Storr Data Models

Overview

This vignette describes the Content-Addressable Storage (CAS) data model used by the storr.tiledb driver. The driver stores storr data inside a TileDB Group that contains two Sparse Arrays:

• tbl_keys maps key-namespace pairs to hashes and optional key metadata
• tbl_data maps content hashes to serialized object values

The arrays are stored as members inside a TileDB Group at the driver’s URI. The Group also contains metadata about the storage format.

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CAS: Group Structure

Members

1. tbl_keys (array) maps key/namespace pairs to hashes and can store expiry and notes.
2. tbl_data (array) maps content hashes to serialized R objects.

Metadata

• hash_algo - name of the hash algorithm used (e.g., "sha256").
• type - group identifier string "storr".
• serial_format - name of the serialization format used (e.g., "rds").

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Array data models

tbl_keys array

A 2-dimensional sparse array that maps key-namespace pairs to hashes and key-metadata.

Dimensions

• namespace (ASCII)
• key (ASCII)

Attributes

• hash (ASCII)
• expires_at (DATETIME_MS)
• notes (UTF8)

tbl_data array

A 1-dimensional sparse array that maps content hashes to serialized values.

Dimensions

• hash (ASCII)

Attributes

• value (ASCII)

TileDB datatypes shown in parentheses.

Example

Below is a short example that shows creating a TileDB-backed driver and inspecting its layout.

# Create a temporary URI
uri <- tempfile()

# Create a driver (initializes the TileDB Group and member arrays)
dr <- driver_tiledb(uri, init = TRUE)

Inspecting the driver directory tree:

dr$dir_tree()

# C:/Users/cgiac/AppData/Local/Temp/RtmpCGgG9I/filea8c4634c2198
# ├── tbl_data
# │   ├── __commits
# │   ├── __fragments
# │   ├── __fragment_meta
# │   ├── __labels
# │   ├── __meta
# │   └── __schema
# │       ├── __1788419331967_1788419331967_74b1721886a26ec2193126881f9dbb8c
# │       └── __enumerations
# ├── tbl_keys
# │   ├── __commits
# │   ├── __fragments
# │   ├── __fragment_meta
# │   ├── __labels
# │   ├── __meta
# │   └── __schema
# │       ├── __1788419331966_1788419331966_0e09559a95f4ec77500deec0c06f103e
# │       └── __enumerations
# ├── __group
# │   └── __1788419332028_1788419332028_1f56eaee7d9f55ceb8eb3340202782d9_2
# ├── __meta
# │   └── __1788419331971_1788419331971_5c4223e71cb4e86ec491b1ad188091ae
# └── __tiledb_group.tdb
# 
# ❯ directories (7) • total size (667 B)