Migrating Messenger storage to optimize performance • Hacker News Board

Re: Migrating Messenger storage to optimize performance

#21

Post by dang » Tue, Jun 26, 2018, 10:02 PM UTC

mtgx wrote: post #6

bigato wrote: post #5

What about giving me an easy option to export my messages while you are at it?

Unfortunately, the feature to export your messages is only available to Facebook's data partners.

This sort of shallow dismissal does nobody on any side of any argument any good.

We've asked you many times to stop posting unsubstantive comments to HN. If you can't or won't stop, we will ban you.

https://news.ycombinator.com/newsguidelines.html

Re: Migrating Messenger storage to optimize performance

#22

Post by Zaheer » Tue, Jun 26, 2018, 11:30 PM UTC

During the dual-write phase, what happens if one request succeeds while the other doesn't?

Re: Migrating Messenger storage to optimize performance

#23

Post by wenc » Tue, Jun 26, 2018, 11:46 PM UTC

tomnipotent wrote: post #2

TL;DR - Moved from HBase to MyRocks engine on MySQL sitting on top of NVMe storage via their Lightning Server [1], which is a JBOF (just a bunch of flash) setup using x16 PCIe. [1] https://code.facebook.com/posts/989638804458007/introducing-...

Anyone know why Facebook moved off HBase? (article doesn't address this)

I get that MyRocks is truly amazing, but I'm wondering what issues they were facing with HBase. I heard HBase was picked over Cassandra (developed at FB) because it was strongly consistent vs Cassandra's eventual consistency.

Re: Migrating Messenger storage to optimize performance

#24

Post by wenc » Tue, Jun 26, 2018, 11:53 PM UTC

jensvdh wrote: post #18

godelmachine wrote: post #9

Earlier quoted context omitted.

Have they published a paper on this on Facebook Research?

Social media apps have "Research" now?

They have a very strong research arm covering a significant number of research areas. https://research.fb.com/

Re: Migrating Messenger storage to optimize performance

#25

Post by nemothekid » Wed, Jun 27, 2018, 12:03 AM UTC

Facebook has been using RocksDB more and more (now messenger, but also Instragram’s flavor of Cassandra). I wonder if Google has a similar penetration of LevelDB (and we just don’t hear about it because Google’s infrastructure work isn’t open source)

Re: Migrating Messenger storage to optimize performance

#26

Post by asfasgasg » Wed, Jun 27, 2018, 12:05 AM UTC

nemothekid wrote: post #25

Facebook has been using RocksDB more and more (now messenger, but also Instragram’s flavor of Cassandra). I wonder if Google has a similar penetration of LevelDB (and we just don’t hear about it because Google’s infrastructure work isn’t open source)

No, it does not. Generally speaking, Google "converges" a layer up (BigTable, Spanner, Colossus). There is no layer like LevelDB that is common to all of these.

Re: Migrating Messenger storage to optimize performance

#27

Post by tomnipotent » Wed, Jun 27, 2018, 12:14 AM UTC

wenc wrote: post #23

tomnipotent wrote: post #2

TL;DR - Moved from HBase to MyRocks engine on MySQL sitting on top of NVMe storage via their Lightning Server [1], which is a JBOF (just a bunch of flash) setup using x16 PCIe. [1] https://code.facebook.com/posts/989638804458007/introducing-...

Anyone know why Facebook moved off HBase? (article doesn't address this) I get that MyRocks is truly amazing, but I'm wondering what issues they were facing with HBase. I heard HBase was picked over Cassandra (developed at FB) because it was strongly consistent vs Cassandra's eventual consistency.

My guess is operational experience, though the article mentions it was necessary to take advantage of Lightning. I can't think of another business on the planet that has pushed MySQL (and RDBMS' in general) further than FB.

Re: Migrating Messenger storage to optimize performance

#28

Post by dingo_bat » Wed, Jun 27, 2018, 1:58 AM UTC

Whatever you may think of social networking, Facebook takes huge amount of pains to ensure reliability. They moved all the data from spinning disks to flash, also migrating to a new db. No downtime at all.

I'm a bit unclear as to how this process resulted in 90% decreased storage use.

Re: Migrating Messenger storage to optimize performance

#29

Post by martincmartin » Wed, Jun 27, 2018, 2:29 AM UTC

dingo_bat wrote: post #28

Whatever you may think of social networking, Facebook takes huge amount of pains to ensure reliability. They moved all the data from spinning disks to flash, also migrating to a new db. No downtime at all. I'm a bit unclear as to how this process resulted in 90% decreased storage use.

"The simplified data schema directly reduced the size of data on disk. We saved additional space in MyRocks by applying Zstandard, a state-of-the-art lossless data compression algorithm developed by Facebook. We were able to reduce the replication factor from six to three, thanks to differences between the HBase and MyRocks architectures. In total, we reduced storage consumption by 90 percent without data loss, thereby making it practical to use flash storage."

Re: Migrating Messenger storage to optimize performance

#30

Post by kalleboo » Wed, Jun 27, 2018, 3:19 AM UTC

spyspy wrote: post #15

oerpli wrote: post #4

They say that they brought some new search features to mobile, though I would prefer if they fixed their search on desktop (or in general) first, as it only returns results from recent messages. Until sometime in 2016/2017 it was possible to look for specific things at whatever time (e.g. 2011) and now even things from <3y ago don't return anything.

I don't see the ability to search within the app. Have they not rolled it out yet?

On iOS I see a search bar at the top of the home screen. Type in it and it searches contacts, but there's a "search in messages" item you can tap and it shows matching chats and messages.