Debugging the Postgres query planner (2018)

I know what you mean, but I don't think that that quite captures it. It's more like this: planners are built on a set of assumptions that are often pretty far from robust, but nevertheless work adequately well in almost all cases. Including many cases where the assumptions haven't been met!

The best example is the standard assumption that multiple conditions/columns are independent of each other -- all optimizers make this assumption (some can be coxed into recognizing specific exceptions). This is obviously not true much of the time, even with a well normalized schema. Because: why would it be?

All kinds of correlations naturally appear in real data. It's just that it mostly doesn't cause huge problems most of the time, for messy reasons that can't quite be pinned down. You have to get unlucky; the correlations usually have to be very high, and the planner makes completely the wrong inference for the actual query that you ran (not some hypothetical other query). The planner only has to have approximately the right idea to discover the cheapest plan. And the planner doesn't have to discover the cheapest plan in many cases -- there may be quite a few adequate plans (it's really hard to generalize, but that's often true).

Overall, the fact that cost-based optimizers work as well as they do seems quite surprising to me.

However do you make it that I have claimed that a Oracle license would make your team redundant?

I certainly didn't suggest anything like that.

But please forgive me for being reflexive, has your response accidentally been more revealing than intended about duplicating technologies that isn't AS clear as it might be from the context?

Nobody gets to let go any good database team this side of sanity for whatever reason.

Nevertheless I didn't phrase my comment as thoroughly as I probably should have:

"Working safely with" any asset class data store just shouldn't ever be a question without immediate answers. On going development for the same pirates, doesn't provide executive management with solid answers to "define safety issues present future and potentially retrospectively debugging any failure".

10TB primary dataset isn't considerable amount of production in valuable chain scale of store. Default not a large database on any Oracle installation.

DBMSs require administrative rigors and procedures as well as ideally in depth theory of operations and definitely codebase development skills with the engineering and management system itself is extremely desirable.

However, I can't help thinking that here is a potential case of taking those undoubted talents to directly create proprietary variants of Postgres, which is only going to develop technical debts and future increase in nominally normative support costs.

In other words, I think that your talents have been inappropriately unleashed. You're brain surgeons and everything looks like a brain to you?

Unfortunately and obviously the mere mention of Oracle is liable to create greater difficulty in the creation of openly equitable technical discussions. Oracle management managed to perfect this awful disassociation effect I'm convinced purely for stress testing potential customers often in a gaighting style / hazing sales process . Check out the lady Oracle sales executive who files suit in California every year just to try and negotiate payments of some approximate order to her contractual commission deal. Not many smaller companies get much beyond that not inconsiderable corporate culture clash. I used to joke that Oracle sales cycles were a super proving ground for whether you have a growth business model or not. Because account growth is the keys to sales commissions and simultaneously your easiest leverage for getting big discounts. (Start from 50% before anyone says anything, kept our business afloat)

Ultimately I am unable to understand the point you're making, because you claim inseparable effects from tangential issues and not the smallest misrepresentation of my argument.

Being pedantic, neither of us ought to have used the word "purchase" in relation to licensing nigh inseparable from support and other fat margins. You can still buy a per socket license for RDB , however, and obtain the x64 40% socket discount if you can get VMS X64 running. Sometime soon I'm going to risk indicating that we've renewed interest in such a installation.

The problem I have with the engineering path you took is merely that for the scale and growth outlined, off the shelf solutions absolutely exist and some are thoroughly honed for optimal low administration and even lights out running. We're all potentially caught up in the limitations of early start up scaling of essential computer services, when ad hoc OSS wrangling definitely can sound more attractive than months failing to even understand the small talk spoken by the whole freaking teams turning up to sell you big company shrink wrap software. I'm going round this once again, and have cut myself the budget for dumping all non novel problems onto the most tried solutions. In other end, being ruthless to only spend engineering resources on strategic advantage absolutely can encompass a large license deal or two, but ironically whilst wanting to get rid of Oracle (together with historical deployment and tuning sins) is just that much more attractive a fictional moral campaign than holy war against teaching development teams about transactions on payroll. I'm cynical indeed, but I hope the circumstances are more clear now?