If we want to create an PXF plugin to allow an external data source to be both
readable and writable, we have to implement both ReadAccessor and WriteAccessor
interface.
However, when we create external table mapping, a table has to be either
readable or writable, but can't be both.
In this case we have to create two tables pointing to the same data source:
postgres=# \d+ t3
External table "public.t3"
Column | Type | Modifiers | Storage | Description
----------+-------------------+-----------+----------+-------------
id | integer | | plain |
total | integer | | plain |
comments | character varying | | extended |
Type: writable
Encoding: UTF8
Format type: custom
Format options: formatter 'pxfwritable_export'
External location: pxf://localhost:51200/foo.main?PROFILE=XXXX
postgres=# \d+ t4
External table "public.t4"
Column | Type | Modifiers | Storage | Description
-----------+-------------------+-----------+----------+-------------
recordkey | character varying | | extended |
id | integer | | plain |
total | integer | | plain |
comments | character varying | | extended |
Type: readable
Encoding: UTF8
Format type: custom
Format options: formatter 'pxfwritable_import'
External location: pxf://localhost:51200/foo.main?PROFILE=XXXX
postgres=# insert into t3 select * from t5 ;
INSERT 0 65536
postgres=# select count(*) from t4 ;
count
--------
131077
(1 row)
I wonder is there anyway we can create a table for both read and write purpose?
