What is your preferred VCS?
in [ADA]
|
From: Tero Koskinen on 2 Aug 2010 14:01 Hi, Another Monotone user and (occasional) developer here. On 08/02/2010 07:21 PM, Marcelo Cora�a de Freitas wrote: > On 1 ago, 07:13, Ludovic Brenta<ludo...(a)ludovic-brenta.org> wrote: >> This looks like the memory leak that was fixed in monotone version 0.27, >> back in 2006. And the latest version, 0.48, has additional performance >> improvements for very large trees. > > I am not quite sure we are talking about the same bug. This has been > detected in 2009/2010 and the Edward O'Callaghan from AuroraUX was in > touch with one of the monotone developers. I don't know exactly what > happened as I had to focus on other things. I am not sure is the poor clone/pull performance an actual bug. It could be related to the way Monotone is designed. First, different sections/layers of Monotone have abstracted interfaces. For example, you can swap network protocol or internal change set/database implementation with another and leave other parts untouched. This might affect performance, although in theory the impact should be small. Second, by default, Monotone uses backward deltas for change sets. This means that only the files in the latest revision are stored in their full form. Other revisions are recorded just as difference from their child revision. To build 10th newest revision (head-9) you need to apply deltas from head-1 to head-9 on top of head. And to build the first revision, you need to apply all deltas. The recent versions of Monotone also support forward deltas, but they need to be turned on explicitly, because then the disk space usage increases. Third, before sending or receiving anything, Monotone calculates sha1 checksums for the data. I am not totally sure, but I think that when you request full clone of a repository, Monotone constructs each revision (using those backward deltas) from first to latest and calculates checksums for them. This ensures data integrity but also takes somewhat long time. There have been experiments where the checksum calculation/checking has been removed and it has shown performance boost, but developers prefer to have those checks on. That checking has revealed data corruption and disk failures on real systems before operating system's own mechanisms have detected anything. Some references: 6 minute pull CPU time for AuroraUX with no checking: http://colabti.org/irclogger/irclogger_log/monotone?date=2010-02-12#l7 (No idea what was the actual wall clock time.) 20% increase in pull time for AuroraUX: http://colabti.org/irclogger/irclogger_log/monotone?date=2010-02-09#l147 (This improvement is in 0.47 or 0.48) -Tero
From: Randy Brukardt on 3 Aug 2010 00:21 "Karel Miklav" <karel(a)lovetemple.net> wrote in message news:i2ve9u$1qg2$1(a)adenine.netfront.net... > deadlyhead wrote: >> For those who like Monotone: is using a "real database" really that >> much of advantage? > > Where the hell this meme still draws the power from? I have not seen a > real application with a bunch of files at its core for a long time and I > do not really believe you are not aware of advantages of database over the > filesystem. Well, let's see. Pretty much every Ada compiler uses the file system rather than some sort of database at its core. Would you claim that GNAT is not a "real application"?? Personally, I think there is way too much use of "real databases" for programs that will find no real advantage to them. When you use an SQL database as part of your program, you are introducing communcations issues, a second programming language (with all of the problems that mixed language programming entails), an additional large piece of software that needs separate maintenance and patching (many attacks occur through databases), and huge waste of resources. The latter isn't as important as it once was (I still think any program over 4 megabytes is amazingly bloated; given that most computers have more than 1GB of memory, that probably isn't quite true), but the other factors still are true. There clearly are applications that benefit from a database (as when there is actually data that needs to be searched/indexed), but for most applications (especially the smaller ones), the costs of a database outweigh the benefits. Randy.
From: nobody on 13 Aug 2010 16:23
I like CM/Synergy. It was actually the first one I came in contact with and it has everything I need and then some. One special thing that I miss in all the others I have tried is task-based cm. The main thing that give me is the ability to check out files into a task and when the fix or new function is finished you just say complete task and all the files affected are checked in for you. You can naturally have many tasks active in parallell and updating your working project is based on what tasks have been completed. |