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From jbap...@apache.org
Subject [33/51] [partial] incubator-impala git commit: IMPALA-3398: Add docs to main Impala branch.
Date Thu, 17 Nov 2016 23:12:11 GMT
http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/3be0f122/docs/topics/impala_drop_function.xml
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diff --git a/docs/topics/impala_drop_function.xml b/docs/topics/impala_drop_function.xml
new file mode 100644
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--- /dev/null
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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept rev="1.2" id="drop_function">
+
+  <title>DROP FUNCTION Statement</title>
+  <titlealts audience="PDF"><navtitle>DROP FUNCTION</navtitle></titlealts>
+  <prolog>
+    <metadata>
+      <data name="Category" value="Impala"/>
+      <data name="Category" value="SQL"/>
+      <data name="Category" value="DDL"/>
+      <data name="Category" value="Impala Functions"/>
+      <data name="Category" value="UDFs"/>
+      <data name="Category" value="Schemas"/>
+      <data name="Category" value="Developers"/>
+      <data name="Category" value="Data Analysts"/>
+    </metadata>
+  </prolog>
+
+  <conbody>
+
+    <p>
+      <indexterm audience="Cloudera">DROP FUNCTION statement</indexterm>
+      Removes a user-defined function (UDF), so that it is not available for execution during
Impala
+      <codeph>SELECT</codeph> or <codeph>INSERT</codeph> operations.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/syntax_blurb"/>
+
+    <p>
+      To drop C++ UDFs and UDAs:
+    </p>
+
+<codeblock>DROP [AGGREGATE] FUNCTION [IF EXISTS] [<varname>db_name</varname>.]<varname>function_name</varname>(<varname>type</varname>[,
<varname>type</varname>...])</codeblock>
+
+    <note rev="2.5.0 IMPALA-2843 CDH-39148">
+      <p rev="2.5.0 IMPALA-2843 CDH-39148">
+        The preceding syntax, which includes the function signature, also applies to Java
UDFs that were created
+        using the corresponding <codeph>CREATE FUNCTION</codeph> syntax that
includes the argument and return types.
+        After upgrading to <keyword keyref="impala25_full"/> or higher, consider re-creating
all Java UDFs with the
+        <codeph>CREATE FUNCTION</codeph> syntax that does not include the function
signature. Java UDFs created this
+        way are now persisted in the metastore database and do not need to be re-created
after an Impala restart.
+      </p>
+    </note>
+
+    <p rev="2.5.0 IMPALA-2843 CDH-39148">
+      To drop Java UDFs (created using the <codeph>CREATE FUNCTION</codeph> syntax
with no function signature):
+    </p>
+
+<codeblock rev="2.5.0">DROP FUNCTION [IF EXISTS] [<varname>db_name</varname>.]<varname>function_name</varname></codeblock>
+
+<!--
+Examples:
+CREATE FUNCTION IF NOT EXISTS foo location '/path/to/jar' SYMBOL='TestUdf';
+CREATE FUNCTION bar location '/path/to/jar' SYMBOL='TestUdf2';
+DROP FUNCTION foo;
+DROP FUNCTION IF EXISTS bar;
+-->
+
+    <p conref="../shared/impala_common.xml#common/ddl_blurb"/>
+
+    <p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
+
+    <p>
+      Because the same function name could be overloaded with different argument signatures,
you specify the
+      argument types to identify the exact function to drop.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/restrictions_blurb"/>
+
+    <p conref="../shared/impala_common.xml#common/udf_persistence_restriction"/>
+
+    <p conref="../shared/impala_common.xml#common/cancel_blurb_no"/>
+
+    <p conref="../shared/impala_common.xml#common/permissions_blurb"/>
+    <p rev="CDH-19187">
+      The user ID that the <cmdname>impalad</cmdname> daemon runs under,
+      typically the <codeph>impala</codeph> user, does not need any
+      particular HDFS permissions to perform this statement.
+      All read and write operations are on the metastore database,
+      not HDFS files and directories.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/example_blurb"/>
+    <p rev="2.5.0 IMPALA-2843 CDH-39148">
+      The following example shows how to drop Java functions created with the signatureless
+      <codeph>CREATE FUNCTION</codeph> syntax in <keyword keyref="impala25_full"/>
and higher.
+      Issuing <codeph>DROP FUNCTION <varname>function_name</varname></codeph>
removes all the
+      overloaded functions under that name.
+      (See <xref href="impala_create_function.xml#create_function"/> for a longer example
+      showing how to set up such functions in the first place.)
+    </p>
+<codeblock rev="2.5.0 IMPALA-2843 CDH-39148">
+create function my_func location '/user/impala/udfs/udf-examples-cdh570.jar'
+  symbol='com.cloudera.impala.TestUdf';
+
+show functions;
++-------------+---------------------------------------+-------------+---------------+
+| return type | signature                             | binary type | is persistent |
++-------------+---------------------------------------+-------------+---------------+
+| BIGINT      | my_func(BIGINT)                       | JAVA        | true          |
+| BOOLEAN     | my_func(BOOLEAN)                      | JAVA        | true          |
+| BOOLEAN     | my_func(BOOLEAN, BOOLEAN)             | JAVA        | true          |
+...
+| BIGINT      | testudf(BIGINT)                       | JAVA        | true          |
+| BOOLEAN     | testudf(BOOLEAN)                      | JAVA        | true          |
+| BOOLEAN     | testudf(BOOLEAN, BOOLEAN)             | JAVA        | true          |
+...
+
+drop function my_func;
+show functions;
++-------------+---------------------------------------+-------------+---------------+
+| return type | signature                             | binary type | is persistent |
++-------------+---------------------------------------+-------------+---------------+
+| BIGINT      | testudf(BIGINT)                       | JAVA        | true          |
+| BOOLEAN     | testudf(BOOLEAN)                      | JAVA        | true          |
+| BOOLEAN     | testudf(BOOLEAN, BOOLEAN)             | JAVA        | true          |
+...
+</codeblock>
+
+    <p conref="../shared/impala_common.xml#common/related_info"/>
+
+    <p>
+      <xref href="impala_udf.xml#udfs"/>, <xref href="impala_create_function.xml#create_function"/>
+    </p>
+  </conbody>
+</concept>

http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/3be0f122/docs/topics/impala_drop_role.xml
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diff --git a/docs/topics/impala_drop_role.xml b/docs/topics/impala_drop_role.xml
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index 0000000..7383b46
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+++ b/docs/topics/impala_drop_role.xml
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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept rev="1.4.0" id="drop_role">
+
+  <title>DROP ROLE Statement (<keyword keyref="impala20"/> or higher only)</title>
+  <titlealts audience="PDF"><navtitle>DROP ROLE</navtitle></titlealts>
+  <prolog>
+    <metadata>
+      <data name="Category" value="Impala"/>
+      <data name="Category" value="DDL"/>
+      <data name="Category" value="SQL"/>
+      <data name="Category" value="Sentry"/>
+      <data name="Category" value="Security"/>
+      <data name="Category" value="Roles"/>
+      <data name="Category" value="Administrators"/>
+      <data name="Category" value="Developers"/>
+      <data name="Category" value="Data Analysts"/>
+      <!-- Consider whether to go deeper into categories like Security for the Sentry-related
statements. -->
+    </metadata>
+  </prolog>
+
+  <conbody>
+
+    <p>
+      <indexterm audience="Cloudera">DROP ROLE statement</indexterm>
+<!-- Copied from Sentry docs. Turn into conref. I did some rewording for clarity. -->
+      The <codeph>DROP ROLE</codeph> statement removes a role from the metastore
database. Once dropped, the role
+      is revoked for all users to whom it was previously assigned, and all privileges granted
to that role are
+      revoked. Queries that are already executing are not affected. Impala verifies the role
information
+      approximately every 60 seconds, so the effects of <codeph>DROP ROLE</codeph>
might not take effect for new
+      Impala queries for a brief period.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/syntax_blurb"/>
+
+<codeblock>DROP ROLE <varname>role_name</varname>
+</codeblock>
+
+    <p conref="../shared/impala_common.xml#common/privileges_blurb"/>
+
+    <p>
+      Only administrative users (initially, a predefined set of users specified in the Sentry
service configuration
+      file) can use this statement.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/compatibility_blurb"/>
+
+    <p>
+      Impala makes use of any roles and privileges specified by the <codeph>GRANT</codeph>
and
+      <codeph>REVOKE</codeph> statements in Hive, and Hive makes use of any roles
and privileges specified by the
+      <codeph>GRANT</codeph> and <codeph>REVOKE</codeph> statements
in Impala. The Impala <codeph>GRANT</codeph>
+      and <codeph>REVOKE</codeph> statements for privileges do not require the
<codeph>ROLE</codeph> keyword to be
+      repeated before each role name, unlike the equivalent Hive statements.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/related_info"/>
+
+    <p>
+      <xref href="impala_authorization.xml#authorization"/>, <xref href="impala_grant.xml#grant"/>
+      <xref href="impala_revoke.xml#revoke"/>, <xref href="impala_create_role.xml#create_role"/>,
+      <xref href="impala_show.xml#show"/>
+    </p>
+
+<!-- To do: nail down the new SHOW syntax, e.g. SHOW ROLES, SHOW CURRENT ROLES, SHOW GROUPS.
-->
+
+    <p conref="../shared/impala_common.xml#common/cancel_blurb_no"/>
+
+    <p conref="../shared/impala_common.xml#common/permissions_blurb_no"/>
+
+  </conbody>
+</concept>

http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/3be0f122/docs/topics/impala_drop_stats.xml
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diff --git a/docs/topics/impala_drop_stats.xml b/docs/topics/impala_drop_stats.xml
new file mode 100644
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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept rev="2.1.0" id="drop_stats">
+
+  <title>DROP STATS Statement</title>
+  <titlealts audience="PDF"><navtitle>DROP STATS</navtitle></titlealts>
+  <prolog>
+    <metadata>
+      <data name="Category" value="Impala"/>
+      <data name="Category" value="SQL"/>
+      <data name="Category" value="DDL"/>
+      <data name="Category" value="ETL"/>
+      <data name="Category" value="Ingest"/>
+      <data name="Category" value="Tables"/>
+      <data name="Category" value="Performance"/>
+      <data name="Category" value="Scalability"/>
+      <data name="Category" value="Developers"/>
+      <data name="Category" value="Data Analysts"/>
+    </metadata>
+  </prolog>
+
+  <conbody>
+
+    <p rev="2.1.0">
+      <indexterm audience="Cloudera">DROP STATS statement</indexterm>
+      Removes the specified statistics from a table or partition. The statistics were originally
created by the
+      <codeph>COMPUTE STATS</codeph> or <codeph>COMPUTE INCREMENTAL STATS</codeph>
statement.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/syntax_blurb"/>
+
+<codeblock rev="2.1.0">DROP STATS [<varname>database_name</varname>.]<varname>table_name</varname>
+DROP INCREMENTAL STATS [<varname>database_name</varname>.]<varname>table_name</varname>
PARTITION (<varname>partition_spec</varname>)
+
+<varname>partition_spec</varname> ::= <varname>partition_col</varname>=<varname>constant_value</varname>
+</codeblock>
+
+    <p conref="../shared/impala_common.xml#common/incremental_partition_spec"/>
+
+    <p>
+      <codeph>DROP STATS</codeph> removes all statistics from the table, whether
created by <codeph>COMPUTE
+      STATS</codeph> or <codeph>COMPUTE INCREMENTAL STATS</codeph>.
+    </p>
+
+    <p rev="2.1.0">
+      <codeph>DROP INCREMENTAL STATS</codeph> only affects incremental statistics
for a single partition, specified
+      through the <codeph>PARTITION</codeph> clause. The incremental stats are
marked as outdated, so that they are
+      recomputed by the next <codeph>COMPUTE INCREMENTAL STATS</codeph> statement.
+    </p>
+
+<!-- To do: what release was this added in? -->
+
+    <p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
+
+    <p>
+      You typically use this statement when the statistics for a table or a partition have
become stale due to data
+      files being added to or removed from the associated HDFS data directories, whether
by manual HDFS operations
+      or <codeph>INSERT</codeph>, <codeph>INSERT OVERWRITE</codeph>,
or <codeph>LOAD DATA</codeph> statements, or
+      adding or dropping partitions.
+    </p>
+
+    <p>
+      When a table or partition has no associated statistics, Impala treats it as essentially
zero-sized when
+      constructing the execution plan for a query. In particular, the statistics influence
the order in which
+      tables are joined in a join query. To ensure proper query planning and good query performance
and
+      scalability, make sure to run <codeph>COMPUTE STATS</codeph> or <codeph>COMPUTE
INCREMENTAL STATS</codeph> on
+      the table or partition after removing any stale statistics.
+    </p>
+
+    <p>
+      Dropping the statistics is not required for an unpartitioned table or a partitioned
table covered by the
+      original type of statistics. A subsequent <codeph>COMPUTE STATS</codeph>
statement replaces any existing
+      statistics with new ones, for all partitions, regardless of whether the old ones were
outdated. Therefore,
+      this statement was rarely used before the introduction of incremental statistics.
+    </p>
+
+    <p>
+      Dropping the statistics is required for a partitioned table containing incremental
statistics, to make a
+      subsequent <codeph>COMPUTE INCREMENTAL STATS</codeph> statement rescan
an existing partition. See
+      <xref href="impala_perf_stats.xml#perf_stats"/> for information about incremental
statistics, a new feature
+      available in Impala 2.1.0 and higher.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/ddl_blurb"/>
+
+    <p conref="../shared/impala_common.xml#common/cancel_blurb_no"/>
+
+    <p conref="../shared/impala_common.xml#common/permissions_blurb"/>
+    <p rev="CDH-19187">
+      The user ID that the <cmdname>impalad</cmdname> daemon runs under,
+      typically the <codeph>impala</codeph> user, does not need any
+      particular HDFS permissions to perform this statement.
+      All read and write operations are on the metastore database,
+      not HDFS files and directories.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/example_blurb"/>
+
+    <p>
+      The following example shows a partitioned table that has associated statistics produced
by the
+      <codeph>COMPUTE INCREMENTAL STATS</codeph> statement, and how the situation
evolves as statistics are dropped
+      from specific partitions, then the entire table.
+    </p>
+
+    <p>
+      Initially, all table and column statistics are filled in.
+    </p>
+
+<!-- Note: chopped off any excess characters at position 87 and after,
+           to avoid weird wrapping in PDF.
+           Applies to any subsequent examples with output from SHOW ... STATS too. -->
+
+<codeblock>show table stats item_partitioned;
++-------------+-------+--------+----------+--------------+---------+-----------------
+| i_category  | #Rows | #Files | Size     | Bytes Cached | Format  | Incremental stats
++-------------+-------+--------+----------+--------------+---------+-----------------
+| Books       | 1733  | 1      | 223.74KB | NOT CACHED   | PARQUET | true
+| Children    | 1786  | 1      | 230.05KB | NOT CACHED   | PARQUET | true
+| Electronics | 1812  | 1      | 232.67KB | NOT CACHED   | PARQUET | true
+| Home        | 1807  | 1      | 232.56KB | NOT CACHED   | PARQUET | true
+| Jewelry     | 1740  | 1      | 223.72KB | NOT CACHED   | PARQUET | true
+| Men         | 1811  | 1      | 231.25KB | NOT CACHED   | PARQUET | true
+| Music       | 1860  | 1      | 237.90KB | NOT CACHED   | PARQUET | true
+| Shoes       | 1835  | 1      | 234.90KB | NOT CACHED   | PARQUET | true
+| Sports      | 1783  | 1      | 227.97KB | NOT CACHED   | PARQUET | true
+| Women       | 1790  | 1      | 226.27KB | NOT CACHED   | PARQUET | true
+| Total       | 17957 | 10     | 2.25MB   | 0B           |         |
++-------------+-------+--------+----------+--------------+---------+-----------------
+show column stats item_partitioned;
++------------------+-----------+------------------+--------+----------+--------------
+| Column           | Type      | #Distinct Values | #Nulls | Max Size | Avg Size
++------------------+-----------+------------------+--------+----------+--------------
+| i_item_sk        | INT       | 19443            | -1     | 4        | 4
+| i_item_id        | STRING    | 9025             | -1     | 16       | 16
+| i_rec_start_date | TIMESTAMP | 4                | -1     | 16       | 16
+| i_rec_end_date   | TIMESTAMP | 3                | -1     | 16       | 16
+| i_item_desc      | STRING    | 13330            | -1     | 200      | 100.302803039
+| i_current_price  | FLOAT     | 2807             | -1     | 4        | 4
+| i_wholesale_cost | FLOAT     | 2105             | -1     | 4        | 4
+| i_brand_id       | INT       | 965              | -1     | 4        | 4
+| i_brand          | STRING    | 725              | -1     | 22       | 16.1776008605
+| i_class_id       | INT       | 16               | -1     | 4        | 4
+| i_class          | STRING    | 101              | -1     | 15       | 7.76749992370
+| i_category_id    | INT       | 10               | -1     | 4        | 4
+| i_manufact_id    | INT       | 1857             | -1     | 4        | 4
+| i_manufact       | STRING    | 1028             | -1     | 15       | 11.3295001983
+| i_size           | STRING    | 8                | -1     | 11       | 4.33459997177
+| i_formulation    | STRING    | 12884            | -1     | 20       | 19.9799995422
+| i_color          | STRING    | 92               | -1     | 10       | 5.38089990615
+| i_units          | STRING    | 22               | -1     | 7        | 4.18690013885
+| i_container      | STRING    | 2                | -1     | 7        | 6.99259996414
+| i_manager_id     | INT       | 105              | -1     | 4        | 4
+| i_product_name   | STRING    | 19094            | -1     | 25       | 18.0233001708
+| i_category       | STRING    | 10               | 0      | -1       | -1
++------------------+-----------+------------------+--------+----------+--------------
+</codeblock>
+
+    <p>
+      To remove statistics for particular partitions, use the <codeph>DROP INCREMENTAL
STATS</codeph> statement.
+      After removing statistics for two partitions, the table-level statistics reflect that
change in the
+      <codeph>#Rows</codeph> and <codeph>Incremental stats</codeph>
fields. The counts, maximums, and averages of
+      the column-level statistics are unaffected.
+    </p>
+
+    <note>
+      (It is possible that the row count might be preserved in future after a <codeph>DROP
INCREMENTAL
+      STATS</codeph> statement. Check the resolution of the issue
+      <xref href="https://issues.cloudera.org/browse/IMPALA-1615" scope="external" format="html">IMPALA-1615</xref>.)
+    </note>
+
+<codeblock>drop incremental stats item_partitioned partition (i_category='Sports');
+drop incremental stats item_partitioned partition (i_category='Electronics');
+
+show table stats item_partitioned
++-------------+-------+--------+----------+--------------+---------+------------------
+| i_category  | #Rows | #Files | Size     | Bytes Cached | Format  | Incremental stats
++-------------+-------+--------+----------+--------------+---------+-----------------
+| Books       | 1733  | 1      | 223.74KB | NOT CACHED   | PARQUET | true
+| Children    | 1786  | 1      | 230.05KB | NOT CACHED   | PARQUET | true
+| Electronics | -1    | 1      | 232.67KB | NOT CACHED   | PARQUET | false
+| Home        | 1807  | 1      | 232.56KB | NOT CACHED   | PARQUET | true
+| Jewelry     | 1740  | 1      | 223.72KB | NOT CACHED   | PARQUET | true
+| Men         | 1811  | 1      | 231.25KB | NOT CACHED   | PARQUET | true
+| Music       | 1860  | 1      | 237.90KB | NOT CACHED   | PARQUET | true
+| Shoes       | 1835  | 1      | 234.90KB | NOT CACHED   | PARQUET | true
+| Sports      | -1    | 1      | 227.97KB | NOT CACHED   | PARQUET | false
+| Women       | 1790  | 1      | 226.27KB | NOT CACHED   | PARQUET | true
+| Total       | 17957 | 10     | 2.25MB   | 0B           |         |
++-------------+-------+--------+----------+--------------+---------+-----------------
+show column stats item_partitioned
++------------------+-----------+------------------+--------+----------+--------------
+| Column           | Type      | #Distinct Values | #Nulls | Max Size | Avg Size
++------------------+-----------+------------------+--------+----------+--------------
+| i_item_sk        | INT       | 19443            | -1     | 4        | 4
+| i_item_id        | STRING    | 9025             | -1     | 16       | 16
+| i_rec_start_date | TIMESTAMP | 4                | -1     | 16       | 16
+| i_rec_end_date   | TIMESTAMP | 3                | -1     | 16       | 16
+| i_item_desc      | STRING    | 13330            | -1     | 200      | 100.302803039
+| i_current_price  | FLOAT     | 2807             | -1     | 4        | 4
+| i_wholesale_cost | FLOAT     | 2105             | -1     | 4        | 4
+| i_brand_id       | INT       | 965              | -1     | 4        | 4
+| i_brand          | STRING    | 725              | -1     | 22       | 16.1776008605
+| i_class_id       | INT       | 16               | -1     | 4        | 4
+| i_class          | STRING    | 101              | -1     | 15       | 7.76749992370
+| i_category_id    | INT       | 10               | -1     | 4        | 4
+| i_manufact_id    | INT       | 1857             | -1     | 4        | 4
+| i_manufact       | STRING    | 1028             | -1     | 15       | 11.3295001983
+| i_size           | STRING    | 8                | -1     | 11       | 4.33459997177
+| i_formulation    | STRING    | 12884            | -1     | 20       | 19.9799995422
+| i_color          | STRING    | 92               | -1     | 10       | 5.38089990615
+| i_units          | STRING    | 22               | -1     | 7        | 4.18690013885
+| i_container      | STRING    | 2                | -1     | 7        | 6.99259996414
+| i_manager_id     | INT       | 105              | -1     | 4        | 4
+| i_product_name   | STRING    | 19094            | -1     | 25       | 18.0233001708
+| i_category       | STRING    | 10               | 0      | -1       | -1
++------------------+-----------+------------------+--------+----------+--------------
+</codeblock>
+
+    <p>
+      To remove all statistics from the table, whether produced by <codeph>COMPUTE
STATS</codeph> or
+      <codeph>COMPUTE INCREMENTAL STATS</codeph>, use the <codeph>DROP
STATS</codeph> statement without the
+      <codeph>INCREMENTAL</codeph> clause). Now, both table-level and column-level
statistics are reset.
+    </p>
+
+<codeblock>drop stats item_partitioned;
+
+show table stats item_partitioned
++-------------+-------+--------+----------+--------------+---------+------------------
+| i_category  | #Rows | #Files | Size     | Bytes Cached | Format  | Incremental stats
++-------------+-------+--------+----------+--------------+---------+------------------
+| Books       | -1    | 1      | 223.74KB | NOT CACHED   | PARQUET | false
+| Children    | -1    | 1      | 230.05KB | NOT CACHED   | PARQUET | false
+| Electronics | -1    | 1      | 232.67KB | NOT CACHED   | PARQUET | false
+| Home        | -1    | 1      | 232.56KB | NOT CACHED   | PARQUET | false
+| Jewelry     | -1    | 1      | 223.72KB | NOT CACHED   | PARQUET | false
+| Men         | -1    | 1      | 231.25KB | NOT CACHED   | PARQUET | false
+| Music       | -1    | 1      | 237.90KB | NOT CACHED   | PARQUET | false
+| Shoes       | -1    | 1      | 234.90KB | NOT CACHED   | PARQUET | false
+| Sports      | -1    | 1      | 227.97KB | NOT CACHED   | PARQUET | false
+| Women       | -1    | 1      | 226.27KB | NOT CACHED   | PARQUET | false
+| Total       | -1    | 10     | 2.25MB   | 0B           |         |
++-------------+-------+--------+----------+--------------+---------+------------------
+show column stats item_partitioned
++------------------+-----------+------------------+--------+----------+----------+
+| Column           | Type      | #Distinct Values | #Nulls | Max Size | Avg Size |
++------------------+-----------+------------------+--------+----------+----------+
+| i_item_sk        | INT       | -1               | -1     | 4        | 4        |
+| i_item_id        | STRING    | -1               | -1     | -1       | -1       |
+| i_rec_start_date | TIMESTAMP | -1               | -1     | 16       | 16       |
+| i_rec_end_date   | TIMESTAMP | -1               | -1     | 16       | 16       |
+| i_item_desc      | STRING    | -1               | -1     | -1       | -1       |
+| i_current_price  | FLOAT     | -1               | -1     | 4        | 4        |
+| i_wholesale_cost | FLOAT     | -1               | -1     | 4        | 4        |
+| i_brand_id       | INT       | -1               | -1     | 4        | 4        |
+| i_brand          | STRING    | -1               | -1     | -1       | -1       |
+| i_class_id       | INT       | -1               | -1     | 4        | 4        |
+| i_class          | STRING    | -1               | -1     | -1       | -1       |
+| i_category_id    | INT       | -1               | -1     | 4        | 4        |
+| i_manufact_id    | INT       | -1               | -1     | 4        | 4        |
+| i_manufact       | STRING    | -1               | -1     | -1       | -1       |
+| i_size           | STRING    | -1               | -1     | -1       | -1       |
+| i_formulation    | STRING    | -1               | -1     | -1       | -1       |
+| i_color          | STRING    | -1               | -1     | -1       | -1       |
+| i_units          | STRING    | -1               | -1     | -1       | -1       |
+| i_container      | STRING    | -1               | -1     | -1       | -1       |
+| i_manager_id     | INT       | -1               | -1     | 4        | 4        |
+| i_product_name   | STRING    | -1               | -1     | -1       | -1       |
+| i_category       | STRING    | 10               | 0      | -1       | -1       |
++------------------+-----------+------------------+--------+----------+----------+
+</codeblock>
+
+    <p conref="../shared/impala_common.xml#common/related_info"/>
+
+    <p>
+      <xref href="impala_compute_stats.xml#compute_stats"/>, <xref href="impala_show.xml#show_table_stats"/>,
+      <xref href="impala_show.xml#show_column_stats"/>, <xref href="impala_perf_stats.xml#perf_stats"/>
+    </p>
+  </conbody>
+</concept>

http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/3be0f122/docs/topics/impala_drop_table.xml
----------------------------------------------------------------------
diff --git a/docs/topics/impala_drop_table.xml b/docs/topics/impala_drop_table.xml
new file mode 100644
index 0000000..8a75158
--- /dev/null
+++ b/docs/topics/impala_drop_table.xml
@@ -0,0 +1,150 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="drop_table">
+
+  <title>DROP TABLE Statement</title>
+  <titlealts audience="PDF"><navtitle>DROP TABLE</navtitle></titlealts>
+  <prolog>
+    <metadata>
+      <data name="Category" value="Impala"/>
+      <data name="Category" value="SQL"/>
+      <data name="Category" value="DDL"/>
+      <data name="Category" value="Tables"/>
+      <data name="Category" value="Schemas"/>
+      <data name="Category" value="S3"/>
+      <data name="Category" value="Developers"/>
+      <data name="Category" value="Data Analysts"/>
+    </metadata>
+  </prolog>
+
+  <conbody>
+
+    <p>
+      <indexterm audience="Cloudera">DROP TABLE statement</indexterm>
+      Removes an Impala table. Also removes the underlying HDFS data files for internal tables,
although not for
+      external tables.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/syntax_blurb"/>
+
+<codeblock>DROP TABLE [IF EXISTS] [<varname>db_name</varname>.]<varname>table_name</varname>
<ph rev="2.3.0">[PURGE]</ph></codeblock>
+
+    <p>
+      <b>IF EXISTS clause:</b>
+    </p>
+
+    <p>
+      The optional <codeph>IF EXISTS</codeph> clause makes the statement succeed
whether or not the table exists.
+      If the table does exist, it is dropped; if it does not exist, the statement has no
effect. This capability is
+      useful in standardized setup scripts that remove existing schema objects and create
new ones. By using some
+      combination of <codeph>IF EXISTS</codeph> for the <codeph>DROP</codeph>
statements and <codeph>IF NOT
+      EXISTS</codeph> clauses for the <codeph>CREATE</codeph> statements,
the script can run successfully the first
+      time you run it (when the objects do not exist yet) and subsequent times (when some
or all of the objects do
+      already exist).
+    </p>
+
+    <p rev="2.3.0">
+      <b>PURGE clause:</b>
+    </p>
+
+    <p rev="2.3.0"> The optional <codeph>PURGE</codeph> keyword, available
in
+      <keyword keyref="impala23_full"/> and higher, causes Impala to remove the associated
+      HDFS data files immediately, rather than going through the HDFS trashcan
+      mechanism. Use this keyword when dropping a table if it is crucial to
+      remove the data as quickly as possible to free up space, or if there is a
+      problem with the trashcan, such as the trash cannot being configured or
+      being in a different HDFS encryption zone than the data files. </p>
+
+    <p conref="../shared/impala_common.xml#common/ddl_blurb"/>
+
+    <p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
+
+    <p>
+      By default, Impala removes the associated HDFS directory and data files for the table.
If you issue a
+      <codeph>DROP TABLE</codeph> and the data files are not deleted, it might
be for the following reasons:
+    </p>
+
+    <ul>
+      <li>
+        If the table was created with the
+        <codeph><xref href="impala_tables.xml#external_tables">EXTERNAL</xref></codeph>
clause, Impala leaves all
+        files and directories untouched. Use external tables when the data is under the control
of other Hadoop
+        components, and Impala is only used to query the data files from their original locations.
+      </li>
+
+      <li>
+        Impala might leave the data files behind unintentionally, if there is no HDFS location
available to hold
+        the HDFS trashcan for the <codeph>impala</codeph> user. See
+        <xref href="impala_prereqs.xml#prereqs_account"/> for the procedure to set
up the required HDFS home
+        directory.
+      </li>
+    </ul>
+
+    <p>
+      Make sure that you are in the correct database before dropping a table, either by issuing
a
+      <codeph>USE</codeph> statement first or by using a fully qualified name
+      <codeph><varname>db_name</varname>.<varname>table_name</varname></codeph>.
+    </p>
+
+    <p>
+      If you intend to issue a <codeph>DROP DATABASE</codeph> statement, first
issue <codeph>DROP TABLE</codeph>
+      statements to remove all the tables in that database.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/example_blurb"/>
+
+<codeblock>create database temporary;
+use temporary;
+create table unimportant (x int);
+create table trivial (s string);
+-- Drop a table in the current database.
+drop table unimportant;
+-- Switch to a different database.
+use default;
+-- To drop a table in a different database...
+drop table trivial;
+<i>ERROR: AnalysisException: Table does not exist: default.trivial</i>
+-- ...use a fully qualified name.
+drop table temporary.trivial;</codeblock>
+
+    <p conref="../shared/impala_common.xml#common/disk_space_blurb"/>
+
+    <p conref="../shared/impala_common.xml#common/s3_blurb"/>
+    <p rev="2.6.0 CDH-39913 IMPALA-1878">
+      The <codeph>DROP TABLE</codeph> statement can remove data files from S3
+      if the associated S3 table is an internal table.
+      In <keyword keyref="impala26_full"/> and higher, as part of improved support
for writing
+      to S3, Impala also removes the associated folder when dropping an internal table
+      that resides on S3.
+      See <xref href="impala_s3.xml#s3"/> for details about working with S3 tables.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/s3_drop_table_purge"/>
+
+    <p conref="../shared/impala_common.xml#common/s3_ddl"/>
+
+    <p conref="../shared/impala_common.xml#common/cancel_blurb_no"/>
+
+    <p conref="../shared/impala_common.xml#common/permissions_blurb"/>
+    <p rev="CDH-19187">
+      For an internal table, the user ID that the <cmdname>impalad</cmdname>
daemon runs under,
+      typically the <codeph>impala</codeph> user, must have write
+      permission for all the files and directories that make up the table.
+    </p>
+    <p>
+      For an external table, dropping the table only involves changes to metadata in the
metastore database.
+      Because Impala does not remove any HDFS files or directories when external tables are
dropped,
+      no particular permissions are needed for the associated HDFS files or directories.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/related_info"/>
+
+    <p>
+      <xref href="impala_tables.xml#tables"/>,
+      <xref href="impala_alter_table.xml#alter_table"/>, <xref href="impala_create_table.xml#create_table"/>,
+      <xref href="impala_partitioning.xml#partitioning"/>, <xref href="impala_tables.xml#internal_tables"/>,
+      <xref href="impala_tables.xml#external_tables"/>
+    </p>
+
+  </conbody>
+</concept>

http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/3be0f122/docs/topics/impala_drop_view.xml
----------------------------------------------------------------------
diff --git a/docs/topics/impala_drop_view.xml b/docs/topics/impala_drop_view.xml
new file mode 100644
index 0000000..627fd47
--- /dev/null
+++ b/docs/topics/impala_drop_view.xml
@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept rev="1.1" id="drop_view">
+
+  <title>DROP VIEW Statement</title>
+  <titlealts audience="PDF"><navtitle>DROP VIEW</navtitle></titlealts>
+  <prolog>
+    <metadata>
+      <data name="Category" value="Impala"/>
+      <data name="Category" value="SQL"/>
+      <data name="Category" value="DDL"/>
+      <data name="Category" value="Schemas"/>
+      <data name="Category" value="Tables"/>
+      <data name="Category" value="Views"/>
+    </metadata>
+  </prolog>
+
+  <conbody>
+
+    <p>
+      <indexterm audience="Cloudera">DROP VIEW statement</indexterm>
+      Removes the specified view, which was originally created by the <codeph>CREATE
VIEW</codeph> statement.
+      Because a view is purely a logical construct (an alias for a query) with no physical
data behind it,
+      <codeph>DROP VIEW</codeph> only involves changes to metadata in the metastore
database, not any data files in
+      HDFS.
+    </p>
+
+    <p conref="../shared/impala_common.xml#common/syntax_blurb"/>
+
+<codeblock>DROP VIEW [IF EXISTS] [<varname>db_name</varname>.]<varname>view_name</varname></codeblock>
+
+    <p conref="../shared/impala_common.xml#common/ddl_blurb"/>
+
+    <p conref="../shared/impala_common.xml#common/cancel_blurb_no"/>
+
+    <p conref="../shared/impala_common.xml#common/permissions_blurb_no"/>
+
+    <p conref="../shared/impala_common.xml#common/example_blurb"/>
+
+    <p conref="../shared/impala_common.xml#common/create_drop_view_examples"/>
+
+    <p conref="../shared/impala_common.xml#common/related_info"/>
+
+    <p>
+      <xref href="impala_views.xml#views"/>, <xref href="impala_create_view.xml#create_view"/>,
+      <xref href="impala_alter_view.xml#alter_view"/>
+    </p>
+  </conbody>
+</concept>


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