Difference between revisions of "Storage Layout"
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==Data Types== | ==Data Types== | ||
* {{Type|Num}}: compressed integer (1-5 bytes) | * {{Type|Num}}: compressed integer (1-5 bytes) | ||
| − | * {{Type|Token}}: length ( | + | * {{Type|Token}}: length ({{Type|Num}}) and bytes of UTF8 byte representation |
| − | * {{Type| | + | * {{Type|Double}}: number, stored as token |
| − | * {{Type| | + | * {{Type|Boolean}}: boolean (1 byte, <code>00</code> or <code>01</code>) |
* {{Type|TokenSet}}: key array (<code>Tokens</code>), next/bucket/size arrays (<code>Nums</code>) | * {{Type|TokenSet}}: key array (<code>Tokens</code>), next/bucket/size arrays (<code>Nums</code>) | ||
| + | * {{Type|Nums}}, {{Type|Tokens}} and {{Type|Doubles}} are arrays of values, and introduced with the number of entries ({{Type|Num}}) | ||
==inf.basex== | ==inf.basex== | ||
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| valign='top' | [https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/data/DiskData.java DiskData()] | | valign='top' | [https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/data/DiskData.java DiskData()] | ||
|- | |- | ||
| − | | valign='top' | '''2.1. Name Index'''<br/> | + | | valign='top' | '''2.1. Name Index'''<br/>Tag/attribute names |
| − | | 1. Token set, storing all names ({{Type|TokenSet}})<br />2. One StatsKey instance per entry:<br/>2.1. Content kind ({{Type|Num}})<br />2.1.1. Number: min/max ({{Type|Doubles}})<br />2.1.2. Category: number of entries ({{Type|Num}}), entries ({{Type|Tokens}})<br />2.2. Number of entries ({{Type|Num}})<br />2.3. Leaf flag ({{Type|Boolean}})<br />2.4. Maximum text length ({{Type|Double}}; legacy, could be {{Type|Num}}) | + | | 1. Token set, storing all names ({{Type|TokenSet}})<br />2. One StatsKey instance per entry:<br/>2.1. Content kind ({{Type|Num}}):<br />2.1.1. Number: min/max ({{Type|Doubles}})<br />2.1.2. Category: number of entries ({{Type|Num}}), entries ({{Type|Tokens}})<br />2.2. Number of entries ({{Type|Num}})<br />2.3. Leaf flag ({{Type|Boolean}})<br />2.4. Maximum text length ({{Type|Double}}; legacy, could be {{Type|Num}}) |
| valign='top' | [https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/index/Names.java Names()]<br/>[https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/util/hash/TokenSet.java TokenSet.read()]<br/>[https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/index/StatsKey.java StatsKey()] | | valign='top' | [https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/index/Names.java Names()]<br/>[https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/util/hash/TokenSet.java TokenSet.read()]<br/>[https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/index/StatsKey.java StatsKey()] | ||
|- | |- | ||
| Line 38: | Line 39: | ||
| 1. Token set, storing prefixes ({{Type|TokenSet}})<br/>2. Token set, storing URIs ({{Type|TokenSet}})<br/>3. NSNode:<br/>3.1. pre value ({{Type|Num}})<br/>3.2. References to prefix/URI pairs ({{Type|Nums}})<br/>3.3. Number of children ({{Type|Num}})<br/>3.4. Recursive generation of child nodes (→ 3) | | 1. Token set, storing prefixes ({{Type|TokenSet}})<br/>2. Token set, storing URIs ({{Type|TokenSet}})<br/>3. NSNode:<br/>3.1. pre value ({{Type|Num}})<br/>3.2. References to prefix/URI pairs ({{Type|Nums}})<br/>3.3. Number of children ({{Type|Num}})<br/>3.4. Recursive generation of child nodes (→ 3) | ||
| valign='top' | [https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/data/Namespaces.java Namespaces()]<br/>[https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/data/NSNode.java NSNode()] | | valign='top' | [https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/data/Namespaces.java Namespaces()]<br/>[https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/data/NSNode.java NSNode()] | ||
| + | |- | ||
| + | | valign='top' | '''2.4. Document Index''' | ||
| + | | Array of integers, representing the distances between all document pre values ({{Type|Nums}}) | ||
| + | | valign='top' | [https://github.com/BaseXdb/basex/blob/master/src/main/java/org/basex/index/DocIndex.java DocIndex()] | ||
|} | |} | ||
Revision as of 18:51, 26 October 2011
Version: 7.0
Data Types
Num: compressed integer (1-5 bytes)Token: length (Num) and bytes of UTF8 byte representationDouble: number, stored as tokenBoolean: boolean (1 byte,00or01)TokenSet: key array (Tokens), next/bucket/size arrays (Nums)Nums,TokensandDoublesare arrays of values, and introduced with the number of entries (Num)
inf.basex
| Description | Format | Method |
|---|---|---|
| Disk Data | Database meta information | DiskData() |
| 1. Meta Data | Key/value pairs, suffixed by empty key (Token/Token):• PERM → User Permissions
|
MetaData() Users() |
| 2. Main memory indexes | Key/value pairs, suffixed by empty key (Token/Token):• TAGS → Tag Index• ATTS → Attribute Index• PATH → Path Index• NS → Namespaces• DOCS → Document Index
|
DiskData() |
| 2.1. Name Index Tag/attribute names |
1. Token set, storing all names (TokenSet)2. One StatsKey instance per entry: 2.1. Content kind ( Num):2.1.1. Number: min/max ( Doubles)2.1.2. Category: number of entries ( Num), entries (Tokens)2.2. Number of entries ( Num)2.3. Leaf flag ( Boolean)2.4. 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 discarded2.6. 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() |
| 2.4. Document Index | Array of integers, representing the distances between all document pre values (Nums)
|
DocIndex() |
