MongoDB 1.8 (stable) released • Hacker News Board

Re: MongoDB 1.8 (stable) released

#61

Post by crux_ » Thu, Mar 17, 2011, 4:29 PM UTC

thibaut_barrere wrote: post #59

crux_ wrote: post #58

Earlier quoted context omitted.

The problem I have is at least partly one of truth in advertising. For example: If they were truly using a "spherical model", then one would not expect to have queries fail at the poles & dateline, would you? At least it is documented and fails hard with an error rather than giving wrong results, so a developer can quickly figure out the weak spots --- though I bet a lot of people would prefer the wrong results to qu…

I don't know really - if limitations are documented like they are apparently, it's really not an issue for me - I don't feel cheated (but it's really an opinion!). Your mileage may vary as they say: I used the GIS since 1.6 and it was very helpful for me in this form already :)

The limitations are documented as foot/side notes.

Analogy: It's like seeing "ACID compliance!" on a feature list, then finding buried in the documentation that is only the case for single-document transactions in unordered collections on a single machine only.

The new feature might be useful to some but including it on a feature list without disclaimer is misleading.

Re: MongoDB 1.8 (stable) released

#62

Post by mrinterweb » Thu, Mar 17, 2011, 4:48 PM UTC

kchodorow wrote: post #57

mrinterweb wrote: post #46

Earlier quoted context omitted.

I got in so much trouble for a very similar web scale comment. Never shall trite jokes be used on hacker news. You'll get your head bit off. Personally, it gives me a giggle, and I guess that means I am much less mature than most consumers of Hacker News. http://news.ycombinator.com/item?id=2104276

I think it's just an old joke at this point. It's funny the first time you see it and the second time, but the 50th?

I did admit the joke is trite.

Re: MongoDB 1.8 (stable) released

#63

Post by vegai » Thu, Mar 17, 2011, 4:50 PM UTC

vegai wrote: post #51

The clustrix guy criticized mongodb that it locks the whole database quite often. Can anyone confirm or deny that?

Modded to 0 and never answered. I'll take that as a confirmation.

Re: MongoDB 1.8 (stable) released

#64

Post by JulianMorrison » Thu, Mar 17, 2011, 5:11 PM UTC

phsr wrote: post #40

As a newb to non-relational databases, but planning on learning one soon, what is the advantage of MongoDB vs Redis? I'm planning to use ruby with either, but was interested if there was a reason to pick one over the other.

Redis is for flat structures. MongoDB is for nested.

In both cases, (unlike CouchDB) you can alter data structures by more complex means than simply replacing the whole thing (such as incrementing a counter). In both (again unlike CouchDB) the updates overwrite in place and do not waste space (but also do not preserve past versions or allow readers to overlap writers).

Redis is for stuff that fits in memory. MongoDB scales up to "big data", provided the individual items are moderately sized.

Redis runs in RAM so it's blazingly fast. MongoDB is about as fast as MySQL.

Redis is single threaded so only one operation runs at once (the speed makes this mostly not a problem). Some operations globally block MongoDB, some can run in parallel.

In both, operations are atomic. Redis has transactions of a sort that group operations and ensure the data they relate to is unchanged. MongoDB operations can't be grouped into a transaction, but they can be a lot more complex so they effectively become a transaction (limited to operating on one data item).

Re: MongoDB 1.8 (stable) released

#65

Post by thibaut_barrere » Thu, Mar 17, 2011, 5:46 PM UTC

crux_ wrote: post #61

thibaut_barrere wrote: post #59

Earlier quoted context omitted.

I don't know really - if limitations are documented like they are apparently, it's really not an issue for me - I don't feel cheated (but it's really an opinion!). Your mileage may vary as they say: I used the GIS since 1.6 and it was very helpful for me in this form already :)

The limitations are documented as foot/side notes. Analogy: It's like seeing "ACID compliance!" on a feature list, then finding buried in the documentation that is only the case for single-document transactions in unordered collections on a single machine only. The new feature might be useful to some but including it on a feature list without disclaimer is misleading.

I understand your analogy really :)

Really curious: are you using mongo currently? Or browsing the docs?

Re: MongoDB 1.8 (stable) released

#66

Post by eldenbishop » Thu, Mar 17, 2011, 6:29 PM UTC

Wow. I knew about the durability changes but I had no idea that sparse and covered indexes where coming. These three changes where the biggest drawbacks to mongo for me.

Re: MongoDB 1.8 (stable) released

#67

Post by crux_ » Thu, Mar 17, 2011, 6:45 PM UTC

thibaut_barrere wrote: post #65

crux_ wrote: post #61

Earlier quoted context omitted.

The limitations are documented as foot/side notes. Analogy: It's like seeing "ACID compliance!" on a feature list, then finding buried in the documentation that is only the case for single-document transactions in unordered collections on a single machine only. The new feature might be useful to some but including it on a feature list without disclaimer is misleading.

I understand your analogy really :) Really curious: are you using mongo currently? Or browsing the docs?

I'm not using it directly, but sometimes I use tools that in turn use mongo. -- So for now, browsing docs.

Re: MongoDB 1.8 (stable) released

#68

Post by joegester » Thu, Mar 17, 2011, 7:20 PM UTC

davidw wrote: post #9

MongoDB is not something I have a good handle on yet. What's its sweet spot? Where should I consider using it instead of Postgres?

My experience has been that many applications (web apps in particular) use a relational database to break up documents into an SQL schema so they can be indexed, then assemble them again when needed. Mongo really ratchets down the friction on that operation. Instead of spending time building a schema and writing lots and lots of insert and update statements, you just build a JSON object and send it over.

Re: MongoDB 1.8 (stable) released

#69

Post by joelhaasnoot » Thu, Mar 17, 2011, 8:41 PM UTC

joelhaasnoot wrote: post #31

dstorrs wrote: post #28

Could someone with Mongo experience help me gut-check this? I want my data store to be durable and unsurprising -- barring a hardware failure or such, if I submit data it should either tell me that it failed to commit or it should be stored durably and without surprises (e.g., it should not truncate a long string to fit). I've read some of the Mongo docco, and it's pretty exciting, but the lack of ACID -- primarily t…

Don't know, I'm going to be testing this tomorrow, but came to work today to a server that was grinding to a halt due to wild running node.js processes. Restarted the server, but that doesn't cleanly shutdown Mongo, and spent an hour repairing everything and setting permissions right (somehow they had gotten reset). This exact problem, so hope the --journal switch in the init file makes the difference.

Added "journal = true" to the config and it certainly stops and starts the service nicely now. No more repairs and such, my data is currently query only, so it's mainly "optical", cleaning up locks and such.