19.4. Partition Schemes

Partition schemes define how data is stored on the filesystem. The scheme is important because it determines how the data is queried. When evaluating a query filter, the partition scheme is leveraged to prune data files that do not match the filter. There are three main types of partition schemes provided: spatial, temporal and attribute.

The partition scheme must be provided when creating a schema. The scheme is defined by a well-known name and a map of configuration options. See Configuring the Partition Scheme for details on how to specify a partition scheme.

19.4.1. Composite Schemes

Composite schemes are hierarchical combinations of other schemes. A composite scheme is named by concatenating the names of the constituent schemes, separated with commas, e.g. hourly,z2-2bits. The configuration options for each child scheme should be merged into a single configuration for the composite scheme.

19.4.2. Temporal Schemes

Temporal schemes lay out data based on a Java DateTime format string, separated by forward slashes, which is used to build a directory structure. All temporal schemes support the following common configuration option:

  • dtg-attribute - The name of a Date-type attribute from the SimpleFeatureType to use for partitioning data. If not specified, the default date attribute is used.

19.4.2.1. Date-Time Scheme

Name: datetime

Configuration:

  • datetime-format - A Java DateTime format string, separated by forward slashes, which will be used to build a directory structure. For example, yyyy/MM/dd.
  • step-unit - A java.time.temporal.ChronoUnit defining how to increment the leaf of the partition scheme
  • step - The amount to increment the leaf of the partition scheme. If not specified, defaults to 1

The date-time scheme provides a fully customizable temporal scheme.

19.4.2.2. Hourly Scheme

Name: hourly

The hourly scheme partitions data by the hour, using the layout yyyy/MM/dd/HH.

19.4.2.3. Minute Scheme

Name: minute

The minute scheme partitions data by the minute, using the layout yyyy/MM/dd/HH/mm.

19.4.2.4. Daily Scheme

Name: daily

The daily scheme partitions data by the day, using the layout yyyy/MM/dd.

19.4.2.5. Weekly Scheme

Name: weekly

The weekly scheme partitions data by the week, using the layout yyyy/ww.

19.4.2.6. Monthly Scheme

Name: monthly

The monthly scheme partitions data by the month, using the layout yyyy/MM.

19.4.2.7. Julian Schemes

Names: julian-minute, julian-hourly, julian-daily

Julian schemes partition data by Julian day, instead of month/day. They use the patterns yyyy/DDD/HH/mm, yyyy/DDD/HH, and yyyy/DDD respectively

19.4.3. Spatial Schemes

Spatial schemes lay out data based on a space-filling curve. All spatial schemes support the following common configuration option:

  • geom-attribute - The name of a Geometry-type attribute from the SimpleFeatureType to use for partitioning data. If not specified, the default geometry is used.

19.4.3.1. Z2 Scheme

Name: z2

Configuration:

  • z2-resolution - The number of bits of precision to use for z indexing. Must be a power of 2.

The Z2 scheme uses a Z2 space-filling curve, and can only be used with Point-type geometries. Instead of specifying the resolution as a configuration option, it may be specified in the name, as z2-<n>bits, where <n> is replaced with the Z2 resolution, e.g. z2-2bits.

19.4.3.2. XZ2 Scheme

Name: xz2

Configuration:

  • xz2-resolution - The number of bits of precision to use for z indexing. Must be a power of 2.

The XZ2 scheme uses an XZ2 space-filling curve, and can be used with any geometry type. Instead of specifying the resolution as a configuration option, it may be specified in the name, as xz2-<n>bits, where <n> is replaced with the XZ2 resolution, e.g. xz2-2bits.

19.4.4. Attribute Schemes

Attribute schemes lay out data based on a lexicoded attribute value.

Name: attribute

Configuration:

  • partitioned-attribute - The name of an attribute from the SimpleFeatureType to use for partitioning data.