Ignoring duplicate inserts with Postgres when processing a batch

I'm busy on a project which involves importing fairly large datasets of about ~3.3GB at a time. I have to read a CSV file, process each line, and generate a number of database records from the results of that process.

Users are expected to be able to rerun batches and there is overlap between different datasets. For example: the dataset of "last year" overlaps with the dataset of "all time". This means that we need an elegant way to handle duplicate updates.

Searching if a record exists (by PK) is fine until the row count in the table gets significant. At just over 2 million records it was taking my development machine 30 seconds to process 10,000 records. This number steadily increased as the row count increased.

I had to find a better way to do this and happened across the option of using a database rule to ignore duplicates. While using the rule there is a marked improvement in the performance as I no longer need to search the database for a record.

Comments

Separating business logic from persistence layer in Laravel

There are several reasons to separate business logic from your persistence layer. Perhaps the biggest advantage is that the parts of your application which are unique are not coupled to how data are persisted. This makes the code easier to port and maintain. I'm going to use Doctrine to replace the Eloquent ORM in Laravel. A thorough comparison of the patterns is available here . By using Doctrine I am also hoping to mitigate the risk of a major version upgrade on the underlying framework. It can be expected for the ORM to change between major versions of a framework and upgrading to a new release can be quite costly. Another advantage to this approach is to limit the access that objects have to the database. Unless a developer is aware of the business rules in place on an Eloquent model there is a chance they will mistakenly ignore them by calling the ActiveRecord save method directly. I'm not implementing the repository pattern in all its ...

Using Azure Active directory as an OAuth2 provider for Django

Azure Active Directory is a great product and is invaluable in the enterprise space. In this article we'll be setting it up to provide tokens for the OAuth2 client credentials grant. This authorization flow is useful when you want to authorize server-to-server communication that might not be on behalf of a user. This diagram, by Microsoft, shows the client credentials grant flow. From Microsoft documentation The flow goes like this: The client sends a request to Azure AD for a token Azure AD verifies the attached authentication information and issues an access token The client calls the API with the access token. The API server is able to verify the validity of the token and therefore the identity of the client. The API responds to the client Setting up Azure AD as an OAuth2 identity provider The first step is to create applications in your AD for both your API server and the client. You can find step-by-step instructions on how to register the applications o...

"Word of the Day" PHP script (with word list)

I was looking around for a way to generate a word of the day on the web and didn't find anything. So I coded a quick and dirty script to do it. Just in case anybody does a Google search and manages to find my blog: here is my Word of the Day PHP script : Copy this code snippet into a wordoftheday.php file: $file = fopen("interesting_words.txt","r"); $raw_string = fread($file,filesize("interesting_words.txt")); fclose($file); $words_array = explode("|",$raw_string); echo $words_array[array_rand($words_array)]; Of course the real issue I had was finding a list of interesting words in the right format. Here is the list of interesting words that I used: Copy this into a file called interesting_words.txt : ubiquitous : being or seeming to be everywhere at the same time; omnipresent| ecdysiast : a striptease artist| eleemosynary : of, relating to, or dependent on charity| gregious : c...

Adventures in IT

Search This Blog