CREATE TABLE post_likes
(
    id         BIGINT PRIMARY KEY,
    post_id    BIGINT      NOT NULL,
    user_id    BIGINT      NOT NULL,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),

    UNIQUE (post_id, user_id)
);

-- [核心索引] 优化 "feed流中判断我是否已赞" (user_id = ? AND post_id IN (...))
CREATE INDEX idx_post_likes_lookup ON post_likes (user_id, post_id);

-- [核心索引] 优化 "我赞过的帖子" 列表
CREATE INDEX idx_post_likes_user_timeline ON post_likes (user_id, created_at DESC);