[PATCH 3/4] lib: define specialized get_thread_id for use in thread subquery
David Bremner
david at tethera.net
Sat May 5 09:05:22 PDT 2018
The observation is that we are only using the messages to get there
thread_id, which is kindof a pessimal access pattern for the current
notmuch_message_get_thread_id
---
lib/message.cc | 17 +++++++++++++++++
lib/notmuch-private.h | 4 ++++
lib/thread-fp.cc | 2 +-
3 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/lib/message.cc b/lib/message.cc
index d5db89b6..b2067076 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -318,6 +318,23 @@ _notmuch_message_get_term (notmuch_message_t *message,
return value;
}
+/*
+ * For special applications where we only want the thread id, reading
+ * in all metadata is a heavy I/O penalty.
+ */
+const char *
+_notmuch_message_get_thread_id_only (notmuch_message_t *message)
+{
+
+ Xapian::TermIterator i = message->doc.termlist_begin ();
+ Xapian::TermIterator end = message->doc.termlist_end ();
+
+ message->thread_id = _notmuch_message_get_term (message, i, end,
+ _find_prefix ("thread"));
+ return message->thread_id;
+}
+
+
static void
_notmuch_message_ensure_metadata (notmuch_message_t *message, void *field)
{
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 1093429c..4598577f 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -537,6 +537,10 @@ _notmuch_message_database (notmuch_message_t *message);
void
_notmuch_message_remove_unprefixed_terms (notmuch_message_t *message);
+
+const char *
+_notmuch_message_get_thread_id_only(notmuch_message_t *message);
+
/* sha1.c */
char *
diff --git a/lib/thread-fp.cc b/lib/thread-fp.cc
index dd292bf6..661d00dd 100644
--- a/lib/thread-fp.cc
+++ b/lib/thread-fp.cc
@@ -50,7 +50,7 @@ ThreadFieldProcessor::operator() (const std::string & str)
std::string term = thread_prefix;
notmuch_message_t *message;
message = notmuch_messages_get (messages);
- term += notmuch_message_get_thread_id (message);
+ term += _notmuch_message_get_thread_id_only (message);
terms.insert (term);
}
return Xapian::Query (Xapian::Query::OP_OR, terms.begin (), terms.end ());
--
2.17.0
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