{ Error: errCode: -501001 resource system error | errMsg: document.get:fail [ResourceUnavailable.TransactionNotExist] Transaction does not exist on the server, transaction must be commit or abort in 30 seconds. Please check your request, but if the problem persists, contact us.; at document.get api; 

    at returnAsCloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:6086:16)

    at Object.returnAsFinalCloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:6100:15)

    at Promise (/var/user/node_modules/wx-server-sdk/index.js:1270:32)

    at 

    at process._tickCallback (internal/process/next_tick.js:188:7)

  errCode: -501001,

  errMsg: 'document.get:fail [ResourceUnavailable.TransactionNotExist] Transaction does not exist on the server, transaction must be commit or abort in 30 seconds. Please check your request, but if the problem persists, contact us.; at document.get api; ' }

Transaction does not exist on the server, transaction must be commit or abort in 30 seconds

事务不存在于服务器上？事务必须在30秒内提交或者终止？

我的事务代码的确是关联了三张表，也许会比较耗时。。

调用10次大概会有一次出现的概率。

还会爆出这样的错误：

{ code: 'DATABASE_TRANSACTION_FAIL',

  message: '[ResourceUnavailable.TransactionNotExist] Transaction does not exist on the server, transaction must be commit or abort in 30 seconds. Please check your request, but if the problem persists, contact us.',

  requestId: '1585703096928_0.49784180112680776_33619401-1585703097701_30_15269' }