This post relates to the topic: Fix Tapatalk slow query, when creating a topic I am the administrator and part owner of a community with around 1,000 members online on average. We have exceeded 8.5 million posts and have 150,000+ members. We recently upgraded our servers with the latest RPMs from Axivo's repository, inclusive of Searchlight which now runs much faster. Although we have ample resources for our site (a cluster of 4 servers), we recently found that certain queries take 15 seconds to run (and even more) thus slowing the site down significantly. Initially we thought it was the Tapatalk application, which we got rid of finally replacing it with ForumRunner. ForumRunner is very well written and it takes advantage of Searchlight's features which is great! The query that has been extremely slow for us (thus locking the site down) was: Code: SELECT postid FROM vb_post WHERE threadid=527413 ORDER BY dateline LIMIT 1; This query would effectively bog the server down and we were trying to find why. I contacted Floren who pointed me to the topic listed at the top of this post. I made the necessary changes and the performance increased immensely. What the above query does, is to scan the whole vb_post table, filter the results by the threadid and then order them by dateline and pick the first row. This query could very well work for you if your topics/threads are rather small. However for the particular thread, we had around 3,000 replies. So in effect, the query would scan 8,500,000 rows, pick 3,000 from them, sort them and then get the first one. I run the query against our database server and the result came back in 25.41 seconds. Changing the query to: Code: SELECT firstpostid AS postid FROM vb_thread WHERE threadid=527413; brought the same result back in 0.01 seconds. Having this kind of query in the edit post and new post scripts significantly slows down your site, something that your users will not appreciate. Thank you again Floren!