Arjun Mehta
Backend engineer at a lending startup in Bengaluru. Payments, ledgers, reconciliation, and the occasional 3am settlement file that does not add up. Postgres fan. Will talk about idempotency keys until you leave.
- 12
- 13
- 2.4K
- 293
Posts
Everything this author has published.
Best answers
Accepted answer
rust: cannot borrow `*self` as mutable because it is also borrowed as immutable
Classic one. The loop holds a borrow of self.items, and update wants all of self mutably, which includes items. A few normal fixes: 1. Make update not take…
Accepted answer
UK SaaS selling to EU customers: do i need to register for VAT there from the first sale?
Not tax advice, but this is the part people mix up. The €10,000 threshold is only for businesses established inside the EU. As a UK seller after Brexit you are…
Accepted answer
Django REST Framework: still N+1 queries after select_related, what am I missing?
select_related only follows ForeignKey and OneToOne, with a JOIN. Your 2 extra queries per row are the tags (ManyToMany) and the count. Do this: queryset =…
Accepted answer
Postgres count(distinct) on 80M rows very slow, any trick?
count(distinct) in Postgres sorts the input for each group, it cannot use a hash aggregate. Rewrite so the distinct happens in a subquery, then the planner can…
Answer people found useful
Daily sales report across timezones: which day does an order at 11:30pm Bangkok belong to?
We do both, explicitly. Store the market timezone on the order (or on a markets table) and compute business_date = (created_at at time zone market_tz)::date.…
Answer people found useful
Contract testing across 12 services: is Pact worth it or overkill?
We did Pact for payment flows between 5 services. It worked because we started with only the 2 integrations that broke most often, not everything at once. Few…
Links
Where else to find this person.
Badges earned
Strongest tier first.
Century
SilverReached 100 reputation points.
Earned Oct 14, 2026
Well Received
SilverYour posts have collected fifty likes between them.
Earned Sep 26, 2026
Generalist
SilverPublished in three different topics.
Earned Sep 8, 2026
Problem Solver
SilverAn answer you wrote was accepted by the person who asked.
Earned Aug 24, 2026
Regular
SilverPublished ten posts. Showing up is most of it.
Earned Aug 10, 2026
Settling In
BronzeA month since you joined.
Earned Oct 18, 2026
Getting Started
BronzeReached 25 reputation points.
Earned Oct 10, 2026
First Readers
BronzeYour posts have been read a hundred times.
Earned Oct 6, 2026
Worth Keeping
BronzeSomebody saved one of your posts to read again.
Earned Oct 3, 2026
Quotable
BronzeYour comments have earned ten likes.
Earned Oct 1, 2026
First Applause
BronzeSomebody liked something you wrote.
Earned Sep 24, 2026
Someone’s Listening
BronzeSomeone followed you for the first time.
Earned Sep 18, 2026
Finding People
BronzeFollowing five people. Enough for a feed with something in it.
Earned Sep 13, 2026
Explorer
BronzeJoined five topics and settled into the community.
Earned Sep 1, 2026
Straw Poll
BronzeCreated your first poll and asked the community to decide.
Earned Aug 28, 2026
Curious
BronzeAsked your first question. Nobody starts out knowing.
Earned Aug 22, 2026
Said Hello
BronzeLeft your first comment on somebody else’s post.
Earned Aug 12, 2026
First Post
BronzePublished your first post on Dynamo Geeks.
Earned Jul 30, 2026