- Rewritten messages caching (merged devel-mcache branch):

Indexes are stored in a separate table, so there's no need to store all messages in a folder
  Added threads data caching
  Flags are stored separately, so flag change doesn't cause DELETE+INSERT, just UPDATE
- Partial QRESYNC support
- Improved FETCH response handling
- Improvements in response tokenization method

SQL/postgres.update.sql

@@ -126,3 +126,46 @@ CREATE TABLE searches (
     data text NOT NULL,
     CONSTRAINT searches_user_id_key UNIQUE (user_id, "type", name)
 );
+
+DROP SEQUENCE messages_ids;
+DROP TABLE messages;
+
+CREATE TABLE cache_index (
+    user_id integer NOT NULL
+    	REFERENCES users (user_id) ON DELETE CASCADE ON UPDATE CASCADE,
+    mailbox varchar(255) NOT NULL,
+    changed timestamp with time zone DEFAULT now() NOT NULL,
+    data text NOT NULL,
+    PRIMARY KEY (user_id, mailbox)
+);
+
+CREATE INDEX cache_index_changed_idx ON cache_index (changed);
+
+CREATE TABLE cache_thread (
+    user_id integer NOT NULL
+    	REFERENCES users (user_id) ON DELETE CASCADE ON UPDATE CASCADE,
+    mailbox varchar(255) NOT NULL,
+    changed timestamp with time zone DEFAULT now() NOT NULL,
+    data text NOT NULL,
+    PRIMARY KEY (user_id, mailbox)
+);
+
+CREATE INDEX cache_thread_changed_idx ON cache_thread (changed);
+
+CREATE TABLE cache_messages (
+    user_id integer NOT NULL
+    	REFERENCES users (user_id) ON DELETE CASCADE ON UPDATE CASCADE,
+    mailbox varchar(255) NOT NULL,
+    uid integer NOT NULL,
+    changed timestamp with time zone DEFAULT now() NOT NULL,
+    data text NOT NULL,
+    seen smallint NOT NULL DEFAULT 0,
+    deleted smallint NOT NULL DEFAULT 0,
+    answered smallint NOT NULL DEFAULT 0,
+    forwarded smallint NOT NULL DEFAULT 0,
+    flagged smallint NOT NULL DEFAULT 0,
+    mdnsent smallint NOT NULL DEFAULT 0,
+    PRIMARY KEY (user_id, mailbox, uid)
+);
+
+CREATE INDEX cache_messages_changed_idx ON cache_messages (changed);