On Jul 3, 2005, at 8:35 AM, Bruce Momjian wrote:

Andreas Pflug wrote:

Dave Page wrote:

Yup, attached. Per our earlier conversation, pg_dbfile_size() now
returns the size of a table or index, and pg_relation_size() returns the
total size of a relation and all associated indexes and toast tables

pg_relation_size's name is quite unfortunate, since the 8.0 contrib
function does something different. And pg_dbfile_size sounds misleading,
suggesting it takes a filename or relfilenode as parameter.

Hmm. I don't see how we can call it pg_table_size because people think
of tables and indexes, while relation has a more inclusive suggestion.

I'm not familiar enough with the backend code to know if there's a semantic difference between how relation and table are treated, so my line of reasoning may be flawed. However, I try to use the term relation when I'm discussing things at a logical level--the predicates the data represents. Indexes and toast tables are implementation details, separate from the predicates the relation represents.

The distinction between table and relation is very small, and using both pg_table_size and pg_relation_size but with different meanings is going to have people dependent on the documentation to remember the difference; pg_table_size and pg_relation_size both have the same meaning to me: the size of the table or index. I'd lean towards pg_table_size because this has a looser meaning that more easily includes indexes. An index doesn't really contain predicates and one doesn't store things in them directly.

I think what's needed is a term that expresses the more inclusive or implementation-specific nature of the function that returns table + indexes + toast tables + kitchen sink.

pg_tableall_size? pg_tablefull_size? pg_tableplus_size? pg_tableandmore_size? pg_tableimplementation_size? pg_tablekitchensink_size? ;)

I recognize the desire to have a relatively short name for the functions, but perhaps a longer one is needed to capture the distinction between the two. (Though it's kind of frustrating that none of us have been able to hit on a term that accurately and succinctly describes it.)

Michael Glaesemann
grzm myrealbox com

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