docs - create ... external ... temp table (#5180)

* docs - create ... external ... temp table

* update CREATE EXTERNAL TABLE sgml docs

doc/src/sgml/ref/create_external_table.sgml

@@ -21,7 +21,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis> 
 
-CREATE [READABLE] EXTERNAL TABLE table_name 
+CREATE [READABLE] EXTERNAL [TEMPORARY | TEMP] TABLE table_name 
      ( column_name data_type [, ...] | LIKE other_table )
       LOCATION ('file://seghost[:port]/path/file' [, ...])
         | ('gpfdist://filehost[:port]/file_pattern[#transform]'
@@ -48,7 +48,7 @@ CREATE [READABLE] EXTERNAL TABLE table_name
      [ ENCODING 'encoding' ]
      [ [LOG ERRORS] SEGMENT REJECT LIMIT count
        [ROWS | PERCENT] ]
-CREATE [READABLE] EXTERNAL WEB TABLE table_name 
+CREATE [READABLE] EXTERNAL WEB [TEMPORARY | TEMP] TABLE table_name 
      ( column_name data_type [, ...] | LIKE other_table )
       LOCATION ('http://webhost[:port]/path/file' [, ...])
     | EXECUTE 'command' [ON ALL 
@@ -76,7 +76,7 @@ CREATE [READABLE] EXTERNAL WEB TABLE table_name
      [ ENCODING 'encoding' ]
      [ [LOG ERRORS] SEGMENT REJECT LIMIT count
        [ROWS | PERCENT] ]
-CREATE WRITABLE EXTERNAL TABLE table_name
+CREATE WRITABLE EXTERNAL [TEMPORARY | TEMP] TABLE table_name
     ( column_name data_type [, ...] | LIKE other_table )
      LOCATION('gpfdist://outputhost[:port]/filename[#transform]'
       | ('gpfdists://outputhost[:port]/file_pattern[#transform]'
@@ -95,7 +95,7 @@ CREATE WRITABLE EXTERNAL TABLE table_name
            | 'CUSTOM' (Formatter=<formatter specifications>)
     [ ENCODING 'write_encoding' ]
     [ DISTRIBUTED BY (column, [ ... ] ) | DISTRIBUTED RANDOMLY ]
-CREATE WRITABLE EXTERNAL WEB TABLE table_name
+CREATE WRITABLE EXTERNAL WEB [TEMPORARY | TEMP] TABLE table_name
     ( column_name data_type [, ...] | LIKE other_table )
     EXECUTE 'command' [ON ALL]
     FORMAT 'TEXT' 

gpdb-doc/dita/ref_guide/sql_commands/CREATE_EXTERNAL_TABLE.xml

@@ -7,7 +7,7 @@
     <p id="sql_command_desc">Defines a new external table.</p>
     <section id="section2">
       <title>Synopsis</title>
-      <codeblock id="sql_command_synopsis">CREATE [READABLE] EXTERNAL TABLE <varname>table_name</varname>     
+      <codeblock id="sql_command_synopsis">CREATE [READABLE] EXTERNAL [TEMPORARY | TEMP] TABLE <varname>table_name</varname>     
     ( <varname>column_name</varname> <varname>data_type</varname> [, ...] | LIKE <varname>other_table </varname>)
      LOCATION ('file://<varname>seghost</varname>[:<varname>port</varname>]/<varname>path</varname>/<varname>file</varname>' [, ...])
        | ('gpfdist://<varname>filehost</varname>[:<varname>port</varname>]/<varname>file_pattern</varname>[#transform=<varname>trans_name</varname>]'
@@ -41,7 +41,7 @@
       [ [LOG ERRORS] SEGMENT REJECT LIMIT <varname>count</varname>
       [ROWS | PERCENT] ]
 
-CREATE [READABLE] EXTERNAL WEB TABLE <varname>table_name</varname>     
+CREATE [READABLE] EXTERNAL WEB [TEMPORARY | TEMP] TABLE <varname>table_name</varname>     
    ( <varname>column_name</varname> <varname>data_type</varname> [, ...] | LIKE <varname>other_table </varname>)
       LOCATION ('http://<varname>webhost</varname>[:<varname>port</varname>]/<varname>path</varname>/<varname>file</varname>' [, ...])
     | EXECUTE '<varname>command</varname>' [ON ALL 
@@ -70,7 +70,7 @@ CREATE [READABLE] EXTERNAL WEB TABLE <varname>table_name</varname>
      [ [LOG ERRORS] SEGMENT REJECT LIMIT <varname>count</varname>
        [ROWS | PERCENT] ]
 
-CREATE WRITABLE EXTERNAL TABLE <varname>table_name</varname>
+CREATE WRITABLE EXTERNAL [TEMPORARY | TEMP] TABLE <varname>table_name</varname>
     ( <varname>column_name</varname> <varname>data_type</varname> [, ...] | LIKE <varname>other_table </varname>)
      LOCATION('gpfdist://<varname>outputhost</varname>[:<varname>port</varname>]/<varname>filename</varname>[#transform=<varname>trans_name</varname>]'
           [, ...])
@@ -94,7 +94,7 @@ CREATE WRITABLE EXTERNAL TABLE <varname>table_name</varname>
     [ ENCODING '<varname>write_encoding</varname>' ]
     [ DISTRIBUTED BY (<varname>column</varname>, [ ... ] ) | DISTRIBUTED RANDOMLY ]
 
-CREATE WRITABLE EXTERNAL TABLE <varname>table_name</varname>
+CREATE WRITABLE EXTERNAL [TEMPORARY | TEMP] TABLE <varname>table_name</varname>
     ( <varname>column_name</varname> <varname>data_type</varname> [, ...] | LIKE <varname>other_table </varname>)
      LOCATION('s3://<varname>S3_endpoint</varname>[:<varname>port</varname>]/<varname>bucket_name</varname>/[<varname>S3_prefix</varname>] [region=<varname>S3-region</varname>] [config=<varname>config_file</varname>]')
       [ON MASTER]
@@ -109,7 +109,7 @@ CREATE WRITABLE EXTERNAL TABLE <varname>table_name</varname>
                [FORCE QUOTE <varname>column</varname> [, ...]] ]
                [ESCAPE [AS] '<varname>escape</varname>'] )]
 
-CREATE WRITABLE EXTERNAL WEB TABLE <varname>table_name</varname>
+CREATE WRITABLE EXTERNAL WEB [TEMPORARY | TEMP] TABLE <varname>table_name</varname>
     ( <varname>column_name</varname> <varname>data_type</varname> [, ...] | LIKE <varname>other_table</varname> )
     EXECUTE '<varname>command</varname>' [ON ALL]
     FORMAT 'TEXT' 
@@ -174,6 +174,16 @@ CREATE WRITABLE EXTERNAL WEB TABLE <varname>table_name</varname>
             however, create an external web table that executes a third-party tool to read data from
             or write data to S3 directly.</pd>
         </plentry>
+        <plentry>
+          <pt>TEMPORARY | TEMP</pt>
+          <pd>If specified, creates a temporary readable or writable external table definition
+            in Greenplum Database. Temporary external tables exist in a special schema; you cannot
+            specify a schema name when you create the table. Temporary external tables are
+            automatically dropped at the end of a session.</pd>
+          <pd>An existing permanent table with the same name is not visible to the current session
+            while the temporary table exists, unless you reference the permanent table with its
+            schema-qualified name.</pd>
+        </plentry>
         <plentry>
           <pt>
             <varname>table_name</varname>