283 lines
9.0 KiB
Plaintext
283 lines
9.0 KiB
Plaintext
[role="xpack"]
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[testenv="basic"]
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[[sql-rest]]
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== SQL REST API
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The SQL REST API accepts SQL in a JSON document, executes it,
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and returns the results.
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For example:
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[source,js]
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--------------------------------------------------
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POST /_sql?format=txt
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{
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"query": "SELECT * FROM library ORDER BY page_count DESC LIMIT 5"
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[setup:library]
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Which returns:
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[source,text]
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--------------------------------------------------
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author | name | page_count | release_date
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-----------------+--------------------+---------------+------------------------
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Peter F. Hamilton|Pandora's Star |768 |2004-03-02T00:00:00.000Z
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Vernor Vinge |A Fire Upon the Deep|613 |1992-06-01T00:00:00.000Z
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Frank Herbert |Dune |604 |1965-06-01T00:00:00.000Z
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Alastair Reynolds|Revelation Space |585 |2000-03-15T00:00:00.000Z
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James S.A. Corey |Leviathan Wakes |561 |2011-06-02T00:00:00.000Z
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--------------------------------------------------
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// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/]
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// TESTRESPONSE[_cat]
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[[sql-kibana-console]]
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.Using Kibana Console
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If you are using {kibana-ref}/console-kibana.html[Kibana Console].
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(which is highly recommended), take advantage of the
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triple quotes `"""` when creating the query. This not only automatically escapes double
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quotes (`"`) inside the query string but also support multi-line as shown below:
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image:images/sql/rest/console-triple-quotes.png[]
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[[sql-rest-format]]
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[float]
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=== Response Data Formats
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While the textual format is nice for humans, computers prefer something
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more structured.
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{es-sql} can return the data in the following formats which can be set
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either through the `format` property in the URL or by setting the `Accept` HTTP header:
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NOTE: The URL parameter takes precedence over the `Accept` HTTP header.
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If neither is specified then the response is returned in the same format as the request.
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[cols="^m,^4m,^8"]
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|===
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s|format
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s|`Accept` HTTP header
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s|Description
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3+h| Human Readable
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|csv
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|text/csv
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|https://en.wikipedia.org/wiki/Comma-separated_values[Comma-separated values]
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|json
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|application/json
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|https://www.json.org/[JSON] (JavaScript Object Notation) human-readable format
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|tsv
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|text/tab-separated-values
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|https://en.wikipedia.org/wiki/Tab-separated_values[Tab-separated values]
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|txt
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|text/plain
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|CLI-like representation
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|yaml
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|application/yaml
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|https://en.wikipedia.org/wiki/YAML[YAML] (YAML Ain't Markup Language) human-readable format
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3+h| Binary Formats
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|cbor
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|application/cbor
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|http://cbor.io/[Concise Binary Object Representation]
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|smile
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|application/smile
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|https://en.wikipedia.org/wiki/Smile_(data_interchange_format)[Smile] binary data format similar to CBOR
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|===
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[source,js]
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--------------------------------------------------
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POST /_sql?format=json
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{
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"query": "SELECT * FROM library ORDER BY page_count DESC",
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"fetch_size": 5
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[setup:library]
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Which returns:
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[source,js]
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--------------------------------------------------
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{
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"columns": [
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{"name": "author", "type": "text"},
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{"name": "name", "type": "text"},
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{"name": "page_count", "type": "short"},
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{"name": "release_date", "type": "datetime"}
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],
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"rows": [
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["Peter F. Hamilton", "Pandora's Star", 768, "2004-03-02T00:00:00.000Z"],
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["Vernor Vinge", "A Fire Upon the Deep", 613, "1992-06-01T00:00:00.000Z"],
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["Frank Herbert", "Dune", 604, "1965-06-01T00:00:00.000Z"],
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["Alastair Reynolds", "Revelation Space", 585, "2000-03-15T00:00:00.000Z"],
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["James S.A. Corey", "Leviathan Wakes", 561, "2011-06-02T00:00:00.000Z"]
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],
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"cursor": "sDXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAAEWWWdrRlVfSS1TbDYtcW9lc1FJNmlYdw==:BAFmBmF1dGhvcgFmBG5hbWUBZgpwYWdlX2NvdW50AWYMcmVsZWFzZV9kYXRl+v///w8="
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}
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--------------------------------------------------
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// TESTRESPONSE[s/sDXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAAEWWWdrRlVfSS1TbDYtcW9lc1FJNmlYdw==:BAFmBmF1dGhvcgFmBG5hbWUBZgpwYWdlX2NvdW50AWYMcmVsZWFzZV9kYXRl\+v\/\/\/w8=/$body.cursor/]
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[[sql-pagination]]
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[float]
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=== Paginating through a large response
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Using the example above, onu can continue to the next page by sending back the `cursor` field. In
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case of text format the cursor is returned as `Cursor` http header.
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[source,js]
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--------------------------------------------------
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POST /_sql?format=json
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{
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"cursor": "sDXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAAEWYUpOYklQMHhRUEtld3RsNnFtYU1hQQ==:BAFmBGRhdGUBZgVsaWtlcwFzB21lc3NhZ2UBZgR1c2Vy9f///w8="
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[continued]
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// TEST[s/sDXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAAEWYUpOYklQMHhRUEtld3RsNnFtYU1hQQ==:BAFmBGRhdGUBZgVsaWtlcwFzB21lc3NhZ2UBZgR1c2Vy9f\/\/\/w8=/$body.cursor/]
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Which looks like:
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[source,js]
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--------------------------------------------------
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{
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"rows" : [
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["Dan Simmons", "Hyperion", 482, "1989-05-26T00:00:00.000Z"],
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["Iain M. Banks", "Consider Phlebas", 471, "1987-04-23T00:00:00.000Z"],
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["Neal Stephenson", "Snow Crash", 470, "1992-06-01T00:00:00.000Z"],
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["Frank Herbert", "God Emperor of Dune", 454, "1981-05-28T00:00:00.000Z"],
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["Frank Herbert", "Children of Dune", 408, "1976-04-21T00:00:00.000Z"]
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],
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"cursor" : "sDXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAAEWODRMaXBUaVlRN21iTlRyWHZWYUdrdw==:BAFmBmF1dGhvcgFmBG5hbWUBZgpwYWdlX2NvdW50AWYMcmVsZWFzZV9kYXRl9f///w8="
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}
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--------------------------------------------------
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// TESTRESPONSE[s/sDXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAAEWODRMaXBUaVlRN21iTlRyWHZWYUdrdw==:BAFmBmF1dGhvcgFmBG5hbWUBZgpwYWdlX2NvdW50AWYMcmVsZWFzZV9kYXRl9f\/\/\/w8=/$body.cursor/]
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Note that the `columns` object is only part of the first page.
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You've reached the last page when there is no `cursor` returned
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in the results. Like Elasticsearch's <<search-request-scroll,scroll>>,
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SQL may keep state in Elasticsearch to support the cursor. Unlike
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scroll, receiving the last page is enough to guarantee that the
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Elasticsearch state is cleared.
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To clear the state earlier, you can use the clear cursor command:
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[source,js]
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--------------------------------------------------
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POST /_sql/close
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{
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"cursor": "sDXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAAEWYUpOYklQMHhRUEtld3RsNnFtYU1hQQ==:BAFmBGRhdGUBZgVsaWtlcwFzB21lc3NhZ2UBZgR1c2Vy9f///w8="
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[continued]
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// TEST[s/sDXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAAEWYUpOYklQMHhRUEtld3RsNnFtYU1hQQ==:BAFmBGRhdGUBZgVsaWtlcwFzB21lc3NhZ2UBZgR1c2Vy9f\/\/\/w8=/$body.cursor/]
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Which will like return the
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[source,js]
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--------------------------------------------------
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{
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"succeeded" : true
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}
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--------------------------------------------------
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// TESTRESPONSE
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[[sql-rest-filtering]]
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[float]
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=== Filtering using {es} query DSL
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You can filter the results that SQL will run on using a standard
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{es} query DSL by specifying the query in the filter
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parameter.
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[source,js]
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--------------------------------------------------
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POST /_sql?format=txt
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{
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"query": "SELECT * FROM library ORDER BY page_count DESC",
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"filter": {
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"range": {
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"page_count": {
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"gte" : 100,
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"lte" : 200
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}
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}
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},
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"fetch_size": 5
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[setup:library]
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Which returns:
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[source,text]
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--------------------------------------------------
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author | name | page_count | release_date
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---------------+------------------------------------+---------------+------------------------
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Douglas Adams |The Hitchhiker's Guide to the Galaxy|180 |1979-10-12T00:00:00.000Z
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--------------------------------------------------
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// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/]
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// TESTRESPONSE[_cat]
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[[sql-rest-fields]]
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[float]
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=== Supported REST parameters
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In addition to the `query` and `fetch_size`, a request a number of user-defined fields for specifying
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the request time-outs or localization information (such as timezone).
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The table below lists the supported parameters:
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[cols="^m,^m,^5"]
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|===
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s|name
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s|Default value
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s|Description
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|query
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|Mandatory
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|SQL query to execute
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|fetch_size
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|1000
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|The maximum number of rows (or entries) to return in one response
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|filter
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|none
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|Optional {es} query DSL for additional <<sql-rest-filtering, filtering>>.
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|request_timeout
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|90s
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|The timeout before the request fails.
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|page_timeout
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|45s
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|The timeout before a pagination request fails.
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|time_zone
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|`Z` (or `UTC`)
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|Time-zone in ISO 8601 used for executing the query on the server.
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More information available https://docs.oracle.com/javase/8/docs/api/java/time/ZoneId.html[here].
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|===
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Do note that most parameters (outside the timeout ones) make sense only during the initial query - any follow-up pagination request only requires the `cursor` parameter as explained in the <<sql-pagination, pagination>> chapter.
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That's because the query has already been executed and the calls are simply about returning the found results - thus the parameters are simply ignored. |