Performance fix for subscription/subscriber lists based on feedback from ops.

Extended subscription table indexes for subscriber and subscribed to include the created field, which is used to sort for display. This lets us skip a filesort and do the join much more efficiently.
Alter table from 08to09.sql needs to be run manually (though no ill effects if you forget other than not getting the perf improvement).

1 files changed, 6 insertions, 0 deletions

diff --git a/db/08to09.sql b/db/08to09.sql
index e6842225b..1d37a759d 100644
--- a/db/08to09.sql
+++ b/db/08to09.sql
@@ -45,3 +45,9 @@ create table login_token (
 alter table fave
     drop index fave_user_id_idx,
     add index fave_user_id_idx (user_id,modified);
+
+alter table subscription
+    drop index subscription_subscriber_idx,
+    add index subscription_subscriber_idx (subscriber,created),
+    drop index subscription_subscribed_idx,
+    add index subscription_subscribed_idx (subscribed,created);