Using System Monitoring Views

System views are used to track database objects (as part of the Database Catalog Data), system static configuration (as part of the System Catalog Data) and dynamic metrics on the system performance (as part of the Dynamic System Data).

The system monitoring views are exposed by the SHOW commands. Those SHOW commands are Regatta proprietary commands and support the options listed below.

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Synopsis

SHOW view_name [ LIKE 'pattern' ][ IN object_type object_name ] [ ROWS BETWEEN n AND m ]

where object_type is:
{ TABLE | INDEX | DEVICE }

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Parameters

view_name

The system catalog view name.

LIKE '<pattern>'

Filters the view output by its main object (e.g filter by table name in SHOW TABLES view, filter by index name in SHOW INDEXES view). The filter uses case-sensitive pattern matching, with the support of optional leading and/or trailing percent signs.

The percent sign (%) stands for sequences of zero or more characters.

IN object_type object_name

Show only results within the scope of a specific object in the relevant system view data. Possible object types and the views to which they apply:

The table_name/index_name/device_id should be the fully-qualified name.

Note that input names are converted to lower-case unless enclosed by double quotes. Therefore: IN TABLE 'Employees' and IN TABLE 'employees' both refer to the table
named employees, while IN TABLE '“Employees”' refers to the table named
Employees.

ROWS BETWEEN n AND m

Used to return only part of the output rows. This can be used to retrieve the results in parts and avoid exceeding the client’s memory limitations.

Note:

• If the size of the output exceeds the client memory, an error is returned.
• If objects are added and/or removed from the view in between two queries of consequent row ranges, an existing object may be returned in both queries or missing from both queries.
• If the number of requested rows is larger than the actual number of rows in the view, the command should succeed and return only the existing rows.
• The row number is zero-based.

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Examples

SHOW TABLES;
SHOW TABLES LIKE 'my%';
SHOW COLUMNS IN TABLE "my_table";
SHOW COLUMNS LIKE '%product%' IN TABLE "my_table";
SHOW TABLES LIKE '%my' ROWS BETWEEN 100 AND 150;