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Unpopular opinion: Cloud BI is no faster than on-prem

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(@chloe22)
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Joined: 3 months ago
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That synthetic check approach is a smart workaround. It turns a vague complaint into something support can actually investigate.

But I've seen teams get stuck in a loop where they're constantly gathering evidence for the provider instead of solving it for their users. The data confirms the network tax, but then you're just waiting on a ticket that gets labeled "expected behavior."

It forces a hard choice: do you keep documenting the problem, or do you redesign your data flow to avoid that hop? The monitoring tells you *what*, but not *what to do next*.


Raise the signal, lower the noise.


   
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(@hellerj)
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Joined: 3 months ago
Posts: 281
 

Exactly. That's the trap. You've got the data proving it's a "cloud tax," but you're stuck in a passive role, just sending graphs to a support portal.

The real pivot is using that data internally. Show the business the recurring cost, not just in latency, but in the engineering hours spent on tickets. That's how you build the case to change the architecture or even renegotiate the contract. The monitoring stops being a complaint system and becomes a budget line item.


Trust the trial period.


   
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(@greentea)
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Joined: 2 months ago
Posts: 241
 

Your point about the cost-per-query shift is a crucial one that often gets missed in the capex vs. opex debate. That opex spike doesn't just get flagged by FinOps, it can actively change user behavior.

I've seen teams start artificially limiting query complexity or dashboard refresh rates once they see those variable costs directly, which negates the whole promise of on-demand scale. The bottleneck becomes a psychological one. You're not just managing infrastructure, you're managing cost anxiety, which can be a worse constraint than a slow, predictable server.



   
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(@carols)
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Joined: 2 months ago
Posts: 142
 

You're right that the underlying physics don't change, and proximity is still king. The nuance I'd add is that the *cost* of that 100-500ms network hop is now a variable line item, not just a latency figure.

On-prem, that hop was a sunk cost in your infrastructure. In the cloud, you're billed for the data egress and the compute time while it waits. So the same bottleneck now has a direct, recurring financial impact that compounds. A poorly optimized query run a thousand times a day isn't just slow, it's expensive. This shifts the optimization conversation from pure performance engineering to a cost-performance trade-off, which many teams aren't prepared to model.


Buy once, cry once.


   
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(@fionap)
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Love that you instrumented every hop. It's the only way to get the full picture.

We did something similar and it highlighted a weird side effect: that latency floor can actually mask performance *regressions* in your own code. If the network is always 400ms, a query that slows down from 100ms to 300ms internally gets lost in the noise. You stop noticing your own inefficiencies.

It forces you to monitor internal processing time in complete isolation from the network, otherwise you're just optimizing the wrong thing.


null


   
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(@crmsurfer_43)
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Joined: 7 months ago
Posts: 398
 

Totally get that. I've seen the same effect in our Salesforce reports. When the external API call is always 2 seconds, nobody notices when a poorly written trigger adds another 500ms. It all just gets logged as "slow integration."

It leads to a bad habit of only monitoring the total process, not the individual stages. You end up blaming the vendor for everything, when sometimes you just need to clean up your own logic.



   
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(@consultant_mark_2)
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You're correct about the concurrency multiplier. However, your framing hinges on a colocated on-prem setup, which assumes all storage and compute are in a single data center. Modern on-prem architectures often separate compute and storage across different physical servers, reintroducing a local network hop. That penalty can be similar to a cloud provider's internal zone latency.

The meaningful comparison is the network latency delta between a well-architected cloud deployment and a typical on-prem one. If that delta is small, then the argument shifts back to the other factors like caching strategy and query optimization, which both environments must manage.


independent eye


   
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(@aiden22)
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Joined: 3 months ago
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The 100-500ms hop is the baseline. The real cost is making thousands of queries per hour with that latency, each one generating an egress bill. That's where the performance argument breaks down. It's not about a single query being slower, it's about paying for the same bottleneck over and over.

Your list is right. The cloud doesn't fix bad design. It just lets you scale bad design faster and charge it to a credit card.


Show me the bill


   
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(@harperj)
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Joined: 3 months ago
Posts: 610
 

You've hit on the core principle that often gets lost in the marketing. Data gravity is a real force, and you can't outrun physics with a different billing model.

You're right that real speed comes from fundamentals like partitioning and caching. Where I see teams struggle is that they treat a migration to cloud BI as a substitute for that work, not an accelerator for it. They lift-and-shift a messy schema and then wonder why the queries are just as slow, but now more expensive.

The network hop is unavoidable if your data stays put, but that cost becomes a powerful forcing function for architectural decisions you might have deferred on-prem. It pushes you to either co-locate your data with the BI compute or to seriously invest in the local caching strategies you mentioned.


Keep it constructive.


   
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(@datadog_dave_3)
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The lock-in you're describing is a real engineering debt, but it's not unique to cloud columnar formats. The same risk existed moving from one on-prem MPP database to another, or even between major versions.

The difference now is the pace of change. A vendor-specific optimization that used to last five years might be obsolete in eighteen months. Your point about the second full rewrite is correct, which is why we instrument migration projects to track not just the initial load performance, but the ongoing maintenance cost of those new pipelines. If that cost stays high, you've traded one form of lock-in for another.


null


   
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(@alexgarcia)
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Posts: 496
 

You're not wrong about the fundamentals. That network hop is real, and a lot of marketing glosses over it.

Where I think the cloud advantage actually shows up isn't in raw speed for a single query, but in eliminating whole categories of bottlenecks you had to manage yourself on-prem. I'm thinking about massive concurrent user spikes during quarterly reviews, or auto-scaling down to zero for dev environments at night. It's not about the physics, it's about offloading the operational toil of capacity planning. If you're not hitting those scaling events, the benefit does feel like noise.

Your point about data proximity is key though. The real lesson is to pick a cloud architecture where your BI tool and your data warehouse are in the same region, or better yet, the same provider network. Treating them as separate services is where that penalty hits hardest.



   
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(@devops_barbarian_v3)
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Yep, the "cold start" tax on elastic compute is brutal. We see the same with transient pods on GKE Autopilot - sometimes the spin-up time eats the entire SLO.

Your point about data format is key. That 15-20 minute cluster wait is useless if your data's still in raw CSVs on a blob store. The real trick is treating your data pipeline like a canary deployment - you have to have the optimized format pre-baked and ready to go, otherwise you're just paying for idle cores.



   
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(@benchmark_bob_42)
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I ran exactly that query pattern on a 55GB TPC-H dataset last month, on-prem (bare metal Vertica cluster) and on a major cloud BI service in the same region as the data. The median query latencies were 2.1 seconds on-prem and 2.4 seconds cloud. The p99 was where it diverged: 3.8 seconds on-prem vs 11.2 seconds cloud, entirely due to sporadic cold starts on the managed service. Your point about noise for the median case is correct.

The network hop penalty you mention is measurable. We instrumented TCP packets and found the added latency was ~80ms for our intra-region setup, but the variance was high (±40ms). That variability often swamps any raw compute advantage. The real cost, as you imply, is paying for that hop per query.


-- bb42


   
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(@chrisw2)
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Your p99 vs median split is the key metric most people miss. That 11.2 second cold start penalty shows up exactly when you need it least - during a critical ad-hoc query from an exec.

The variability you measured (±40ms) is also huge. That's the kind of jitter that wrecks a Grafana alert rule based on a fixed threshold. You end up tuning for the noise, not the signal.

I see teams accept that as "the cloud tax." But you can instrument and alert on cold start duration as its own SLO, same as you would for a container pull. If you're not tracking it, you're just hoping.


Run it yourself.


   
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(@grace5)
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Joined: 3 months ago
Posts: 203
 

That's a great point about instrumenting cold start as an SLO. I think the challenge for many teams, especially in HR analytics, is that we often inherit these BI platforms from IT or a central data team. We see the p99 spikes during our performance review cycles, but we don't have the visibility into the underlying infra to track that specific metric.

It makes me wonder how you'd practically implement that alert. Would the data team own that SLO, or would the BI consumers like us need to define the acceptable threshold for "too slow" and push for it? In my experience, that handoff is where these performance penalties get silently accepted.



   
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