On 12/01/2014 02:44 PM, Teodor Sigaev wrote:

Initial message:
http://www.postgresql.org/message-id/5447b3ff.2080...@sigaev.ru

Second version fixes a forgotten changes in pg_am.

+               /* Get the information we need about each relevant datatypes */
+
+               if (OidIsValid(cache->config.leafType) && 
cache->config.leafType != atttype)
+               {
+                       if (!OidIsValid(index_getprocid(index, 1, 
SPGIST_COMPRESS_PROC)))
+                               ereport(ERROR,
+                                               
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+                                                errmsg("compress method is not 
defined although input and leaf types are differ")));
+
+                       fillTypeDesc(&cache->attType, cache->config.leafType);
+               }
+               else
+               {
+                       fillTypeDesc(&cache->attType, atttype);
+               }
+

For some datatypes, the compress method might be useful even if the leaf type is the same as the column type. For example, you could allow indexing text datums larger than the page size, with a compress function that just truncates the input.

Could you find some use for this in one of the built-in or contrib types? Just to have something that exercises it as part of the regression suite. How about creating an opclass for the built-in polygon type that stores the bounding box, like the PostGIS guys are doing?

The documentation needs to be updated.

- Heikki



--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

Reply via email to