I'm currently working on a Java project which i need to prepare a big(to me) mysql database. I have to do web scraping using Jsoup and store the results into my database as well. As i estimated, i will have roughly 1,500,000 to 2,000,000 records to be inserted. In my first trial, i just use a loop to insert these records and it takes me one week to insert about 1/3 of my required records, which is too slow i think. Is it possible to make this process multi-threaded, so that i can have my records split into 3 sets, say 500,000 records per set, and then insert them into one database( one table specifically)?
Multi-threading isn't going to help you here. You'll just move the contention bottleneck from your app server to the database.
Instead, try using batch-inserts instead, they generally make this sort of thing orders of magnitude faster. See "3.4 Making Batch Updates" in the JDBC tutorial.
Edit: As @Jon commented, you need to decouple the fetching of the web pages from their insertion into the database, otherwise the whole process will go at the speed of the slowest operation. You could have multiple threads fetching web pages, which add the data to a queue data structure, and then have a single thread draining the queue into the database using a batch insert.
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