stop the merry-go-round

ate a lot, drank a lot, yelled at kids a lot, got food poisoning once, ruined several new articles of clothing, stayed in cool hotels, learned many things about international travel that i plan to forget over the next couple days

Paul White

did you bring back the metric system?

Erik Darling

i'm still unclear on what that is

Paul White

looks like that trace flag might still be effective then

also

> If the plan cost is > CTFP, look at the parallel version of the serial plan

more like

> If the plan cost is > CTFP, find a brand new plan with parallelism as a requirement

erikdarlingdata.com/2019/08/can-dop-change-query-plan-choices

Erik Darling

yes

i think my point was that i misunderstood that

perhaps that's what i sholud clarify

Paul White

2:15 PM

> and not just the parallel version of the serial plan

it doesn't produce a parallel version of the serial plan at any stage, except by coincidence

it literally starts from scratch

Erik Darling

there's an awful lot of coincidences out there

Paul White

yes well people only notice those

and to be fair the chances are quite high

because the optimizer tends to follow a similar path

but still

Erik Darling

creature of habit

Paul White

rules is rules

Erik Darling

had you noticed dm_tran_persistent_version_store before?

like, hidden amongst the symbols

Paul White

2:17 PM

yes that was a new a couple of CTPs back wasn't it?

Erik Darling

don't remember

Paul White

there was a silly procedure originally

Erik Darling

nothing showed up in google

Paul White

I forget the name of it

it was really dumb

Erik Darling

it's showing up as "new" looking from rc1 > ctp3.1

Paul White

2:20 PM

3.2 has

sys.dm_tran_persistent_version_store
sys.dm_tran_persistent_version_store_stats

Erik Darling

dull

Accelerated Database Recovery cannot be enabled until the Persistent Version Store is cleaned of previous versions. Please use the procedure sys.sp_persistent_version_cleanup '%.*ls' to clean the Persistent Version Store.

Accelerated Database Recovery cannot be enabled/disabled on system databases.

poor tempdb

Paul White

The single best thing about PVS is logical reads when traversing a version chain

Erik Darling

Accelerated Database Recovery cannot be enabled while database mirroring is enabled.

ha ha ha

Paul White

ooo

I wonder why

The problem I find with lots of CTPs is that 2019 doesn't seem so exciting anymore

Erik Darling

probably to mess with aws since their availability zones use mirroring

Paul White

2:25 PM

ha! maybe!

Erik Darling

Columnstore index creation is not support in tempdb when memory-optimized metadata mode is enabled.

literally what

Paul White

yeah

there's a trace flag to enable that but it threw assertions all over the show in 3.2

I guess they haven't fixed that yet

Erik Darling

Columnstore index operation failed. Please contact Microsoft customer support.

Paul White

Also who writes those messages

Erik Darling

Paul White

2:28 PM

If you want to try it on RC1 it is 1828

@ErikDarling nice

It does seem like stuff that doesn't work in a Release Candidate is at risk of not making it to RTM

Stating the obvious I suppose

Erik Darling

@PaulWhite session level work?

@ErikDarling no

startup?

yes

dag nabbit

2:34 PM

yeah it's a pain but there you go

Erik Darling

trying to figure out if i'm emotionally available enough to do that rn

looking bleak

Paul White

jet lag

perhaps you've developed an allergy to freedom

Erik Darling

i think it's technically jet lead when you go back in time

Paul White

like the freedom to corrupt your database using start up TFs

is there even a time zone change on such a short flight

Erik Darling

well i'm trying to read this post about batch mode bitmaps

we flew from copenhagen to nyc

it was like 8 hours or something

Paul White

2:38 PM

@ErikDarling that seems unwise after time travel

Erik Darling

i got a check for $3.95 as part of a class action settlement

Paul White

sweet

though the French would say cheque

how quickly it wears off

Erik Darling

chequemate

cheque, mate

Paul White

l'addition s'il vous plait

Erik Darling

i can't wait to go to the gym again

i've gone SOFT

Paul White

2:44 PM

and grey

like a Belgian blancmange

Erik Darling

beard is shaved

Joe Obbish

a long transcript to read

Erik Darling

> If the estimated selectivity of the semi join is 0.75 or less, the optimizer considers it worthwhile using a batch mode bitmap filter

Joe Obbish

finally

Erik Darling

does row mode use a similar doodad?

Paul White

2:45 PM

Erik is massively verbose

@ErikDarling don't recall

probably

would be easy to cheque

Erik Darling

i don't believe you

this must be spicy

muy caliente, as they say

Paul White

In Europe?

YOU HAD A WHOLE MONTH

Erik Darling

GRANDE CHAUD

Joe Obbish

ok

Erik Darling

oh i found it funny that froid is cold

Joe Obbish

2:48 PM

the transcript was full of nonsense

Paul White

bon mot

Erik Darling

gott strafe joe

Paul White

@ErikDarling froid is the new hotness

Joe Obbish

my main issue with froid is that it's going to spawn thousands of terrible presentations

Paul White

and pissy complaints

Joe Obbish

2:49 PM

I don't know any SQL Server complainers

is that a common thing?

Erik Darling

have you seen twitter

Paul White

there Internet is full of them

they all have blogs

Joe Obbish

~I~ don't have a blog

Paul White

Is that a complaint?

Joe Obbish

chequemate

Paul White

2:50 PM

en passant

Seriously though the first person to post "Froid made my functions slower" gets blacklisted

Joe Obbish

blacklisted from what?

and I thought Erik already did that

Paul White

all good things

I think it was Brent

also my rule only applies to people who couldn't squish me like a bug

if they weren't so old and grey, obv.

Joe Obbish

is it acceptable to complain after RTM?

Paul White

yes just not in a massively tedious way

like try to be a bit original and non-obvious

though complaining after RTM will lead to "all fixed in 2021"

so idk

Joe Obbish

that's what I do best

Paul White

3:00 PM

play to your strengths then

my advice is for non-room people

has Erik gone on holiday again?

Joe Obbish

I want to go on a mental holiday

do you need drugs for that?

Paul White

well getting hit by a bus might lead to a medically-induced coma

but drugs are a relatively low-risk alternative

depending on the chemical of choice

I hear lysergic acid diethylamide is making a comeback

Joe Obbish

sounds scientific

Paul White

everyone was a scientist in the 70s

Erik Darling

@PaulWhite apparently kids have gotten used to me spending time with them

vacation was a mistake

Paul White

3:13 PM

holidays are more expensive than they seem

Joe Obbish

@PaulWhite just think about how high Erik's AC bill is

Paul White

hm true

I bet he left it running though

Erik Darling

on energy saver

Paul White

very green

Joe Obbish

what happened to the protest against government overreach?

Erik Darling

3:18 PM

went too far

Joe Obbish

I hope you can accept the guilt when your children have to always run their AC at 78

that'll be the legacy of your generation

Erik Darling

i raise rebels

is 78 even air conditioning?

that seems like the most uncomfortable possible temperature

Joe Obbish

depends on the humidity

@ErikDarling got a moment to respond to a really shitty email?

Erik Darling

yes

when should i expect it?

and who is it shitty for?

Joe Obbish

@ErikDarling me

@ErikDarling now

Erik Darling

3:50 PM

@PaulWhite the companion post is way cooler

Joe Obbish

@ErikDarling go to www.sql.kiwi for the REAL SQL performance?

Erik Darling

i bet it'll make a newsletter

Paul White

8:33 PM

@ErikDarling because it has pictures and code?

Erik Darling

8:52 PM

@PaulWhite it's more technical, imho

Paul White

Ok thanks

Erik Darling

10:16 PM

well plus your site is much more handsome

i dunno, it's a good companion piece

just put the a/c down to 62

both of them

>>>devilish

Transcript for

♦ stop the merry-go-round