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| <!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
| <concept rev="3.2.0" id="resource_trace_ratio"> |
| |
| <title>RESOURCE_TRACE_RATIO Query Option (<keyword keyref="impala32_full"/> or higher only)</title> |
| |
| <titlealts audience="PDF"> |
| |
| <navtitle>RESOURCE_TRACE_RATIO</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> |
| The <codeph>RESOURCE_TRACE_RATIO</codeph> query option specifies the ratio of queries |
| where the CPU usage info will be included in the profiles. Collecting CPU usage and |
| sending it around adds a slight overhead during query execution. This query option lets |
| you control whether to collect additional information to diagnose the resource usage. |
| </p> |
| |
| <p> |
| For example, setting <codeph>RESOURCE_TRACE_RATIO=1</codeph> adds a trace of the CPU usage |
| to the profile of each query. |
| </p> |
| |
| <p> |
| Setting <codeph>RESOURCE_TRACE_RATIO=0.5</codeph> means that randomly selected half of all |
| queries will have that information collected by the coordinator and included in the |
| profiles. |
| </p> |
| |
| <p> |
| Setting <codeph>RESOURCE_TRACE_RATIO=0</codeph> means that CPU usage will not be tracked |
| and included in the profiles. |
| </p> |
| |
| <p> |
| Values from 0 to 1 are allowed. |
| </p> |
| |
| <p> |
| <b>Type:</b> Number |
| </p> |
| |
| <p> |
| <b>Default:</b> 0 |
| </p> |
| |
| <p> |
| <b>Added in:</b> <keyword keyref="impala32"/> |
| </p> |
| |
| </conbody> |
| |
| </concept> |