system generated one? Is the sys database you created a hidden schema

@bigfacewo Just added my local mysql database and as expected no “sys”, when I look at sys database table via mysql I see a lot of system tables (101 tables), sample below so wondering how you were abe to create your own sys?

mysql> use sys;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
| Tables_in_sys                                 |
| host_summary                                  |
| host_summary_by_file_io                       |
| host_summary_by_file_io_type                  |
| host_summary_by_stages                        |
| host_summary_by_statement_latency             |
| host_summary_by_statement_type                |
| innodb_buffer_stats_by_schema                 |
| innodb_buffer_stats_by_table                  |