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IMPALA-8826: [DOCS] Add docs for PLAN_ROOT_SINK and result spooling

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Change-Id: I78bfceb225d25078c54c1ed8f88ca250ef42dafe
Reviewed-on: http://gerrit.cloudera.org:8080/14314
Reviewed-by: Sahil Takiar <stakiar@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
This commit is contained in:
Alex Rodoni
2019-09-26 16:14:51 -07:00
parent c67e0868e0
commit c4874d9a94
9 changed files with 405 additions and 6 deletions
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7
docs/impala.ditamap
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@@ -194,6 +194,7 @@ under the License.
<topicref href="topics/impala_exec_single_node_rows_threshold.xml"/>
<topicref href="topics/impala_exec_time_limit_s.xml"/>
<topicref href="topics/impala_explain_level.xml"/>
<topicref href="topics/impala_fetch_rows_timeout_ms.xml"/>
<topicref href="topics/impala_hbase_cache_blocks.xml"/>
<topicref href="topics/impala_hbase_caching.xml"/>
<topicref href="topics/impala_idle_session_timeout.xml"/>
@@ -202,9 +203,11 @@ under the License.
<topicref href="topics/impala_live_summary.xml"/>
<topicref href="topics/impala_max_errors.xml"/>
<topicref rev="3.1 IMPALA-6847" href="topics/impala_max_mem_estimate_for_admission.xml"/>
<topicref rev="2.10.0 IMPALA-3200" href="topics/impala_max_row_size.xml"/>
<topicref rev="2.5.0" href="topics/impala_max_num_runtime_filters.xml"/>
<topicref href="topics/impala_max_result_spooling_mem.xml"/>
<topicref rev="2.10.0 IMPALA-3200" href="topics/impala_max_row_size.xml"/>
<topicref href="topics/impala_max_scan_range_length.xml"/>
<topicref href="topics/impala_max_spilled_result_spooling_mem.xml"/>
<topicref href="topics/impala_mem_limit.xml"/>
<topicref rev="2.10.0 IMPALA-3200" href="topics/impala_min_spillable_buffer_size.xml"/>
<topicref rev="2.8.0" href="topics/impala_mt_dop.xml"/>
@@ -240,6 +243,7 @@ under the License.
<!-- This option is for internal use only and might go away without ever being documented. -->
<!-- <topicref href="topics/impala_seq_compression_mode.xml"/> -->
<topicref href="topics/impala_shuffle_distinct_exprs.xml"/>
<topicref href="topics/impala_spool_query_results.xml"/>
<topicref href="topics/impala_support_start_over.xml"/>
<topicref href="topics/impala_sync_ddl.xml"/>
<topicref href="topics/impala_thread_reservation_aggregate_limit.xml"/>
@@ -329,6 +333,7 @@ under the License.
</topicref>
<topicref href="topics/impala_odbc.xml"/>
<topicref href="topics/impala_jdbc.xml"/>
<topicref href="topics/impala_query_results_spooling.xml"/>
</topicref>
<topicref href="topics/impala_troubleshooting.xml">
<topicref href="topics/impala_webui.xml"/>

3
docs/impala_keydefs.ditamap
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@@ -10521,6 +10521,7 @@ under the License.
<keydef href="https://issues.apache.org/jira/browse/IMPALA-9999" scope="external" format="html" keys="IMPALA-9999"/>
<!-- Short form of mapping from Impala release to vendor-specific releases, for use in headings. -->
<keydef keys="impala34"><topicmeta><keywords><keyword>Impala 3.4</keyword></keywords></topicmeta></keydef>
<keydef keys="impala33"><topicmeta><keywords><keyword>Impala 3.3</keyword></keywords></topicmeta></keydef>
<keydef keys="impala32"><topicmeta><keywords><keyword>Impala 3.2</keyword></keywords></topicmeta></keydef>
<keydef keys="impala31"><topicmeta><keywords><keyword>Impala 3.1</keyword></keywords></topicmeta></keydef>
@@ -10585,6 +10586,7 @@ under the License.
<keydef keys="impala132"><topicmeta><keywords><keyword>Impala 1.3.2</keyword></keywords></topicmeta></keydef>
<keydef keys="impala130"><topicmeta><keywords><keyword>Impala 1.3.0</keyword></keywords></topicmeta></keydef>
<keydef keys="impala34_full"><topicmeta><keywords><keyword>Impala 3.4</keyword></keywords></topicmeta></keydef>
<keydef keys="impala33_full"><topicmeta><keywords><keyword>Impala 3.3</keyword></keywords></topicmeta></keydef>
<keydef keys="impala32_full"><topicmeta><keywords><keyword>Impala 3.2</keyword></keywords></topicmeta></keydef>
<keydef keys="impala31_full"><topicmeta><keywords><keyword>Impala 3.1</keyword></keywords></topicmeta></keydef>
@@ -10607,6 +10609,7 @@ under the License.
<keydef keys="impala13_full"><topicmeta><keywords><keyword>Impala 1.3</keyword></keywords></topicmeta></keydef>
<!-- Pointers to changelog pages -->
<keydef keys="changelog_34" href="https://impala.apache.org/docs/changelog-3.4.html" scope="external" format="html"/>
<keydef keys="changelog_33" href="https://impala.apache.org/docs/changelog-3.3.html" scope="external" format="html"/>
<keydef keys="changelog_32" href="https://impala.apache.org/docs/changelog-3.2.html" scope="external" format="html"/>
<keydef keys="changelog_31" href="https://impala.apache.org/docs/changelog-3.1.html" scope="external" format="html"/>

11
docs/shared/ImpalaVariables.xml
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@@ -25,13 +25,13 @@ under the License.
<prodinfo audience="PDF" id="prodinfo_for_html">
<prodname>Impala</prodname>
<vrmlist>
<vrm version="Impala 3.3.x"/>
<vrm version="Impala 3.4.x"/>
</vrmlist>
</prodinfo>
<prodinfo audience="HTML" id="prodinfo_for_pdf">
<prodname></prodname>
<vrmlist>
<vrm version="Impala 3.3.x"/>
<vrm version="Impala 3.4.x"/>
</vrmlist>
</prodinfo>
</metadata>
@@ -42,6 +42,7 @@ under the License.
The docs included with a distro can refer to the distro release number by
editing the values here.
<ul>
<li><ph id="impala34">Impala 3.4</ph></li>
<li><ph id="impala33">Impala 3.3</ph></li>
<li><ph id="impala32">Impala 3.2</ph></li>
<li><ph id="impala31">Impala 3.1</ph></li>
@@ -59,11 +60,11 @@ under the License.
<li><ph id="impala13">Impala 1.3</ph></li>
</ul>
</p>
<p>Release Version Variable - <ph id="ReleaseVersion">Impala 3.3.x</ph></p>
<p>Release Version Variable - <ph id="ReleaseVersion">Impala 3.4.x</ph></p>
<p>Banner for examples showing shell version -<ph id="ShellBanner">(Shell
build version: Impala Shell v3.3.x (<varname>hash</varname>) built on
build version: Impala Shell v3.4.x (<varname>hash</varname>) built on
<varname>date</varname>)</ph></p>
<p>Banner for examples showing impalad version -<ph id="ImpaladBanner">Server version: impalad version 3.3.x (build
<p>Banner for examples showing impalad version -<ph id="ImpaladBanner">Server version: impalad version 3.4.x (build
x.y.z)</ph></p>
<data name="version-message" id="version-message">
<foreign>

3
docs/topics/impala_client.xml
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@@ -21,6 +21,9 @@ under the License.
<concept id="intro_client">
<title>Impala Client Access</title>
<titlealts audience="PDF">
<navtitle>Client Access</navtitle>
</titlealts>
<conbody>

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docs/topics/impala_fetch_rows_timeout_ms.xml Normal file
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@@ -0,0 +1,66 @@
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="FETCH_ROWS_TIMEOUT_MS">
<title>FETCH_ROWS_TIMEOUT_MS Query Option</title>
<titlealts audience="PDF">
<navtitle>FETCH_ROWS_TIMEOUT_MS</navtitle>
</titlealts>
<prolog>
<metadata>
<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"/>
</metadata>
</prolog>
<conbody>
<p>Use the <codeph>FETCH_ROWS_TIMEOUT_MS</codeph> query option to control
how long Impala waits for query results when clients fetch rows.</p>
<p> When this query option is set to <codeph>0</codeph>, fetch requests wait
indefinitely.</p>
<p>The timeout applies both when query result spooling is enabled and disabled:<ul>
<li>When result spooling is disabled (<codeph>SPOOL_QUERY_RESULTS =
FALSE</codeph>), the timeout controls how long a client waits for a
single row batch to be produced by the coordinator. </li>
<li>When result spooling is enabled ( (<codeph>SPOOL_QUERY_RESULTS =
TRUE</codeph>), a client can fetch multiple row batches at a time,
so this timeout controls the total time a client waits for row batches
to be produced.</li>
</ul></p>
<p>The timeout also applies to fetch requests issued against queries in the
'RUNNING' state. A 'RUNNING' query has no rows available, so any fetch
request will wait until the query transitions to the 'FINISHED' state and
for it to fetch all requested rows. A query in the 'FINISHED' state means
that the rows are available to be fetched.</p>
<p><b>Type:</b>
<codeph>INT</codeph></p>
<p><b>Default:</b>
<codeph>10000</codeph> (10 seconds)</p>
<p><b>Added in:</b>
<keyword keyref="impala34"/></p>
<p><b>Related information:</b>
<xref href="impala_max_result_spooling_mem.xml#MAX_RESULT_SPOOLING_MEM"/>,
<xref
href="impala_max_spilled_result_spooling_mem.xml#MAX_SPILLED_RESULT_SPOOLING_MEM"
/>, <xref href="impala_spool_query_results.xml#SPOOL_QUERY_RESULTS"/></p>
</conbody>
</concept>

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docs/topics/impala_max_result_spooling_mem.xml Normal file
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@@ -0,0 +1,59 @@
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="MAX_RESULT_SPOOLING_MEM" rev="2.10.0 IMPALA-3200">
<title>MAX_RESULT_SPOOLING_MEM Query Option</title>
<titlealts audience="PDF">
<navtitle>MAX_RESULT_SPOOLING_MEM</navtitle>
</titlealts>
<prolog>
<metadata>
<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"/>
</metadata>
</prolog>
<conbody>
<p>Use the <codeph>MAX_RESULT_SPOOLING_MEM</codeph> query option to set the
maximum amount of memory used when spooling query results. </p>
<p>If the amount of memory exceeds this value when spooling query results,
all memory will most likely be spilled to disk. </p>
<p>The <codeph>MAX_RESULT_SPOOLING_MEM</codeph> query option is applicable
only when query result spooling is enabled with the
<codeph>SPOOL_QUERY_RESULTS</codeph> query option set to
<codeph>TRUE</codeph>.</p>
<p>Setting the option to <codeph>0</codeph> or <codeph>-1</codeph> means the
memory is unbounded. </p>
<p>You cannot set this query option to values below <codeph>-1</codeph>.</p>
<p><b>Type:</b>
<codeph>INT</codeph></p>
<p><b>Default:</b>
<codeph> 100 * 1024 * 1024 (100 MB)</codeph></p>
<p><b>Added in:</b>
<keyword keyref="impala34"/></p>
<p><b>Related information:</b>
<xref href="impala_fetch_rows_timeout_ms.xml#FETCH_ROWS_TIMEOUT_MS"/>,
<xref
href="impala_max_spilled_result_spooling_mem.xml#MAX_SPILLED_RESULT_SPOOLING_MEM"
/>, <xref href="impala_spool_query_results.xml#SPOOL_QUERY_RESULTS"/></p>
</conbody>
</concept>

63
docs/topics/impala_max_spilled_result_spooling_mem.xml Normal file
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@@ -0,0 +1,63 @@
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="MAX_SPILLED_RESULT_SPOOLING_MEM" rev="2.10.0 IMPALA-3200">
<title>MAX_SPILLED_RESULT_SPOOLING_MEM Query Option</title>
<titlealts audience="PDF">
<navtitle>MAX_SPILLED_RESULT_SPOOLING_MEM</navtitle>
</titlealts>
<prolog>
<metadata>
<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"/>
</metadata>
</prolog>
<conbody>
<p>Use the <codeph>MAX_SPILLED_RESULT_SPOOLING_MEM</codeph> query option to
set the maximum amount of memory that can be spilled when spooling query
results. </p>
<p>If the amount of memory exceeds this value when spooling query results,
the coordinator fragment will block until the client has consumed enough
rows to free up more memory.</p>
<p>The <codeph>MAX_SPILLED_RESULT_SPOOLING_MEM</codeph> query option is
applicable only when query result spooling is enabled with the
<codeph>SPOOL_QUERY_RESULTS</codeph> query option set to
<codeph>TRUE</codeph>. </p>
<p>The value must be greater than or equal to the value of
<codeph>MAX_RESULT_SPOOLING_MEM</codeph>.</p>
<p>Setting the option to <codeph>0</codeph> or <codeph>-1</codeph> means the
memory is unbounded. </p>
<p>Values below <codeph>-1</codeph> are not allowed for this query
option.</p>
<p><b>Type:</b>
<codeph>INT</codeph></p>
<p><b>Default:</b><codeph> 1024 * 1024 * 1024 (1 GB)</codeph></p>
<p><b>Added in:</b>
<keyword keyref="impala34"/></p>
<p><b>Related information:</b>
<xref href="impala_fetch_rows_timeout_ms.xml#FETCH_ROWS_TIMEOUT_MS"/>,
<xref
href="impala_max_spilled_result_spooling_mem.xml#MAX_SPILLED_RESULT_SPOOLING_MEM"
/>, <xref href="impala_spool_query_results.xml#SPOOL_QUERY_RESULTS"/></p>
</conbody>
</concept>

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docs/topics/impala_query_results_spooling.xml Normal file
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@@ -0,0 +1,131 @@
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="data_sink">
<title>Spooling Impala Query Results</title>
<conbody>
<p>In Impala, you can control how query results are materialized and
returned to clients, e.g. impala-shell, Hue, JDBC apps.</p>
<ul>
<li>When query result spooling is disabled, 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 continue to
consume the resources until the query is cancelled and unregistered,
potentially tying up resources and causing other queries to wait for an
extended period of time in admission control.<p>Impala would materialize
rows on-demand where rows are created only when the client requests
them.</p></li>
<li>When query result spooling is enabled, result sets of queries are
eagerly fetched and spooled in the spooling location, 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 results.</p></li>
</ul>
<p>Result spooling is turned off by default, but can be enabled via the
<codeph>SPOOL_QUERY_RESULTS</codeph> query option.</p>
<section id="section_av4_hsy_2jb">
<title>Admission Control and Result Spooling</title>
<p>Query results spooling collects and stores query results in memory that
is controlled by admission control. Use the following query options to
calibrate how much memory to use and when to spill to disk.<dl>
<dlentry>
<dt>MAX_RESULT_SPOOLING_MEM</dt>
<dd>
<p>The maximum amount of memory used when spooling query results.
If this value is exceeded when spooling results, all memory will
most likely be spilled to disk. Set to 100 MB by default. </p>
</dd>
</dlentry>
<dlentry>
<dt>MAX_SPILLED_RESULT_SPOOLING_MEM</dt>
<dd>
<p>The maximum amount of memory that can be spilled to disk when
spooling query results. Must be greater than or equal to
<codeph>MAX_RESULT_SPOOLING_MEM</codeph>. If this value is
exceeded, the coordinator fragment will block until the client
has consumed enough rows to free up more memory. Set to 1 GB by
default.</p>
</dd>
</dlentry>
</dl></p>
</section>
<section id="section_oh2_fsy_2jb">
<title>Fetch Timeout</title>
<p>Resources for a query are released when the query completes its
execution. To prevent clients from indefinitely waiting for query
results, use the <codeph>FETCH_ROWS_TIMEOUT_MS</codeph> query option to
set the timeout when clients fetch rows. Timeout applies both when query
result spooling is enabled and disabled:<ul>
<li>When result spooling is disabled (<codeph>SPOOL_QUERY_RESULTS =
FALSE</codeph>), the timeout controls how long a client waits for
a single row batch to be produced by the coordinator. </li>
<li>When result spooling is enabled ( (<codeph>SPOOL_QUERY_RESULTS =
TRUE</codeph>), a client can fetch multiple row batches at a time,
so this timeout controls the total time a client waits for row
batches to be produced.</li>
</ul></p>
</section>
<section id="section_ahm_bsy_2jb">
<title>Explain Plans</title>
<p>Below is the part of the <codeph>EXPLAIN</codeph> plan output for
result spooling.<codeblock>F01:PLAN FRAGMENT [UNPARTITIONED] hosts=1 instances=1
| Per-Host Resources: mem-estimate=4.02MB mem-reservation=4.00MB thread-reservation=1
PLAN-ROOT SINK
| mem-estimate=4.00MB mem-reservation=4.00MB spill-buffer=2.00MB thread-reservation=0</codeblock><ul>
<li>The <codeph>mem-estimate</codeph> for the <codeph>PLAN-ROOT
SINK</codeph> is an estimate of the amount of memory needed to
spool all the rows returned by the query.</li>
<li>The <codeph>mem-reservation</codeph> is the number and size of the
buffers necessary to spool the query results. By default, the read
and write buffers are 2 MB in size each, which is why the default is
4 MB.</li>
</ul></p>
</section>
<section id="section_ovl_ksy_2jb">
<title>PlanRootSink</title>
<p dir="ltr">In Impala, the <codeph>PlanRootSink</codeph> class controls
the passing of batches of rows to the clients and acts as a queue of
rows to be sent to clients.</p>
<p>
<ul>
<li>
<p>When result spooling is disabled, a single batch or rows is sent
to the <codeph>PlanRootSink</codeph>, and then the client must
consume that batch before another one can be sent.</p>
</li>
<li>
<p>When result spooling is enabled, multiple batches of rows can be
sent to the <codeph>PlanRootSink</codeph>, and multiple batches
can be consumed by the client.</p>
</li>
</ul>
</p>
</section>
<section>
<p><b>Related information:</b>
<xref href="impala_max_result_spooling_mem.xml#MAX_RESULT_SPOOLING_MEM"
/>, <xref
href="impala_max_spilled_result_spooling_mem.xml#MAX_SPILLED_RESULT_SPOOLING_MEM"
/>, <xref href="impala_spool_query_results.xml#SPOOL_QUERY_RESULTS"
/></p>
</section>
</conbody>
</concept>

68
docs/topics/impala_spool_query_results.xml Normal file
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@@ -0,0 +1,68 @@
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<!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">
<navtitle>SPOOL_QUERY_RESULTS</navtitle>
</titlealts>
<prolog>
<metadata>
<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"/>
</metadata>
</prolog>
<conbody>
<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
results.</p></li>
</ul></p>
<p><b>Type:</b>
<codeph>INT</codeph></p>
<p><b>Default:</b>
<codeph>FALSE</codeph></p>
<p><b>Added in:</b>
<keyword keyref="impala34"/></p>
<p><b>Related information:</b>
<xref
href="impala_default_spillable_buffer_size.xml#default_spillable_buffer_size"
/>, <xref
href="impala_max_spilled_result_spooling_mem.xml#MAX_SPILLED_RESULT_SPOOLING_MEM"
/>, <xref
href="impala_max_result_spooling_mem.xml#MAX_RESULT_SPOOLING_MEM"/></p>
</conbody>
</concept>