I’d like to return multiple values from the same record, with different columns of the same type appended under one another. I could do multiple joins, but that seems very inefficient because of the multiple table scans. Returns: VisID Vis Home HomeID arenn001 Nolan Arenado Colin Moran morac001 badeh001…
Tag: database-performance
How to store number in shortest possible size?
I will be adding comments into my website and I want to have a tree structure so each comment can have a parent. This creates a problem when retrieving comments because each comment would have to be traversed for children and this is unacceptable when it comes to database storage. There are various solutions …
Select distinct very slow
I have a table where I store rows with external ids. Quite often I need to select latest timestamp for given external ids. Now it is a bottleneck for my app Query: Explain: What could I do to make this query faster? Or probably should I use completely different query? UPDATE: Added new query plan as asked @ja…
How does i/o on database relate to query type
So I have metrics that look like this. And here is my dumb question… Does the rw i/o directly correlate to rw query? Using the example below, does that mean there was increased read query activity? I don’t have some flags enabled yet to have metrics on the transaction level, but i’ll eventua…
Does adding the guaranteed where condition on sql can improve performance?
Let’s say there’s a table about logging website access. (id is the only index column) | id | domain | logged_at | |—-|————|————————–| | 1 | yahoo.com |…
PostgreSQL: Bad query performance caused by unused index?
we have a query to get all jobs with changes inside a certain time period. Depending on the selected period the performance goes from
Select a conversation between exact users (by users IDs)
I’m woking on a simple chat app. It should allow users to run conversations user-to-user or in groups (multiple users). So here are my tables: table users ID | username | … table …
MS ACCESS SQL Join Subquery
I have two tables: newparts, storedparts I insert the parts of the newparts, which are not jet in the storedparts into the storedparts: This is working fine so far. Now the Problem: Table storedparts is getting so big that the programm is taking too Long for the join process. My solution: Just compare the new…