Index: src/docs/src/documentation/content/xdocs/supportedformats.xml =================================================================== --- src/docs/src/documentation/content/xdocs/supportedformats.xml (revision 1378855) +++ src/docs/src/documentation/content/xdocs/supportedformats.xml (working copy) @@ -26,6 +26,26 @@

Users can write SerDes for custom formats using the instructions at https://cwiki.apache.org/confluence/display/Hive/SerDe.

+

Usage from Hive

+

As of 0.4, Hive and HCatalog share the same storage abstractions, and thus, you can read from and write to HCatalog tables from within Hive, and vice versa.

+ +

However, Hive does not know where to find the HCatalog jar by default, so if you use any features that have been introduced by HCatalog, such as a table using the JSON SerDe, you might get a "class not found" exception. +In this situation, before you run Hive, set environment variable HIVE_AUX_JARS_PATH to the directory with your HCatalog jar. +(If the examples in the Installation document were followed, that should be /usr/local/hcat/share/hcatalog/).

+ +

CTAS Issue with JSON SerDe

+ +

Using the Hive CREATE TABLE ... AS SELECT command with a JSON SerDe +results in a table that has column headers such as "_col0", +which can be read by HCatalog or Hive but cannot be easily read by external users. +To avoid this issue, create the table in two steps instead of using CTAS:

+
    +
  1. CREATE TABLE ...
  2. +
  3. INSERT OVERWRITE TABLE ... SELECT ...
  4. +
+ +

See HCATALOG-436 for details.

+