Storage Layout

Version: 7.0

Data Types

• Num: compressed integer (1-5 bytes)
• Token: length (Num) and bytes of UTF8 byte representation
• double: number, stored as token
• boolean: boolean (1 byte, 00 or 01)

inf.basex

Description	Format	Method
Disk Data	Database meta information	DiskData()
1. Meta Data	Pairs of key/value tokens, suffixed by empty key: • PERM → User Permissions	MetaData.read() Users.read()
2. Main memory indexes	Pairs of key/value tokens, suffixed by empty key: • TAGS → Tag Index • ATTS → Attribute Index • PATH → Path Index • NS → Namespaces • DOCS → Document Index	DiskData()
2.1. Name Index Element/attribute names	Token set, enriched with statistical information: 1. Token set: key array (Tokens), next/bucket/size arrays (Nums) 2. Content kind (Num) 2.1. Number: min/max (Doubles) 2.2. Category: number of entries (Num), entries (Tokens) 2.3. Number of entries (Num) 2.4. Leaf flag (Boolean) 2.5. Maximum text length (Double; legacy, could be Num)	Names() TokenSet.read() StatsKey()
2.2. Path Index	1. Flag for path definition (Boolean, always true; legacy) 2. PathNode: 2.1. Name reference (Num) 2.2. Node kind (Num) 2.3. Number of occurrences (Num) 2.4. Number of children (Num) 2.5. Double; legacy, can be reused or discarded 2.6. Recursive generation of child nodes (→ 2)	PathSummary() PathNode()
2.3. Namespaces	1. Token set, storing prefixes (TokenSet) 2. Token set, storing URIs (TokenSet) 3. NSNode: 3.1. pre value (Num) 3.2. References to prefix/URI pairs (Nums) 3.3. Number of children (Num) 3.4. Recursive generation of child nodes (→ 3)	Namespaces() NSNode()