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
- In the bottom-left corner of the Datasets page, click Add Source.
- Under Databases in the Add Data Source dialog, select IBM Db2.
General Options
- In the Name field, specify the name by which you want the Db2 source to appear in the Databases section.
- Under Connection, follow these steps:
- In the Host field, specify the hostname or IP address of the database to connect to.
- In the Port field, specify the port to use when connecting. The default is 50000.
- In the Database field, specify the name of the database.
- Under Authentication, specify the username and password for Dremio to use when connecting to the Db2 source.
Advanced Options
On the Advanced Options page, you can set values for these non-required options:
| Option | Description |
|---|---|
| Maximum Idle Connections | The total number of connections allowed to be idle at a given time. The default 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. |
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 page, you can grant privileges to specific users or roles. See Access Controls for additional information about user privileges.
- (Optional) 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 table.
- (Optional) For the users or roles in the Users table, toggle the green checkmark for each privilege you want to grant on the Dremio source that is being created.
- Click Save after setting the configuration.
Editing an IBM Db2 Source
To edit a Db2 source:
- In the Datasets UI, click External Sources at the bottom-left of the page. A list of sources is displayed.
- Under the Action column, click the Settings (gear) icon for the source you want to edit. From the list of actions, click Edit Details. Alternatively, you can click the source and click the Settings (gear) icon of the source.
- In the Edit Source dialog, you cannot edit the name. Editing other parameters is optional. For parameters and advanced options, see Configuring Db2 as a Source.
- Click Save.
Removing a Db2 Source
To remove a Db2 source, perform these steps:
- In the Datasets UI, click External Sources at the bottom-left of the page. A list of sources is displayed.
- Under the Action column, click the Settings (gear) icon for the source that you want to remove.
- From the list of actions, click Remove Source. Confirm that you want to remove the source.
Removing a source causes all downstream views dependent on objects in this source to break.
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
Running Queries Directly on IBM Db2 Through Dremio
Dremio users can run pass queries through Dremio to run on IBM Db2. Doing so can sometimes decrease query execution times. For more information, see Querying Relational-Database Sources Directly.