What can cause higher CPU time and duration for a given set of queries in trace(s) ran on two separate environments?

I’m troubleshooting a performance issue in a SQL Server DR environment for a customer. They are running queries that consistently take longer in their environment than our QA environment. After analyzing traces that were performed in both environments with the same parameters/filters and with the same version of SQL Server (2016 SP2) and the exact same database, we observed that both environment were picking the same execution plan(s) for the queries in question, and the number of reads/writes were close in both environments, however the total duration of the process in question and the CPU time logged in the trace were significantly higher in the customer environment. Duration of all processes in our QA environment was around 18 seconds, the customer was over 80 seconds, our CPU time was close to 10 seconds, theirs was also over 80 seconds. Also worth mentioning, both environments are currently configured to MAXDOP 1.

The customer has less memory (~100GB vs 120GB), and slower disks (10k HHD vs SSD) than our QA environment, but but more CPUs. Both environments are dedicated to this activity and should have little/no external load that wouldn’t match. I don’t have all the details on CPU architecture they are using, waiting for some of that information now. The customer has confirmed they have excluded SQL Server and the data/log files from their virus scanning. Obviously there could be a ton of issues in the hardware configuration.

I’m currently waiting to see a recent snapshot of their wait stats and system DMVs, the data we originally received, didn’t appear to have any major CPU, memory or Disk latency pressure. I recently asked them to check to see if the windows power setting was in performance or balanced mode, however I’m not certain that would have the impact we’re seeing or not if the CPUs were being throttled.

My question is, what factors can affect CPU time and ultimately total duration? Is CPU time, as shown in a sql trace, based primarily on the speed of the processors or are their other factors I should be taking in to consideration. The fact that both are generating the same query plans and all other things being as close as possible to equal, makes me think it’s related to the hardware SQL is installed on.

Can a character wear both Chain mail and Leather to get a higher AC and to fool an enemy?

Background:
I am reading the anime book "Goblin Slayer", the light novel not the comic.

In it the main character wears leather armor over plate or chain to both stack his AC and to confuse his (not very intelligent) enemies into hitting where leather is vulnerable but plate or chain is not.

Question:
In dnd 5th edition, can one wear multiple types of armor and get an AC stack? Can it confuse weak foes like goblins?

Notes:
Here are answers that don’t speak to this question:

  • Can a chain shirt be concealed under normal clothing? (this is about concealed, I’m asking about stacked)
  • Stacking multiple types of armor (this is not dnd 5e centric)
  • Can you wear a Mithral Chain over Snakeskin Tunic and have their effect stack? (this is pathfinder)

Please, if you are going to down-vote, say why in the comments. If I don’t know what I did wrong, it is literally impossible for me to willfully act better and change that thing. It might happen by accident, but the universe doesn’t like happy accidents.

How can you cast a spell at a caster level much higher than 20?

Certain spells such as Mass Cure Critical Wounds have level-based effects with caps that are higher than 20 (in this case, 40). How is it possible to cast such spells and have the higher-than-20 cap actually matter?

I know there are some relatively uncommon ways to boost your CL by a little bit (e.g. Orange Prism, Moon Circlet, and Improved Caster Level, although ICL doesn’t give you a bonus higher than your character level, which makes it irrelevant for this), but these are tiny bonuses. Is it even possible to cast something like Mass Cure Critical Wounds and heal for the full +40 hp?

Is there any leeway with choosing my starting items if I’m starting at a level higher than 1?

I’m preparing a Cleric for a Pathfinder 2nd Ed campaign and reached a bit of an impasse. Going by Table 10-10, my character should have one permanent 2nd level item, 2 permanent 1st level items and 25GP of other funds. The problem is that the 1st level items are either redundant (everburning torch and dull aeon stone) or are unusable for my character (Heavy Armors). Considering these factors, I have a few questions:

1) Can a selection of a permanent item be exchanged for multiple selections of consumable items of the same level? If so, how many?

2) Can you take a lump sum of GP instead of a permanent item? If so, how much?

What is the best way to help a new player join a higher level party?

Having spent lockdown watching us play from the sidelines, and having played in one shots of a couple of different systems. One of our party’s partners would like to join the d&d campaign I am running. As a DM I have no issues with this, she gets the game and has been reading the rules and the party of 4 could easily accept a 5th member.

However I am now wondering how best to create her character with her. In the past when a party member has joined a campaign I am running they are not new to role playing, this is not their first campaign and so they have already experienced taking a level 1 character through the ranks, therefore starting them at the same or a slightly lower level then the party is not an issue, they have played enough to be able to quickly pick up all the extra skills and abilities a sudden jump gives them, the magic items I allow them to start with at that level are not something more to learn to use. The party are all roughly levels 8-10 so I can’t bring her on as a level 1 character.

What is the best way to help her not feel overwhelmed by everything while allowing her to jump in with a more powerful character then most starT with. She hasn’t yet told me her race or class, we are planning an evening together to flesh all that out soon and I would like to go in prepared with some tips to help her get the most out of this and not spend the first few sessions feeling lost as she tries to remember everything her character can do.

Casting a cantrip on a higher level when multiclassing [duplicate]

Some cantrips such as ‘Thunderclap’ says in higher level(not in higher spell slot), we can give more damage.

Thunderclap

Casting Time: 1 action Range: Self (5-foot radius) Components: S Duration: Instantaneous

You create a burst of thunderous sound, which can be heard 100 feet away. Each creature other than you within 5 feet of you must make a Constitution saving throw. On a failed save, the creature takes 1d6 thunder damage.

At Higher Levels. The spell’s damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).

When we are multiclassing, does the overall level of the character effect this, or is it about the individual level of the class that is used to cast this spell?

Can an algorithm complexity be lower than its tight low bound / higher than its tight high bound?

The worst case time complexity of a given algorithm is $ \theta(n^3logn)$ .
Is it possible that the worst time complexity is $ \Omega(n^2)$ ?
Is it possible that the worst time complexity is $ O(n^4)$ ?
The average time complexity is $ O(n^4)$ ?

IMO it is possible as long as you control the constant $ c$ , but then what’s the point of mentioning any other bound than the tight bounds?

Can a Circle of the Stars druid fire an arrow from its star form and cast a spell of 1st level or higher during the same turn?

The druid subclass Circle of the Stars from Unearthed Arcana: Subclasses, Part 3 has the 2nd-level feature Starry Form, part of the description of which states:

You gain a bonus action that you can use to make a ranged spell attack, hurling a luminous arrow that targets a creature you can see within 60 feet of you. On a hit, the attack deals radiant damage equal to 1d8 + your Wisdom modifier.

Does “making a ranged spell attack” count as casting a spell and therefore limit your action to a cantrip or can you cast a spell of first level or higher because the arrow is not a spell? Could I cast one of the freely available Guiding Bolts and fire an arrow or do I have to stick with something like frostbite and an arrow?