试图在 bigtable 中模拟单元级 TTL，但整个列族数据被垃圾收集删除

Question

创建了一个具有以下规则的表：因此，数据应在 1 秒后过期（根据文档）

async function createTable() {
    console.log("Creating Table");
    const options = {
        families: [
            {
                name: 'payloads',
                rule: {
                    age: {
                        seconds: 1,
                        nanos: 0,
                    },
                },
            },
        ],
    };
    try {
        await table.create(options);
        console.log("Successfully Created Table");
    } catch (err) {
        console.error(`Error reading rows :`, err);
    }
}

然后像这样插入数据：

      const rowsToInsert = {
            key: "SUMEET",
            data: {
                payloads: {
                    '1': {
                        value: "NOTIFICATIONS_PAYLOAD_1",
                        timestamp: 1576500927000,
                    },
                    '2': {
                        value: "NOTIFICATIONS_PAYLOAD_2",
                        timestamp: 1576587327000,
                    },
                    '3': {
                        value: "NOTIFICATIONS_PAYLOAD_3",
                        timestamp: 1576673727000,
                    },
                    '4': {
                        value: "NOTIFICATIONS_PAYLOAD_4",
                        timestamp: 1576760127000,
                    },
                },
            },
        };

        await table.insert(rowsToInsert);

所以我添加了四个具有不同时间戳的单元格：

1. 首先在写入数据时提前 5 分钟
2. 领先 1 小时的第二名
3. 第三名，提前 1 天
4. 第四名，提前 2 天

这里的问题是当我读取数据时整个列族数据被删除但它应该只根据规则集删除第一个和第二个单元格

有什么遗漏或做错了吗？

Answer 1

问题在于您的时间戳，您很可能设置的是过去的日期。我建议您使用 javascript 中的日期方法设置日期，而不是像现在一样手动设置它们。

我用以下代码做了一些测试：

const Bigtable = require('@google-cloud/bigtable');
const bigtable = Bigtable();
const instance = bigtable.instance([instance]);
const table = instance.table([table]);
const now = new Date();


async function writeSimple() {
    var now = new Date(Date.now());
    var fiveMinutes = new Date(now.getTime() + 5 * 60000);
    var anHour = new Date(now.getTime() + 60 * 60000);
    var aDay = new Date(now.getTime() + 24 * 60 * 60000);
    var twoDays = new Date(now.getTime() + 48 * 60 * 60000);
  const rowsToInsert = {
            key: "SUMEET",
            data: {
                payloads: {
                    '1': {
                        value: "NOTIFICATIONS_PAYLOAD_1",
                        timestamp: now,
                    },
                    '2': {
                        value: "NOTIFICATIONS_PAYLOAD_2",
                        timestamp: fiveMinutes,
                    },
                    '3': {
                        value: "NOTIFICATIONS_PAYLOAD_3",
                        timestamp: anHour,
                    },
                    '4': {
                        value: "NOTIFICATIONS_PAYLOAD_4",
                        timestamp: aDay,
                    },
                    '5': {
                        value: "NOTIFICATIONS_PAYLOAD_5",
                        timestamp: twoDays,
                    },
                },
            },
        };

        await table.insert(rowsToInsert);
        console.log(`Successfully wrote row ${rowsToInsert.key}`);
}

并获得如下一行：

2019/12/17 16:53:33 -creds flag unset, will use gcloud credential
----------------------------------------
SUMEET
  payloads:1                               @ 2019/12/17-16:30:34.343000
    "NOTIFICATIONS_PAYLOAD_1"
  payloads:2                               @ 2019/12/17-16:35:34.343000
    "NOTIFICATIONS_PAYLOAD_2"
  payloads:3                               @ 2019/12/17-17:30:34.343000
    "NOTIFICATIONS_PAYLOAD_3"
  payloads:4                               @ 2019/12/18-16:30:34.343000
    "NOTIFICATIONS_PAYLOAD_4"
  payloads:5                               @ 2019/12/19-16:30:34.343000
    "NOTIFICATIONS_PAYLOAD_5"

垃圾收集器通过后（大约 15 分钟后）我得到了您想要的结果：

2019/12/17 16:59:47 -creds flag unset, will use gcloud credential
----------------------------------------
SUMEET
  payloads:3                               @ 2019/12/17-17:30:34.343000
    "NOTIFICATIONS_PAYLOAD_3"
  payloads:4                               @ 2019/12/18-16:30:34.343000
    "NOTIFICATIONS_PAYLOAD_4"
  payloads:5                               @ 2019/12/19-16:30:34.343000
    "NOTIFICATIONS_PAYLOAD_5"

希望这个对你有帮助！