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| <h1 class="title topictitle1" id="ariaid-title1">FETCH_ROWS_TIMEOUT_MS Query Option</h1> |
| |
| |
| |
| <div class="body conbody"> |
| <p class="p">Use the <code class="ph codeph">FETCH_ROWS_TIMEOUT_MS</code> query option to control |
| how long Impala waits for query results when clients fetch rows.</p> |
| |
| <p class="p"> When this query option is set to <code class="ph codeph">0</code>, fetch requests wait |
| indefinitely.</p> |
| |
| <div class="p">The timeout applies both when query result spooling is enabled and disabled:<ul class="ul"> |
| <li class="li">When result spooling is disabled (<code class="ph codeph">SPOOL_QUERY_RESULTS = |
| FALSE</code>), the timeout controls how long a client waits for a |
| single row batch to be produced by the coordinator. </li> |
| |
| <li class="li">When result spooling is enabled ( (<code class="ph codeph">SPOOL_QUERY_RESULTS = |
| TRUE</code>), 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> |
| </div> |
| |
| <p class="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 class="p"><strong class="ph b">Type:</strong> |
| <code class="ph codeph">INT</code></p> |
| |
| <p class="p"><strong class="ph b">Default:</strong> |
| <code class="ph codeph">10000</code> (10 seconds)</p> |
| |
| <p class="p"><strong class="ph b">Added in:</strong> |
| <span class="keyword">Impala 3.4</span></p> |
| |
| <p class="p"><strong class="ph b">Related information:</strong> |
| <a class="xref" href="impala_max_result_spooling_mem.html#MAX_RESULT_SPOOLING_MEM">MAX_RESULT_SPOOLING_MEM Query Option</a>, |
| <a class="xref" href="impala_max_spilled_result_spooling_mem.html#MAX_SPILLED_RESULT_SPOOLING_MEM">MAX_SPILLED_RESULT_SPOOLING_MEM Query Option</a>, <a class="xref" href="impala_spool_query_results.html#SPOOL_QUERY_RESULTS">SPOOL_QUERY_RESULTS Query Option</a></p> |
| |
| </div> |
| |
| <div class="related-links"> |
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| <div class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_query_options.html">Query Options for the SET Statement</a></div> |
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