IBM Db2

You can add Db2 databases as sources to Dremio.

See IBM Db2 Data Types for information about mapping to Dremio data types.

Limitations

Only IBM Db2 for Linux, UNIX, and Windows is supported.

Configuring IBM Db2 as a Source

1. On the Datasets page, to the right of Sources in the left panel, click .
2. In the Add Data Source dialog, under Databases, select IBM Db2.

General Options

1. In the Name field, specify the name by which you want the Db2 source to appear in the Databases section. The name cannot include the following special characters: /, :, [, or ].

2. Under Connection, follow these steps:

   1. In the Host field, specify the hostname or IP address of the database to connect to.
   2. In the Port field, specify the port to use when connecting. The default is 50000.
   3. In the Database field, specify the name of the database.

3. Under Authentication, follow these steps:

   • For Username, enter your database username.
   • For Password, enter your database password.
   note

   Sources containing a large number of files or tables may take longer to be added. During this time, the source name is grayed out and shows a spinner icon, indicating the source is being added. Once complete, the source becomes accessible.

Advanced Options

On the Advanced Options page, you can set values for these non-required options:

Option	Description
Record fetch size	Number of records to fetch at once. Set to 0 (zero) to have Dremio automatically decide. By default, this is set to 200.
Maximum Idle Connections	The total number of connections allowed to be idle at a given time. The default number of maximum idle connections is 8.
Connection Idle Time	The amount of time (in seconds) allowed for a connection to remain idle before the connection is terminated. The default connection idle time is 60 seconds.
Query Timeout	The amount of time (in seconds) allowed to wait for the results of a query. If this time expires, the connection being used is returned to an idle state.
Enable external authorization plugin	When enabled, authorizes an external plugin.
Connection Properties	Connection properties and values for the data source.

Reflection Refresh Options

On the Reflection Refresh page, set the policy that controls how often reflections are scheduled to be refreshed automatically, as well as the time limit after which reflections expire and are removed.

Option	Description
Never refresh	Select to prevent automatic reflection refresh, default is to automatically refresh.
Refresh every	How often to refresh reflections, specified in hours, days or weeks. This option is ignored if Never refresh is selected.
Never expire	Select to prevent reflections from expiring, default is to automatically expire after the time limit below.
Expire after	The time limit after which reflections expire and are removed from Dremio, specified in hours, days or weeks. This option is ignored if Never expire is selected.

Metadata Options

On the Metadata page, you can configure settings to refresh metadata and handle datasets.

Dataset Handling

These are the optional Dataset Handling parameters.

Parameter	Description
Remove dataset definitions if underlying data is unavailable	By default, Dremio removes dataset definitions if underlying data is unavailable. Useful when files are temporarily deleted and added back in the same location with new sets of files.

Metadata Refresh

These are the optional Metadata Refresh parameters:

• Dataset Discovery: The refresh interval for fetching top-level source object names such as databases and tables. Set the time interval using this parameter.

  Parameter	Description
  (Optional) Fetch every	You can choose to set the frequency to fetch object names in minutes, hours, days, or weeks. The default frequency to fetch object names is 1 hour.

• Dataset Details: The metadata that Dremio needs for query planning such as information required for fields, types, shards, statistics, and locality. These are the parameters to fetch the dataset information.

  Parameter	Description
  Fetch mode	You can choose to fetch only from queried datasets that are set by default. Dremio updates details for previously queried objects in a source. Fetching from all datasets is deprecated.
  Fetch every	You can choose to set the frequency to fetch dataset details in minutes, hours, days, or weeks. The default frequency to fetch dataset details is 1 hour.
  Expire after	You can choose to set the expiry time of dataset details in minutes, hours, days, or weeks. The default expiry time of dataset details is 3 hours.

Privileges

On the Privileges tab, you can grant privileges to specific users or roles. See Access Control for additional information about privileges.

note

All privileges are optional.

1. For Privileges, enter the user name or role name that you want to grant access to and click the Add to Privileges button. The added user or role is displayed in the USERS/ROLES table.
2. For the users or roles in the USERS/ROLES table, toggle the checkmark for each privilege you want to grant on the Dremio source that is being created.
3. Click Save after setting the configuration.

Updating an IBM Db2 Source

To update an IBM Db2 source:

1. On the Datasets page, under Databases in the panel on the left, find the name of the source you want to update.
2. Right-click the source name and select Settings from the list of actions. Alternatively, click the source name and then the at the top right corner of the page.
3. In the Source Settings dialog, edit the settings you wish to update. Dremio does not support updating the source name. For information about the settings options, see Configuring IBM Db2 as a Source.
4. Click Save.

Deleting an IBM Db2 Source

note

If the source is in a bad state (for example, Dremio cannot authenticate to the source or the source is otherwise unavailable), only users who belong to the ADMIN role can delete the source.

To delete an IBM Db2 source, perform these steps:

1. On the Datasets page, click Sources > Databases in the panel on the left.

2. In the list of data sources, hover over the name of the source you want to remove and right-click.

3. From the list of actions, click Delete.

4. In the Delete Source dialog, click Delete to confirm that you want to remove the source.

   caution

   Deleting a source causes all downstream views that depend on objects in the source to break.

   note

   Sources containing a large number of files or tables may take longer to be deleted. During this time, the source name is grayed out and shows a spinner icon, indicating the source is being deleted. Once complete, the source disappears.

Predicate Pushdowns

Dremio delegates the execution of these expressions and functions to the database being queried, often dramatically improving query performance. It can also offload entire SQL queries that include one or more of these expressions and functions.

||, AND, OR
=, +, -, /, *
<=, <, >, >=, =, <>, !=
ABS
ADD_MONTHS
AVG
BETWEEN
CASE
CAST
CEIL
CEILING
CHAR_LENGTH
CHARACTER_LENGTH
COALESCE
CONCAT
DATE_ADD
DATE_DIFF
DATE_TRUNC
DATE_TRUNC_CENTURY
DATE_TRUNC_DAY
DATE_TRUNC_DECADE
DATE_TRUNC_HOUR
DATE_TRUNC_MICROSECOND
DATE_TRUNC_MILLENIUM
DATE_TRUNC_MILLISECOND
DATE_TRUNC_MINUTE
DATE_TRUNC_MONTH
DATE_TRUNC_QUARTER
DATE_TRUNC_SECOND
DATE_TRUNC_WEEK
DATE_TRUNC_YEAR
DAYOFMONTH
DAYOFWEEK
DAYOFYEAR
EXTRACT
FLOOR
ILIKE
IN
IS DISTINCT FROM
IS NOT DISTINCT FROM
IS NOT NULL
IS NULL
LAST_DAY
LEFT
LENGTH
LIKE
LOCATE
LOWER
LPAD
LTRIM
MAX
MIN
MOD
NOT
OR
PERCENT_RANK
POSITION
REPLACE
RIGHT
ROUND
RPAD
RTRIM
SIGN
SQRT
STDDEV
STDDEV_POP
STDDEV_SAMP
SUBSTR
SUBSTRING
SUM
TO_CHAR
TO_DATE
TRIM
TRUNC
TRUNCATE
UPPER