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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="SPOOL_QUERY_RESULTS" rev="2.10.0 IMPALA-3200">
<title>SPOOL_QUERY_RESULTS Query Option</title>
<titlealts audience="PDF">
<data name="Category" value="Impala"/>
<data name="Category" value="Impala Query Options"/>
<data name="Category" value="Querying"/>
<data name="Category" value="Developers"/>
<data name="Category" value="Data Analysts"/>
<p>Use the <codeph>SPOOL_QUERY_RESULTS</codeph> query option to enable query
result spooling, which is disabled by default.</p>
<p>Query result spooling controls how rows are returned to the client. <ul>
<li>When query result spooling is disabled (<codeph>SPOOL_QUERY_RESULTS
= FALSE</codeph>), Impala relies on clients to fetch results to
trigger the generation of more result row batches until all the result
rows have been produced. If a client issues a query without fetching
all the results, the query fragments will continue to consume the
resources until the query is cancelled and unregistered, potentially
tying up resources and cause other queries to wait for extended period
of time in admission control.</li>
<li>When query result spooling is enabled (<codeph>SPOOL_QUERY_RESULTS =
TRUE</codeph>), the result sets of queries are eagerly fetched and
spooled, either in memory or on disk. <p>Once all result rows have
been fetched and stored in the spooling location, the resources are
freed up. Incoming client fetches can get the data from the spooled
<p><b>Added in:</b>
<keyword keyref="impala34"/></p>
<p><b>Related information:</b>
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