【数据存储】冷热分离：三个月未登录角色的归档

---全局定时器 30 号：每小时扫描一次归档
setontimerex(30, 3600)
function Archive.scan()
    local cutoff = os.time() - 90 * 86400
    local batch = DB.query(
        "SELECT id FROM roles WHERE last_login < ? AND hot = 1 LIMIT 500",
        cutoff)
    for _, row in ipairs(batch) do
        Archive.move(row.id)
    end
end

function Archive.move(roleId)
    DB.trans(function()
        local snap = DB.queryRow("SELECT * FROM roles WHERE id = ?", roleId)
        DB.exec("INSERT INTO roles_archive SET ?", snap)
        DB.exec("UPDATE roles SET hot = 0 WHERE id = ?", roleId)
    end)
end

---查询走主表，未命中回源归档表
function Archive.find(roleId)
    local row = DB.queryRow("SELECT * FROM roles WHERE id = ?", roleId)
    if not row or row.hot == 0 then
        row = DB.queryRow("SELECT * FROM roles_archive WHERE id = ?", roleId)
    end
    return row
end