From 72231250ed81e10d66bfe70701e64fa5fe50f712 Mon Sep 17 00:00:00 2001 From: Jon Bratseth Date: Wed, 15 Jun 2016 23:09:44 +0200 Subject: Publish --- streamingvisitors/doc/SearchVisitorProtocol.html | 93 ++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 streamingvisitors/doc/SearchVisitorProtocol.html (limited to 'streamingvisitors/doc/SearchVisitorProtocol.html') diff --git a/streamingvisitors/doc/SearchVisitorProtocol.html b/streamingvisitors/doc/SearchVisitorProtocol.html new file mode 100644 index 00000000000..55100929ac9 --- /dev/null +++ b/streamingvisitors/doc/SearchVisitorProtocol.html @@ -0,0 +1,93 @@ + + + + + + + + + + + + + + + + +

SearchVisitor design

The SearchVisitor is a visitor plugin running in the storaged +binary. It processes queries and docsum requests and returns +SearchResult and DocumentSummary objects to the client. It uses Vespa +Streaming Matcher (VSM) to generate the search results and document +summaries.

Since the distributors in VDS do not have fdispatch capability, +that is implemented in the QRS(client). It must collect all messages +received, merge them and present them to its liking.

Initiation

The client sends down a createVisitor command with the following +parameters set:

Timeout : This is the query timeout.

VisitorLibrary: "SearchVisitor". Tells the framework to +use the SearchVisitor visitor plugin, rather than the default +DumpVisitor.

VisitorParameters: Containing the following arguments for the +SearchVisitor:

"query": The raw encoded query stack from QRS. It + has the same format as the query parameter in the QueryPacket sent + to indexed search.
+
"searchcluster": This identifies which + searchcluster is queried. The visitor uses this to choose the + correct config.
+
"summaryclass": Which summaryclass is wanted.
+
"summarycount": The number of summaries wanted.
+
"aggregation": The aggregation specification as specified + by the fs4 protocol. The aggregation options are the same as for + indexed search. +
+
"sort": The sort specification as specified by the fs4 + protocol.
+
"unique": The field to do duplicate removal on. +
+
"rankprofile": Which rank profile to use. The default is 0.
+
"rankproperties": A set of properties to use in ranking for the backend.
+

The backend will return all hits, but only the requested number of +summaries. It is the client's responsibility to handle "hits" +and "offset" query parameters.

Only singlephase has been implemented as all the data are +available anyway.

"aggregate", "sort" and "unique" are not limited to +attributes as they are in indexed search. Every field has attribute +semantics in streamed search.

SearchResult

This is the message returned to the client after the search has +been conducted.

It contains a list of Hits each containing the documentid as known +by VDS, and a rank identifying the relevance of the document with +respect to the query. The list is sorted on descending rank.

DocumentSummary

This is the message returned to the client after all the document +summaries have been generated.

It contains a list of Summary objects, each containing the +documentId as known by VDS and the summary blob. The list is sorted +on ascending docid. The summary blob is encoded as specified by the +fastserver4 protocol.

AggregationResult

This is the message returned containing the aggregation data. They +follow the format of the aggregation packet used in the fs4 protocol.

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