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| <!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
| <concept id="parquet_read_page_index"> |
| |
| <title>PARQUET_READ_PAGE_INDEX Query Option</title> |
| |
| <titlealts audience="PDF"> |
| |
| <navtitle>PARQUET_READ_PAGE_INDEX</navtitle> |
| |
| </titlealts> |
| |
| <prolog> |
| <metadata> |
| <data name="Category" value="Impala"/> |
| <data name="Category" value="Impala Query Options"/> |
| <data name="Category" value="Parquet"/> |
| <data name="Category" value="Developers"/> |
| <data name="Category" value="Data Analysts"/> |
| </metadata> |
| </prolog> |
| |
| <conbody> |
| |
| <p> |
| Use the <codeph>PARQUET_READ_PAGE_INDEX</codeph> query option to disable or enable using |
| the Parquet page index during scans. The page index contains min/max statistics at the |
| page-level granularity. It can be used to skip pages and rows that do not match the |
| conditions in the <codeph>WHERE</codeph> clause. |
| </p> |
| |
| <p> |
| This option enables the same optimization as the <codeph>PARQUET_READ_STATISTICS</codeph> |
| at the finer grained page level. |
| </p> |
| |
| <p> |
| Impala supports filtering based on Parquet statistics: |
| </p> |
| |
| <ul> |
| <li> |
| Of the types: Boolean, Integer, Decimal, String, Timestamp |
| </li> |
| |
| <li> |
| For simple predicates of the forms: <codeph><slot> <op> <constant></codeph> or |
| <codeph><constant> <op> <slot></codeph>, where <codeph><op></codeph> is LT, |
| LE, GE, GT, and EQ |
| </li> |
| </ul> |
| |
| <p> |
| The supported values for the query option are: |
| <ul> |
| <li> |
| <codeph>true</codeph> (<codeph>1</codeph>): Read the page-level statistics from the |
| Parquet page index during query processing and filter out pages based on the |
| statistics. |
| </li> |
| |
| <li> |
| <codeph>false</codeph> (<codeph>0</codeph>): Do not use the Parquet page index. |
| </li> |
| |
| <li> |
| Any other values are treated as <codeph>false</codeph>. |
| </li> |
| </ul> |
| </p> |
| |
| <p> |
| <b>Type:</b> Boolean |
| </p> |
| |
| <p> |
| <b>Default:</b> <codeph>TRUE</codeph> |
| </p> |
| |
| </conbody> |
| |
| </concept> |