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| <h1 class="title topictitle1" id="ariaid-title1">NUM_SCANNER_THREADS Query Option</h1> |
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| Maximum number of scanner threads (on each node) used for each query. By default, Impala uses as many cores |
| as are available (one thread per core). You might lower this value if queries are using excessive resources |
| on a busy cluster. Impala imposes a maximum value automatically, so a high value has no practical effect. |
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| Has no effect if multi-threaded query execution is enabled, i.e. |
| <code class="ph codeph">MT_DOP</code> is greater than 0. |
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| <strong class="ph b">Type:</strong> numeric |
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| <strong class="ph b">Default:</strong> 0 |
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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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