-- Add denormalized query keys. Ignored when 0011 already created the columns.

ALTER TABLE private_message
    ADD COLUMN receiver_id BIGINT NOT NULL DEFAULT 0 COMMENT '接收者 user_id；系统消息为 0';

ALTER TABLE private_message
    ADD KEY idx_receiver_id (receiver_id, id);

UPDATE private_message pm
INNER JOIN p2p_conversations p ON p.conversation_id = pm.conversation_id
SET pm.receiver_id = IF(pm.sender_id = p.user_small, p.user_big, IF(pm.sender_id = p.user_big, p.user_small, 0))
WHERE pm.receiver_id = 0 AND pm.sender_id <> 0;

ALTER TABLE group_message
    ADD COLUMN group_id BIGINT NOT NULL DEFAULT 0 COMMENT '群号 groups.id，便于按群查询';

ALTER TABLE group_message
    ADD KEY idx_group_id (group_id, id);

UPDATE group_message gm
INNER JOIN `groups` g ON g.conversation_id = gm.conversation_id
SET gm.group_id = g.id
WHERE gm.group_id = 0;