If a DB table is 3TB in size and read speed is 10mbyte/sec. Does it mean that 83hours are necessary to create new index?

One of our custom log tables is 3TB in size. We need to create a new index. Read speed on the disk itself is 10mbyte/sec.

Does this mean that the index creation process will be 3.000.000/10 = 86 hours? The index is written to another filegroup on a fast disk so write time is not a factor.

If there is mandatory participation between 2 entities in an ERD, does this mean neither of them are strong entities?

Say I have entity A with primary key "key_A" and entity B with primary key "key_B”. I also have that key_A is a foreign key in entity B. My business rules state that every instance of A is related to at least 1 instance of B, and every instance of B is related to exactly 1 instance of A. In a situation like this, how would you classify A and B as weak/strong entities?

Linear regression: confidence interval of the average of 10 slopes, error of propagation and error of the mean

I have 10 regression slopes in one group, each slope has its associated standard error. Now I want to find the average slope of this group and the associated standard error which will be used to find the 95% confidence interval. I know the standard error of the mean is the sum of the squared deviation from the mean divided by the square root of the sample size and the sample size is 10 in this case. I can calculate the average slope and find the deviation of each slope by subtracting the mean. But since each slope has an associated standard error, how do I take into account of this when I calculate the standard error of the mean or actually I don’t need include the error from each slope?

For the confidence range of the average slope of this group, I am using 1.96*standard error of the mean.

Your help will be much appreciated!

What does the Swarmkeeper mean by “horizontal”?

The Ranger Swarmkeeper Gathered Swarm has 2 ability’s that can force horizontal movement. But how do they work?

The attack’s target must succeed on a Strength saving throw against your spell save DC or be moved by the swarm up to 15 feet horizontally in a direction of your choice

Is this horizontal from the direction I am facing, and if so what is stoping me from turning myself to aim freely, or is it horizontal from where the monster is facing? And second we have…

You are moved by the swarm 5 feet horizontally in a direction of your choice.

What’s stopping me again from changing my direction to move freely here too?

What does this the DH 2e’s Mountain Warrior’s ‘each advance’ mean?

Mounted Warrior

Requirements: Rank 2 (Trained) in any Operate skill or Rank> 2(Trained) in Survival skill, BS 30 or WS 30

Apptitude 1 Weapon Skill / Ballistic Skill

Aptitude 2 Offence

Reduces any penalty for making attacks (Melee or Ranged) from a moving vehicle or mount by 10 for each advance.

I’ve not been able to other sources use similar wordings. Does this mean each rank in all operate and survivor skills gives a +10? Is it just the highest ranked of the 4 skills? Or is it something else?

Pact of the Chain, Sprite Familiar. What does it mean that a “saving throw result is 5 or lower”?

I’ve been looking into the warlocks Pact of the Chain, which states that your allowed to pick from the normal familiars as well as a select few Warlock-Only familiars, including the Sprite.

When you cast the spell, you can choose one of the normal forms for your familiar or one of the following special forms: imp, pseudodragon, quasit, or sprite.

Then invocation Investment of the Chain Master states that:

If the familiar forces a creature to make a saving throw, it uses your spell save DC.

And the Sprite has a Shortbow attack that forces a creature to make a saving throw:

Shortbow. Ranged Weapon Attack: +6 to hit, range 40/160 ft., one target. Hit: 1 piercing damage, and the target must succeed on a DC 10 Constitution saving throw or become poisoned for 1 minute. If its saving throw result is 5 or lower, the poisoned target falls unconscious for the same duration, or until it takes damage or another creature takes an action to shake it awake.

From what I gather that means that the initial save for the poison should use the players save DC? So for a lvl 7 character with 20 charisma, that would be a save of 16?

Spell save DC = 8 + your proficiency bonus + your Spellcasting modifier

However the second part of the Shortbow attack states that:

If its saving throw result is 5 or lower, the poisoned target falls unconscious for the same duration

What does "saving throw result is 5 or lower" mean? Would that be the rolled number for the save + the save modifier?

saving throw result = save dice roll + save score modifier

Or would it be the resulting rest from removing the spell save DC from the rolled total?

saving throw result = Spell save DC – (save dice roll + save score modifier)

I haven’t seen the phrase "saving throw result" referring to a number before, usually it just refers to "did the creature roll over or under the spell save DC? Yes or No."

What does svirfnebli mean, and how is it different to svirfneblin?

A recent answer to a question has led me to obtain an e-book for The Dark Elf Trilogy, and the section I am reading uses the word svirfnebli as well as svirfneblin, but I am unsure if it is a printing issue (or possibly a scanning issue) or an actual word, and I can’t really tell why is it different from svirfneblin.


When the svirfneblin guards ushered him in

Scores of svirfnebli rushed about their posts

Both seem to be referring to multiple deep gnomes, so I am unsure, but this is the first time I have read the word svirfnebli, and it is used multiple times in the short part of the book I have read so far. Does anyone know what it means and how it should be used?

If possible, I would like to know if the use of the words have changed through the editions, maybe in 3rd edition they both had a use and it was simplified for more recent editions?

What does the entry 3/day mean if several spell-like/psi-like abilities are listed?

I am preparing an encounter involving a psionic Yuan-Ti Abomination. The entry in the XPH lists under the section psi-like abilities:

3/day—body purification (6 points*), psionic charm (all targets, 1 day/level, DC 19*), concealing amorpha, deeper darkness, mind thrust (ML 7th, 7d10, DC 18*), psionic suggestion (four targets, DC 16*); (XPH, p. 218)

Does that mean the Yuan-Ti can manifest

a) each psi-like ability listed here 3/day,

b) a total of three manifestations of abilities in this list, including using the possibility to use one ability three times

c) three abilites out of this list once each

A similar issue arises with the spell-like abilities in the gnome entry in PHB, where it says:

1/day—dancing lights, ghost sound, prestidigitation.

Does this mean gnomes can use each of these abilities once, or only one of these?