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| <h1 class="title topictitle1" id="ariaid-title1">BUFFER_POOL_LIMIT Query Option</h1> |
| |
| |
| |
| |
| <div class="body conbody"> |
| |
| <p class="p"> |
| |
| Defines a limit on the amount of memory that a query can allocate from the |
| internal buffer pool. The value for this limit applies to the memory on each host, |
| not the aggregate memory across the cluster. Typically not changed by users, except |
| during diagnosis of out-of-memory errors during queries. |
| </p> |
| |
| |
| <p class="p"> |
| <strong class="ph b">Type:</strong> integer |
| </p> |
| |
| |
| |
| |
| <p class="p"> |
| <strong class="ph b">Default:</strong> |
| </p> |
| |
| <p class="p"> |
| The default setting for this option is the lower of 80% of the |
| <code class="ph codeph">MEM_LIMIT</code> setting, or the <code class="ph codeph">MEM_LIMIT</code> |
| setting minus 100 MB. |
| </p> |
| |
| |
| <p class="p"> |
| <strong class="ph b">Added in:</strong> <span class="keyword">Impala 2.10.0</span> |
| </p> |
| |
| |
| <p class="p"> |
| <strong class="ph b">Usage notes:</strong> |
| </p> |
| |
| <p class="p"> |
| If queries encounter out-of-memory errors, consider decreasing the |
| <code class="ph codeph">BUFFER_POOL_LIMIT</code> setting to less than 80% of the |
| <code class="ph codeph">MEM_LIMIT setting</code>. |
| </p> |
| |
| |
| <p class="p"> |
| <strong class="ph b">Examples:</strong> |
| </p> |
| |
| |
| <pre class="pre codeblock"><code> |
| -- Set an absolute value. |
| set buffer_pool_limit=8GB; |
| |
| -- Set a relative value based on the MEM_LIMIT setting. |
| set buffer_pool_limit=80%; |
| |
| </code></pre> |
| |
| <p class="p"> |
| <strong class="ph b">Related information:</strong> |
| </p> |
| |
| <p class="p"> |
| <a class="xref" href="impala_default_spillable_buffer_size.html">DEFAULT_SPILLABLE_BUFFER_SIZE Query Option</a>, |
| <a class="xref" href="impala_max_row_size.html">MAX_ROW_SIZE Query Option</a>, |
| <a class="xref" href="impala_min_spillable_buffer_size.html">MIN_SPILLABLE_BUFFER_SIZE Query Option</a>, |
| <a class="xref" href="impala_scalability.html">Scalability Considerations for Impala</a> |
| </p> |
| |
| |
| </div> |
| |
| <div class="related-links"> |
| <div class="familylinks"> |
| <div class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_set.html">SET Statement</a></div> |
| </div> |
| </div></body> |
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