Module rdms::robt

Read Only BTree for disk based indexes.

ROBT instances shall have an index file and an optional value-log-file, refer to Config for more information.

Index-file format:

*------------------------------------------* SeekFrom::End(0)
|                marker-length             |
*------------------------------------------* SeekFrom::End(-8)
|                stats-length              |
*------------------------------------------* SeekFrom::End(-16)
|             app-metadata-length          |
*------------------------------------------* SeekFrom::End(-24)
|                  root-fpos               |
*------------------------------------------* SeekFrom::MetaBlock
*                 meta-blocks              *
*                    ...                   *
*------------------------------------------*
*                btree-blocks              *
*                    ...                   *
*                    ...                   *
*------------------------------------------* 0

Tip of the index file contain 32-byte header providing following details:

• Index statistics
• Application metadata
• File-position for btree's root-block.

Total length of metadata-blocks can be computed based on marker-length, stats-length, app-metadata-length.

Structs

Builder	Builder type for constructing Read-Only-BTree index from an iterator.
Config	Configuration options for Read Only BTree.
Iter	Iterate over Robt index, from beginning to end.
Range	Iterate over Robt index, from a lower bound to upper bound.
Reverse	Reverse iterate over Robt index, from an upper bound to lower bound.
Snapshot	A read only snapshot of BTree built using robt index.
Stats	Btree configuration and statistics persisted along with index file.

Enums

MetaItem

Enumerated meta types stored in Robt index.

Functions

read_meta_items

Read meta items from Robt index file.