Feature/view store compression properties

3.7/aql/operations-search.md

@@ -305,6 +305,12 @@ The `SEARCH` operation accepts an options object with the following attributes:
 
 - `collections` (array, _optional_): array of strings with collection names to
  restrict the search to certain source collections
+- `conditionOptimization` (string, _optional_): controls how search criteria
+ get optimized. Possible values:
+ - `"auto"` (default): convert conditions to disjunctive normal form (DNF) and
+ apply optimizations. Removes redundant or overlapping conditions, but can
+ take quite some time even for a low number of nested conditions.
+ - `"none"`: search the index without optimizing the conditions.
 
 **Examples**
 

3.7/arangosearch-views.md

@@ -221,6 +221,9 @@ Note that the `primarySort` option is immutable: it can not be changed after
 View creation. It is therefore not possible to configure it through the Web UI.
 The View needs to be created via the HTTP or JavaScript API (arangosh) to set it.
 
+The primary sort data is LZ4 compressed by default (`primarySortCompression` is
+`"lz4"`). Set it to `"none"` on View creation to trade space for speed.
+
 View Definition/Modification
 ----------------------------
 
@@ -245,7 +248,7 @@ During view modification the following directives apply:
 ### Link Properties
 
 - **analyzers** (_optional_; type: `array`; subtype: `string`; default: `[
- 'identity' ]`)
+ "identity" ]`)
 
  A list of Analyzers, by name as defined via the [Analyzers](arangosearch-analyzers.html),
  that should be applied to values of processed document attributes.
@@ -271,11 +274,11 @@ During view modification the following directives apply:
 - **trackListPositions** (_optional_; type: `boolean`; default: `false`)
 
  If set to `true`, then for array values track the value position in arrays.
- E.g., when querying for the input `{ attr: [ 'valueX', 'valueY', 'valueZ' ]
- }`, the user must specify: `doc.attr[1] == 'valueY'`. Otherwise, all values in
+ E.g., when querying for the input `{ attr: [ "valueX", "valueY", "valueZ" ] }`,
+ the user must specify: `doc.attr[1] == "valueY"`. Otherwise, all values in
  an array are treated as equal alternatives. E.g., when querying for the input
- `{ attr: [ 'valueX', 'valueY', 'valueZ' ] }`, the user must specify: `doc.attr
- == 'valueY'`.
+ `{ attr: [ "valueX", "valueY", "valueZ" ] }`, the user must specify:
+ `doc.attr == "valueY"`.
 
 - **storeValues** (_optional_; type: `string`; default: `"none"`)
 
@@ -294,7 +297,31 @@ During view modification the following directives apply:
  iterates over all documents of a View, wants to sort them by attribute values
  and the (left-most) fields to sort by as well as their sorting direction match
  with the *primarySort* definition, then the `SORT` operation is optimized away.
- Also see [Primary Sort Order](arangosearch-views.html#primary-sort-order)
+ Also see [Primary Sort Order](#primary-sort-order)
+
+- **primarySortCompression** (_optional_; type: `string`; default: `lz4`; _immutable_)
+
+ Defines how to compress the primary sort data (introduced in v3.7.0).
+ ArangoDB v3.5 and v3.6 always compress the index using LZ4.
+
+ - `"lz4"` (default): use LZ4 fast compression.
+ - `"none"`: disable compression to trade space for speed.
+
+- **storedValues** (_optional_; type: `array`; default: `[]`; _immutable_)
+
+ An array of objects to describe which document attributes to store in the
+ View index. It can then cover search queries, which means the data can be
+ taken from the index directly and accessing the storage engine can be avoided.
+
+ Each object is expected in the form
+ `{ field: [ "attr1", "attr2", ... "attrN" ], compression: "none" }`,
+ where the required `field` attribute is an array of strings with one or more
+ document attribute paths. The specified attributes are placed into a single
+ column of the index. A column with all fields that are involved in common
+ search queries is ideal for performance. The column should not include too
+ many unneeded fields however. The optional `compression` attribute defines
+ the compression type used for the internal column-store, which can be `"lz4"`
+ (LZ4 fast compression, default) or `"none"` (no compression).
 
 An inverted index is the heart of ArangoSearch Views.
 The index consists of several independent segments and the index **segment**

3.7/release-notes-new-features37.md

@@ -30,6 +30,77 @@ FOR doc IN viewName
 
 See [ArangoSearch functions](aql/functions-arangosearch.html#like)
 
+### Covering Indexes
+
+It is possible to directly store the values of document attributes in View
+indexes now via a new View property `storedValues` (not to be confused with
+the existing `storeValues`).
+
+View indexes may fully cover `SEARCH` queries for improved performance.
+While late document materialization reduces the amount of fetched documents,
+this new optimization can avoid to access the storage engine entirely.
+
+```json
+{
+ "links": {
+ "articles": {
+ "fields": {
+ "categories": {}
+ }
+ }
+ },
+ "primarySort": [
+ { "field": "publishedAt", "direction": "desc" }
+ ],
+ "storedValues": [
+ { "field": [ "title", "categories" ] }
+ ],
+ ...
+}
+```
+
+In above View definition, the document attribute *categories* is indexed for
+searching, *publishedAt* is used as primary sort order and *title* as well as
+*categories* are stored in the View using the new `storedValues` property.
+
+```js
+FOR doc IN articlesView
+ SEARCH doc.categories == "recipes"
+ SORT doc.publishedAt DESC
+ RETURN {
+ title: doc.title,
+ date: doc.publishedAt,
+ tags: doc.categories
+ }
+```
+
+The query searches for articles which contain a certain tag in the *categories*
+array and returns title, date and tags. All three values are stored in the View
+(`publishedAt` via `primarySort` and the two other via `storedValues`), thus
+no documents need to be fetched from the storage engine to answer the query.
+This is shown in the execution plan as a comment to the *EnumerateViewNode*:
+`/* view query without materialization */`
+
+```js
+Execution plan:
+ Id NodeType Est. Comment
+ 1 SingletonNode 1 * ROOT
+ 2 EnumerateViewNode 1 - FOR doc IN articlesView SEARCH (doc.`categories` == "recipes") SORT doc.`publishedAt` DESC LET #1 = doc.`publishedAt` LET #7 = doc.`categories` LET #5 = doc.`title` /* view query without materialization */
+ 5 CalculationNode 1 - LET #3 = { "title" : #5, "date" : #1, "tags" : #7 } /* simple expression */
+ 6 ReturnNode 1 - RETURN #3
+
+Indexes used:
+ none
+
+Optimization rules applied:
+ Id RuleName
+ 1 move-calculations-up
+ 2 move-calculations-up-2
+ 3 handle-arangosearch-views
+```
+
+See [ArangoSearch Views](arangosearch-views.html#view-properties).
+
 ### Stemming support for more languages
 
 The Snowball library was updated to the latest version 2, adding stemming
@@ -71,6 +142,49 @@ db._query(`RETURN TOKENS("αυτοκινητουσ πρωταγωνιστούσ
 
 Also see [Analyzers: Supported Languages](arangosearch-analyzers.html#supported-languages)
 
+### Condition Optimization Option
+
+The `SEARCH` operation in AQL accepts a new option `conditionOptimization` to
+give users control over the search criteria optimization:
+
+```js
+FOR doc IN myView
+ SEARCH doc.val > 10 AND doc.val > 5 /* more conditions */
+ OPTIONS { conditionOptimization: "none" }
+ RETURN doc
+```
+
+By default, all conditions get converted into disjunctive normal form (DNF).
+Numerous optimizations can be applied, like removing redundant or overlapping
+conditions (such as `doc.val > 10` which is included by `doc.val > 5`).
+However, converting to DNF and optimizing the conditions can take quite some
+time even for a low number of nested conditions which produce dozens of
+conjunctions / disjunctions. It can be faster to just search the index without
+optimizations.
+
+See [SEARCH operation](operations-search.html#search-options).
+
+### Primary Sort Compression Option
+
+There is a new option `primarySortCompression` which can be set on View
+creation to disable the compression of the primary sort data:
+
+```json
+{
+ "primarySort": [
+ { "field": "date", "direction": "desc" },
+ { "field": "title", "direction": "asc" }
+ ],
+ "primarySortCompression": "none",
+ ...
+}
+```
+
+It defaults to LZ4 compression (`"lz4"`), which was already used in ArangoDB
+v3.5 and v3.6.
+
+See [ArangoSearch Views](arangosearch-views.html#view-properties).
+
 SatelliteGraphs
 ---------------