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    PostgreSQL

    PostgreSQL is an open source object-relational database management system that is known for its reliability and performance.

    Prerequisites

    Ensure that you have the following details before configuring PostgreSQL as a source:

    • Database name
    • Hostname or IP address
    • Port

    Configuring PostgreSQL as a Source

    Perform these steps to configure PostgreSQL:

    1. On the Datasets page, you can see a truncated list of Sources at the bottom-left of the page. Click Add Source.

      This is a screenshot showing how to add a source.

      Alternatively, click Databases. The page displays all database sources. Click the Add database button at the top-right of that page.

    2. In the Add Data Source dialog, click PostgreSQL.

      The following section describes the source configuration tabs.

    General

    The General tab contains the required fields to create a PostgreSQL source.

    This is a screenshot showing the General tab.

    Perform these steps in the General tab:

    1. In the General tab, for Name, enter a name.
    2. For Host, enter the PostgreSQL host name.
    3. For Port, enter the PostgreSQL port number. The default port is 5432.
    4. For Database, enter the PostgreSQL database name.
    5. (Optional) For Encrypt connection, enable encrypted connections to PostgreSQL using SSL. You can modify the encryption validation mode under Advanced Options.
    6. For Authentication, you must choose one of the following authentication options:
    • Master Authentication, this is the default option. Provide the username and password of a master database user with permissions to read required objects:
      • For Username, enter your PostgreSQL database username.
      • For Password, enter your PostgreSQL database password.
    • For Secret Resource Url, provide the username and the Secret Resource URL that allows fetching the credentials, username and password, and the connection details from the AWS Secrets Manager:
      • For Username, enter your PostgreSQL database username.
      • For Secret Resource Url, enter the secret resource URL.

    Advanced Options

    Click Advanced Options in the sidebar.

    This is a screenshot showing the Advanced Options tab.

    note:

    All advanced options are optional.

    Advanced Option Description
    Record fetch size Number of records to fetch at once. Set to 0 (zero) to have Sonar automatically decide. The default record fetch size is 200.
    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.
    Encryption
    Validation Mode    		 When encryption is enabled, set the validation mode as one of the following:
    • Validate certificate and hostname (default mode)
    • Validate certificate only
    • Do not validate certificate or hostname
    Connection Properties Custom key value pairs for the connection relevant to the source. To add a connection property, click Add property and add the property name and value.

    Reflection Refresh

    The Reflection Refresh tab in the sidebar allows you to set time intervals for reflections to refresh or expire.

    This is a screenshot showing the Reflection Refresh tab.

    Metadata

    You can configure settings to refresh metadata and handle datasets. Click Metadata in the sidebar.

    This is a screenshot showing the Metadata tab.

    You can configure Dataset Handling and Metadata Refresh parameters.

    Dataset Handling

    These are the Dataset Handling parameters.

    note:

    All Dataset Handling parameters are optional.

    Parameter Description
    Remove dataset definitions if underlying data is unavailable By default, Sonar 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 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 Sonar needs for query planning such as information required for fields, types, shards, statistics, and locality. These are the parameters to fetch the dataset information.

    note:

    All Dataset Details parameters are optional.

    Parameter Description
    Fetch mode You can choose to fetch only from queried datasets that are set by default. Sonar 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

    You can grant privileges to specific users or roles.

    This is a screenshot showing the Privileges tab.
    1. (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.
    2. (Optional) For the users or roles in the Users table, toggle the green checkmark for each privilege you want to grant to the PostgreSQL source that is being created.

    Click Save after setting the configuration.

    Editing a PostgreSQL Source

    To edit a PostgreSQL source:

    1. On the Datasets page, click Databases. A list of databases is displayed.

    2. Hover over the database and click the Settings This is the icon that represents the Database settings. icon that appears next to the source.

    3. In the Source Settings dialog, you cannot edit the name. Editing other parameters is optional.

    4. Click Save.

    Removing a PostgreSQL Source

    To remove a PostgreSQL source, perform these steps:

    1. On the Datasets page, click Databases. A list of sources is displayed.

    2. Hover over the source and click the More (…) icon that appears next to the source.

    3. From the list of actions, click Remove Source. Confirm that you want to remove the source.

    warning:

    Removing a source causes all downstream views dependent on objects in this source to break.

    Predicate Pushdowns

    Dremio offloads these operations to Postgres.

    *, +, -, /, %
    <, <=, <>, =, >, >=, !=
    AND, NOT, OR, ||
    ABS
    ACOS
    ADD_MONTHS
    ASIN
    ATAN
    ATAN2
    AVG
    CAST
    CBRT
    CEIL
    CEILING
    CHAR_LENGTH
    CHARACTER_LENGTH
    CONCAT
    COS
    COT
    COVAR_POP
    COVAR_SAMP
    DATE_ADD
    DATE_SUB
    DATE_TRUNC_CENTURY
    DATE_TRUNC_DAY
    DATE_TRUNC_DECADE
    DATE_TRUNC_HOUR
    DATE_TRUNC_MINUTE
    DATE_TRUNC_MONTH
    DATE_TRUNC_QUARTER
    DATE_TRUNC_SECOND
    DATE_TRUNC_WEEK
    DATE_TRUNC_YEAR
    DEGREES
    E
    EXP
    EXTRACT_CENTURY
    EXTRACT_DAY
    EXTRACT_DECADE
    EXTRACT_DOW
    EXTRACT_DOY
    EXTRACT_EPOCH
    EXTRACT_HOUR
    EXTRACT_MILLENNIUM
    EXTRACT_MINUTE
    EXTRACT_MONTH
    EXTRACT_QUARTER
    EXTRACT_SECOND
    EXTRACT_WEEK
    EXTRACT_YEAR
    FLOOR
    IS DISTINCT FROM
    IS NOT DISTINCT FROM
    IS NOT NULL
    IS NULL
    LAST_DAY
    LCASE
    LEFT
    LENGTH
    LIKE
    LN
    LOCATE
    LOG
    LOG10
    LOWER
    LPAD
    LTRIM
    MAX
    MEDIAN
    MIN
    MOD
    PERCENT_CONT
    PERCENT_DISC
    PI
    POSITION
    POW
    POWER
    RADIANS
    REGEXP_LIKE
    REPLACE
    REVERSE
    RIGHT
    ROUND
    RPAD
    RTRIM
    SIGN
    SIN
    SQRT
    STDDEV
    STDDEV_POP
    STDDEV_SAMP
    SUBSTR
    SUBSTRING
    SUM
    TAN
    TO_CHAR
    TO_DATE
    TRIM
    TRUNC
    TRUNCATE
    UCASE
    UPPER
    VAR_POP
    VAR_SAMP