Connecting to Your Data
Dremio supports a variety of data sources, including data as code, metastores, local and cloud-based object storage, and databases.
Nessie catalogs enable you to process, manage, consume, and share data in the same way that code is shared during software development. That is, you are empowered to take control of your data using concepts including version control, commits, and testing and development in isolation from your production data.
- Nessie Catalogs (Preview)
- Amazon Redshift
- Apache Druid
- Dremio Cluster (you can connect to one or more other Dremio Software clusters and run queries on the data sources to which they are connected, and you can run queries that federate data across connected clusters)
- Azure Synapse Analytics
- IBM Db2
- Microsoft Azure Data Explorer
- Microsoft Azure Synapse Analytics
- Microsoft SQL Server
Dremio enables users to run external queries, queries that use the native syntax of the relational database, to process SQL statements that are not yet supported by Dremio or are too complex to convert. Dremio administrators enable the feature for each data source and specify which Dremio users can edit that source. See Querying External Data Sources for more information.
Dremio improves query performance for relational database datasets with Runtime Filtering, which applies dimension table filters to joined fact tables at runtime.
- Decimal Support: Decimal-to-decimal mappings are supported for relational database sources.
- Collation: Relational database sources must have a collation equivalent to
LATIN1_GENERAL_BIN2to ensure consistent results when operations are pushed down. For non-equivalent collations, create a view that coerces the collation to one that is equivalent to
LATIN1_GENERAL_BIN2and access that view.
- For all sources, case-sensitive source data file/table names are not supported. In Dremio, case is ignored in the names of data files.
FILE1.parquetare considered to be equivalent names. Therefore, searching on one of these names can result in unanticipated results.
In addition, columns in a table that have the same name with different cases are not supported. For example, if two columns named
trip_pickup_datetimeexist in the same table, one of the columns may disappear when the header is extracted.
Files and Directories
- note Case-sensitive source data file/table names are not supported. In Dremio, data filenames in your data source are "seen" in a case-insensitive manner. So, if you have three file names with difference cases (for example, `JOE` `Joe`, and `joe`), Dremio "sees" the files as having the same name. Thus, searching on `Joe`, `JOE`, or `joe`, can result in unanticipated data results.
In addition, columns in a table that have the same name with different cases are not supported. For example, if two columns named `Trip_Pickup_DateTime` and `trip_pickup_datetime` exist in the same table, one of the columns may disappear when the header is extracted.