transactions

问题 First off my engine is innoDB and I already tried the following on mySQL: BEGIN; INSERT INTO `tbl_users`(...) VALUES (...) ROLLBACK(); And it works fine, meaning the problem wasn't in my mysql config. But when I tried this on my Laravel Model: public static function addNew($request, $department_id) { $result = array(); $now = Carbon::now(); DB::beginTransaction(); //Checking for existing Order to set appropriate starting ID $result = DB::select(" SELECT COUNT(`id`) AS 'count' FROM `tbl

问题 I'm using Firestore runTransaction method in a https Cloud function (running Express). What I want is ensure that if any of the read or write fails the other transaction reads or writes won't run or will rollback if needed. Transaction admin.firestore().runTransaction(async (t) => { const { uid, artworkUid, tagLabel } = req.body; if (!tagLabel) { return Promise.reject('Missing parameters: "tagLabel"'); } if (!artworkUid) { return Promise.reject('Missing parameters: "artworkUid"'); } if

问题 I'm using Firestore runTransaction method in a https Cloud function (running Express). What I want is ensure that if any of the read or write fails the other transaction reads or writes won't run or will rollback if needed. Transaction admin.firestore().runTransaction(async (t) => { const { uid, artworkUid, tagLabel } = req.body; if (!tagLabel) { return Promise.reject('Missing parameters: "tagLabel"'); } if (!artworkUid) { return Promise.reject('Missing parameters: "artworkUid"'); } if

问题 I had been using @Transactional annotations in my Service Layer. But to resolve an error due to Lazy Loading in View I had to use Open Session in View Filter . After this, without use of @Transaction itself a Session gets opened and transaction starts. So does that mean @Transactions are not required? How will transactions and roll-backs be handled, then in Service Layers? 回答1: The javadoc explains it: This filter makes Hibernate Sessions available via the current thread, which will be

问题 Sometimes it's desirable to use a higher isolation level than the default "read committed" for database operations in Django. The docs warn that: Under higher isolation levels, your application should be prepared to handle exceptions raised on serialization failures. But which specific exceptions indicate a serialization failure, versus some other problem with the query or transaction? A simple retry mechanism after a serialization failure might look like something like this: for retries in

问题 What are the benefits of using implicit transactions (TransactionScope) over explicit transactions (SQLTransaction)? I have spent some time investigating this and there are lots of websites that explain the differences between the two, which I do understand e.g. this one: http://sqlserverpedia.com/wiki/Transaction_Overview, and this one: named explicit & implicit transactions. I understand the properties of a Transaction i.e. ACID. I have also looked at the documentation on MSDN. I believe

问题 I would like to run a transaction operation in Google App Engine using google-cloud-ndb. I deployed this app. Here is my code. # -*- coding: utf-8 -*- from flask import Flask from google.cloud import ndb import time app = Flask(__name__) class Book(ndb.Model): hoge = ndb.IntegerProperty() class Book2(ndb.Model): hoge = ndb.IntegerProperty() @ndb.transactional() def test1(): ent = ndb.Key(Book, "a").get() print("after get: %s", ent) ent.hoge = ent.hoge + 1 ent.put() print("after put: %s", ent)

问题 I would like to run a transaction operation in Google App Engine using google-cloud-ndb. I deployed this app. Here is my code. # -*- coding: utf-8 -*- from flask import Flask from google.cloud import ndb import time app = Flask(__name__) class Book(ndb.Model): hoge = ndb.IntegerProperty() class Book2(ndb.Model): hoge = ndb.IntegerProperty() @ndb.transactional() def test1(): ent = ndb.Key(Book, "a").get() print("after get: %s", ent) ent.hoge = ent.hoge + 1 ent.put() print("after put: %s", ent)

问题 I am trying to wrap my head around Kafka transactions and exactly-once. I have created a transactional consumer and I want to ensure that I read and process all messages for a topic. Kafka still commits the offset if the transaction fails and the message is therefore lost. More formally, if a stream processing application consumes message A and produces message B such that B = F(A), then exactly once processing means that A is considered consumed if and only if B is successfully produced, and

问题 I am trying to wrap my head around Kafka transactions and exactly-once. I have created a transactional consumer and I want to ensure that I read and process all messages for a topic. Kafka still commits the offset if the transaction fails and the message is therefore lost. More formally, if a stream processing application consumes message A and produces message B such that B = F(A), then exactly once processing means that A is considered consumed if and only if B is successfully produced, and