Cannot find solution to MySQL Lost Update Problem
I’m trying to fix a lost update problem in MySQL, where two sessions do not update with each other. Basically, the question is as follows:
concurrency
MySQL INSERT IF (custom if statements)
First, here’s the concise summary of the question:
Is MySQL Temporary table a shared resource?
I have a MySQL stored procedure that uses a temporary table. Assume that my table name is ‘temp’ and I use it to store some middle data. It will create at the beginning of procedure, and will drop at the end.
MYSQL last_insert_id() and concurrency
I have a simple MYSQL question. If I make a query that contains LAST_INSERT_ID() right after an INSERT QUERY running on a web page which has many concurrent users accessing other pages that perform INSERT operations would the value of LAST_INSERT_ID() be adulterated/corrupted?
Is MySQL Connector/JDBC thread safe?
Is the standard MySQL JDBC driver thread-safe? Specifically I want to use a single connection across all threads, but each statement will only be used in a single thread. Are there certain scenarios that are safe and others that aren’t? What’s your experience here?
How to properly use transactions and locks to ensure database integrity?
I develop an online reservation system. To simplify let’s say that users can book multiple items and each item can be booked only once. Items are first added to the shopping cart.
Doctrine2 ORM select for update
Could you suggest an approach how to implement SELECT FOR UPDATE with Doctrine?
Optimistic concurrency with Entity Framework and MySQL
I’m currently developing an app using Entity Framework 4.1 and MySQL. I want to use optimistic concurrency and therefore need to create a table structure which allows EF to detect concurrency issues. My goal is something similar to this: http://blogs.msdn.com/b/alexj/archive/2009/05/20/tip-19-how-to-use-optimistic-concurrency-in-the-entity-framework.aspx.
Multithreading/Parallel Processing in PHP
I have a PHP script that will generate a report using PHPExcel from data queried from a MySQL DB. Currently, it is linear in processing in that it gets the data back from MySQL, reads in the Excel template, writes the data to the template, then outputs it. I have optimized the code to the point that the data is only iterated over once, and there is very little processing done on the PHP side. The query returns hundreds of lines in less than .001 seconds, so it is running fast enough. After some timing I have found my bottlenecks to be (surprise, surprise) reading the template and writing the output.
I would like to do this:
Does “SELECT FOR UPDATE” prevent other connections inserting when the row is not present?
I’m interested in whether a SELECT FOR UPDATE query will lock a non-existent row.