Post your questions at https://pollgab.com/room/brento and upvote the ones you’d like to see me answer.
Here’s what we discussed today:
- 00:00 Start
- 01:40 prasad: Hi Brent, I want to become a full fledged database architect. I have been reading and practising lot of stuffs here and there, but no certain path. I also subscribed once to ur master class bundle. can you guide me on a proper path for the same? Thanks in advance
- 04:57 ExcitingAndNew: Hi Brent, what is your opinion on the practice of inserting SQL comments into SQL requests as tags to allow DBAs to track the requests in the server ? (I’m talking about comments for instance just after SELECT/INSERT/UPDATE/DELETE to force SQL Server to keep them everywhere)
- 05:40 DGW in OKC: What is your opinion on the practice of a manager who consistently assigns DBA tasks to an employee who is marginally proficient at DBA work and is not really that interested in this discipline anyway?
- 08:08 Fjola : sp_BlitzFirst shows the top expensive query of type : statement. It’s unclear which app/sp is generating this query. What is the best way to track down the app / sp generating this query / statement?
- 10:05 Chris: Have you ever had manually created statistics either be a root cause or the final push needed to cross the line?
- 10:53 CKI: How to get history of most recent queries executed with username in SQL? Auditing is not an option. Thank you!
- 11:50 Piotr: Do you have a recommended method for adding notes to a given NC index (i.e. why this index is needed, which app uses it)?
- 12:38 Perplexed: What are your thoughts on using PERSIST_SAMPLE_PERCENT to force all future UPDATE STATS to use a specific sampling? I just started using this on a very large table that was not getting stats right after updating the stats.
- 14:02 UncleFester: When running Select */Count(*) SQL was using an index, returning only 47 mil rows of 95 mil in the table. Rebuilding the index/statistics was no help. Dropping/recreating the index solved it. Can I really trust Select * or Select Count(*) to return all of the rows in the table?
- 14:56 RoJo: Debate rages here on what login to use for security: AD/Windows or SQL direct. Is either more secure? or if equal, do you prefer one and why? Thanks dude
We have some very large tables and we implement a 25% sample for any tables with over 200m rows. It seems to work for us but your milage may vary.
That totally works great in a lot of situations, even smaller sampling rates. For example, if you’re looking for item quantity on a sales line item table, heck, even a 1% sampling would probably be fine. Most sales are for 1 item, 2 items, 10 items, etc. Data distribution is pretty small.
Things get wildly different on sales date columns.