anarazel

21 ms·

211.
by anarazel 3y ago
The TLB is basically keyed by (address space, virtual address % granularity), or needs to be flushed entirely when switching between different views of the address space (e.g. switching between processes). Unless your address space is exact
212.
by anarazel 3y ago
pgbouncer is not transparent, you loose features, particularly when using the pooling mode actually allowing a larger number of active concurrent connections. Solving those issues is a lot easier with threads than with processes.
213.
by anarazel 3y ago
I'm not sure if I'd judge it as harshly, but you have a good point: A lot of debugging / validation tooling understands threads, but not memory shared between processes.
214.
by anarazel 3y ago
Because it makes it a lot easier to address some of postgres' weaknesses? This is a proposal by long time contributor to postgres, that a number of other long time contributors agree with (and others disagree with!). Why shouldn'
215.
by anarazel 3y ago
> That said, many of these things are solvable without a full switch to a threaded model (eg. by having pooling built-in and session-state-aware). The thing is that that's a lot easier with threads. Much of the session state lives i
216.
by anarazel 3y ago
Heikki is far from the only "senior" postgres contributor thinking that this is the right direction in the long term. > You're just defending your hero who has gone rogue. That doesn't sound like judging an idea on it
217.
by anarazel 3y ago
> Like light-threads, heavy-threads would share the same process-security-boundary and therefore switching between them would be cheap. No need to flush TLB, I$, D$. > Like processes, heavy-threads would have mostly-separate address s
218.
by anarazel 3y ago
We would still have a separate supervisor process of we moved connections to threads.
219.
by anarazel 3y ago
Postgres already shares a lot of state between processes via shared memory. There's not a whole lot that would initially change from a concurrency perspective.
220.
by anarazel 3y ago
Postgres is already concurrent today. There's a lot of shared state between the processes (via shared memory).
221.
by anarazel 3y ago
We would still have a separate process doing that part of postmaster's work.
222.
by anarazel 3y ago
> Apologies autocorrect substituted Moor for Lane. > > But I believe you knew that but pedantry stopped you from just suggesting it. I was wondering about it, but thought it wouldn't really make sense, given that Tom was the
223.
by anarazel 3y ago
> I saw a bunch of nays and a lot of “abstains” a lack of vote against something is not a vote of approval. There's definitely some ayes, including the people mentioned in the post upthread. > Basically Postgres loses 10% perfor
224.
by anarazel 3y ago
It worked like this for much longer. The oldest version I have around is 9.2 and it behaves the same. You probably are thinking of a somewhat more complex scenario...
225.
by anarazel 3y ago
> Msbuild isn't too bad once you've got over the culture shock that (a) everything is XML rather than tab-delimited makefiles and (b) you've got a glossary of terms that maps to things you know https://learn.mic
226.
by anarazel 3y ago
I liked Tegel. The low distances between entrance and all the gates, combined with the per-gate security, allowed to arrive much closer to the departure time than at other airports, IME. I never checked luggage flying via Tegel tho.
227.
by anarazel 3y ago
Forgot to say: Obviously a partial index is going to be considerably better, performance and size wise.
228.
by anarazel 3y ago
> My recollection in postgres anyway is that low cardinality indexes aren't useful, because it doesn't take into account which side of the 1/99% you're on when determining to use the index. It does take that into acco
229.
by anarazel 3y ago
Yeah- we've been working on that for quite a while, and it'll take a few more years to finish it. I hope we can get some important parts into 17 though. FWIW, there have been smaller prerequisites merged into 15 already, and 16 h
230.
by anarazel 3y ago
If it were easy to do well in-core, I think we'd do it immediately. Unfortunately the interesting pooling modes in pgbouncer also break a few things - which would likely not be acceptable in core postgres. Avoiding such breakage requir
231.
by anarazel 3y ago
I'm sure there's a rate of concurrent writes where that wouldn't be true anymore, but if so, you're likely not going to be benefiting that much from the approach to caching.
232.
by anarazel 3y ago
> PG 11 is end-of-life, right? So you won't be getting new security updates. Not quite yet https://www.postgresql.org/support/versioning/ - the final release will be November 9, 2023.
233.
by anarazel 3y ago
> I also don't see anyone claiming they can saturate their network interface with postgres the same way they can with any KV store. I recently tested it, and I could trivially saturate a 10GBit interface with postgres. https:/
234.
by anarazel 4y ago
I think that's often fixed using a per run random seed, rather than a per table seed. The patch linked in the python bug linked from that article does seem to do that, for example.
235.
by anarazel 4y ago
One situation where I painfully learned that it doesn't, is when you iterate over one hashtable to fill another. To defend against that one needs to add some per-hashtable randomized state into the hash IV. Through bad experience I als
236.
by anarazel 4y ago
Sorry, I should have used something more standard - but it was what I had ready... It just selects every column from a single table, pg_class. Which is where postgres stores information about relations that exist in the current database.
237.
by anarazel 4y ago
I agree that redis can handle some query volumes and client counts that postgres can't. But FWIW I can easily saturate a 10GBit ethernet link with primary key-lookup read-only queries, without the results being ridiculously wide or any
238.
by anarazel 4y ago
CREATE DOMAIN unsigned_64bit_int AS numeric CONSTRAINT range CHECK (VALUE >= 0 AND VALUE < 2^64 AND round(VALUE) = VALUE);
239.
by anarazel 4y ago
> I suppose you reduce the blast radius a little for memory corruption issues when programming in something like C, but these days if you are using a type safe language I'm not convinced it buys you much in terms of fault tolerance.
240.
by anarazel 4y ago
It's just a clientside knob for psql. You can do something like it in any client.

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