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3be0f122a5
These are refugees from doc_prototype. They can be rendered with the DITA Open Toolkit version 2.3.3 by: /tmp/dita-ot-2.3.3/bin/dita \ -i impala.ditamap \ -f html5 \ -o $(mktemp -d) \ -filter impala_html.ditaval Change-Id: I8861e99adc446f659a04463ca78c79200669484f Reviewed-on: http://gerrit.cloudera.org:8080/5014 Reviewed-by: John Russell <jrussell@cloudera.com> Tested-by: John Russell <jrussell@cloudera.com>
50 lines
1.5 KiB
XML
50 lines
1.5 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
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<concept id="prefetch_mode" rev="2.6.0 IMPALA-3286">
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<title>PREFETCH_MODE Query Option (<keyword keyref="impala26"/> or higher only)</title>
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<titlealts audience="PDF"><navtitle>PREFETCH_MODE</navtitle></titlealts>
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<prolog>
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<metadata>
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<data name="Category" value="Impala"/>
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<data name="Category" value="Impala Query Options"/>
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<data name="Category" value="Performance"/>
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<data name="Category" value="Developers"/>
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<data name="Category" value="Data Analysts"/>
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</metadata>
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</prolog>
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<conbody>
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<p rev="2.6.0 IMPALA-3286">
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<indexterm audience="Cloudera">PREFETCH_MODE query option</indexterm>
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Determines whether the prefetching optimization is applied during
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join query processing.
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</p>
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<p>
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<b>Type:</b> numeric (0, 1)
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or corresponding mnemonic strings (<codeph>NONE</codeph>, <codeph>HT_BUCKET</codeph>).
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</p>
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<p>
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<b>Default:</b> 1 (equivalent to <codeph>HT_BUCKET</codeph>)
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</p>
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<p conref="../shared/impala_common.xml#common/added_in_260"/>
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<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
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<p>
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The default mode is 1, which means that hash table buckets are
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prefetched during join query processing.
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</p>
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<p conref="../shared/impala_common.xml#common/related_info"/>
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<p>
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<xref href="impala_joins.xml#joins"/>,
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<xref href="impala_perf_joins.xml#perf_joins"/>.
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</p>
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</conbody>
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</concept>
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