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    MySQL

    Dremio Configuration

    Supported Versions

    • MySQL 5.x versions that are 5.5.3 or higher

    General

    Host

    Name Description
    Host MySQL host name.
    Port MySQL port number. Defaults to 3306.

    Authentication

    • No authentication method
    • Master Authentication method (default)
      • Username – MySQL user name
      • Password – MySQL password
    • Enable legacy dialect

    Advanced Options

    • Net write timeout (in seconds): Seconds to wait for data from the server before aborting the connection. Default: 60
    • Record fetch size: Number of records to fetch at once. Set to 0 (zero) to have Dremio automatically decide. Default: 10
    • Maximum idle connections: The total number of connections allowed to be idle at a given time. By default, this is set to 8.
    • Connection idle time (s): The amount of time (in seconds) allowed for a connection to remain idle before the connection is terminated. By default, this is set to 60.
    • 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 legacy dialect

    Reflection Refresh

    • Never refresh – Specifies how often to refresh based on hours, days, weeks, or never.
    • Never expire – Specifies how often to expire based on hours, days, weeks, or never.

    Metadata

    Dataset Handling

    • Remove dataset definitions if underlying data is unavailable (Default).
      If this box is not checked and the underlying files under a folder are removed or the folder/source is not accessible, Dremio does not remove the dataset definitions. This option is useful in cases when files are temporarily deleted and put back in place with new sets of files.

    Metadata Refresh

    • Dataset Discovery – Refresh interval for top-level source object names such as names of DBs and tables.
      • Fetch every – Specify fetch time based on minutes, hours, days, or weeks. Default: 1 hour
    • Dataset Details – The metadata that Dremio needs for query planning such as information needed for fields, types, shards, statistics, and locality.
      • Fetch mode – Specify either Only Queried Datasets, All Datasets, or As Needed. Default: Only Queried Datasets
        • Only Queried Datasets – Dremio updates details for previously queried objects in a source.
          This mode increases query performance because less work is needed at query time for these datasets.
        • All Datasets – Dremio updates details for all datasets in a source. This mode increases query performance because less work is needed at query time.
        • As Needed – Dremio updates details for a dataset at query time. This mode minimized metadata queries on a source when not used, but might lead to longer planning times.
      • Fetch every – Specify fetch time based on minutes, hours, days, or weeks. Default: 1 hour
      • Expire after – Specify expiration time based on minutes, hours, days, or weeks. Default: 3 hours

    Sharing

    You can specify which users can edit. Options include:

    • All users can edit.
    • Specific users can edit.

    Predicate Pushdowns

    Dremio offloads these operations to MySQL.

    *, +, -, /, %
    <, <=, <>, =, >, >=, !=
    AND, NOT, NOT LIKE, OR, ||
    ABS
    ACOS
    ADD_MONTHS
    ASIN
    ATAN
    ATAN2
    AVG
    CAST
    CEIL
    CEILING
    CHAR_LENGTH
    CHARACTER_LENGTH
    CONCAT
    COS
    COT
    CURRENT_DATE
    CURRENT_TIME
    CURRENT_TIMESTAMP
    DATE_ADD
    DATE_SUB
    DATE_TRUNC_DAY
    DATE_TRUNC_DECADE
    DATE_TRUNC_HOUR
    DATE_TRUNC_MINUTE
    DATE_TRUNC_MONTH
    DATE_TRUNC_SECOND
    DATE_TRUNC_WEEK
    DATE_TRUNC_YEAR
    DEGREES
    E
    EXP
    EXTRACT_DAY
    EXTRACT_DOW
    EXTRACT_DOY
    EXTRACT_HOUR
    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
    MIN
    MOD
    PI
    POSITION
    POW
    POWER
    RADIANS
    RAND
    REPLACE
    REVERSE
    RIGHT
    ROUND
    RPAD
    RTRIM
    SIGN
    SIN
    SQRT
    STDDEV
    STDDEV_POP
    STDDEV_SAMP
    SUBSTR
    SUBSTRING
    SUM
    TAN
    TIMESTAMPADD_DAY
    TIMESTAMPADD_HOUR
    TIMESTAMPADD_MINUTE
    TIMESTAMPADD_MONTH
    TIMESTAMPADD_QUARTER
    TIMESTAMPADD_SECOND
    TIMESTAMPADD_YEAR
    TIMESTAMPDIFF_DAY
    TIMESTAMPDIFF_HOUR
    TIMESTAMPDIFF_MINUTE
    TIMESTAMPDIFF_MONTH
    TIMESTAMPDIFF_QUARTER
    TIMESTAMPDIFF_SECOND
    TIMESTAMPDIFF_WEEK
    TIMESTAMPDIFF_YEAR
    TO_DATE
    TRIM
    TRUNC
    TRUNCATE
    UCASE
    UPPER
    VAR_POP
    VAR_SAMP

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