lib: Add non-content terms with a WDF value of 0.

The WDF is the "within-document frequency" value for a particular
term. It's intended to provide an indication of how frequent a term is
within a document, (for use in computing relevance). Xapian's term
generator already computes WDF values when we use that, (which we do
for indexing all mail content).

We don't use the term generator when adding single terms for things
that don't actually appear in the mail document, (such as tags, the
filename, etc.). In this case, the WDF value for these terms doesn't
matter much.

But Xapian's flint backend can be more efficient with changes to terms
that don't affect the document "length". So there's a performance
advantage for manipulating tags (with the flint backend) if the WDF of
these terms is 0.
This commit is contained in:
Carl Worth 2010-01-09 11:18:27 -08:00
parent 45b1856782
commit ccf2e0cc42
2 changed files with 4 additions and 4 deletions

View file

@ -213,7 +213,7 @@ _notmuch_directory_create (notmuch_database_t *notmuch,
Xapian::docid parent_id;
char *term = talloc_asprintf (local, "%s%s",
_find_prefix ("directory"), db_path);
directory->doc.add_term (term);
directory->doc.add_term (term, 0);
directory->doc.set_data (path);
@ -225,7 +225,7 @@ _notmuch_directory_create (notmuch_database_t *notmuch,
term = talloc_asprintf (local, "%s%u:%s",
_find_prefix ("directory-direntry"),
parent_id, basename);
directory->doc.add_term (term);
directory->doc.add_term (term, 0);
}
directory->doc.add_value (NOTMUCH_VALUE_TIMESTAMP,

View file

@ -192,7 +192,7 @@ _notmuch_message_create_for_message_id (notmuch_database_t *notmuch,
db = static_cast<Xapian::WritableDatabase *> (notmuch->xapian_db);
try {
doc.add_term (term);
doc.add_term (term, 0);
talloc_free (term);
doc.add_value (NOTMUCH_VALUE_MESSAGE_ID, message_id);
@ -646,7 +646,7 @@ _notmuch_message_add_term (notmuch_message_t *message,
if (strlen (term) > NOTMUCH_TERM_MAX)
return NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG;
message->doc.add_term (term);
message->doc.add_term (term, 0);
talloc_free (term);