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MDBM – High-speed database

159 pointsby threepointoneover 10 years ago

18 comments

otterleyover 10 years ago
I&#x27;m so excited that they finally open-sourced this. It&#x27;s relatively old tech at Yahoo, stuff folks outside never got to see. It was difficult to explain to later colleagues the stuff I knew about shared-memory databases because I couldn&#x27;t give them a frame of reference.<p>mdbm performance is even better on FreeBSD than Linux because FreeBSD supports MAP_NOSYNC, which causes the kernel not to flush dirty pages to disk until the region is unmapped. Perhaps mdbm&#x27;s release will finally get the Linux kernel team to provide support for that flag.
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justin66over 10 years ago
This looks interesting. At this stage of the game a more meaningful benchmark might involve LMDB, Wiredtiger, and, yes, LevelDB.
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remonover 10 years ago
I&#x27;m not very comfortable with storage engines that directly build on memory mapped files. MongoDB&#x27;s current storage engine is mmap based and it&#x27;s sub optimal at best which is undoubtedly part of the reason they&#x27;re building a completely new storage engine now (WiredTiger).
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PhuFighterover 10 years ago
I&#x27;m curious to see what the total timings would be like to get the data in a useable form - as opposed to just fetching a record from a data store. As noted - these data stores just store and retrieve data and don&#x27;t do things like joins or ordering, etc.<p>Could there be a comparison between these datastores and the traditional ACID compliant databases when it comes to retrieving actual data in a useful format? E.g. perhaps doing a join or an ordering of some sort? I don&#x27;t expect databases (e.g. Oracle, MS SQL Server, DB2) to be faster in raw performance, but I do expect them to be faster in terms of total development time and bug fixing since the application developer wouldn&#x27;t have to do the locking, page pinning&#x2F;unpinning, etc. manually.
chatmanover 10 years ago
Let the horrors of MDBM not get to you. I&#x27;ve used it when I worked at Yahoo, and the client support for Java etc. sucks.
swahover 10 years ago
Could not install this in Ubuntu 12.04 - basic commands are failing. I think they tested only in BSD?<p>ln -s -f -r &#x2F;tmp&#x2F;install&#x2F;lib64&#x2F;libmdbm.so.4 &#x2F;tmp&#x2F;install&#x2F;lib64&#x2F;libmdbm.so ln: invalid option -- &#x27;r&#x27; Try `ln --help&#x27; for more informatio
coreymgilmoreover 10 years ago
Thoughts on using this as a cache instead of memcache or redis? Yes, it does not have nearly as many features or functions but when raw performance is needed I could see this working (given an api for using this via Node.JS, PHP, etc.).
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qwertaover 10 years ago
I dont want to brag. But there is also DBM inspired Java port. And in-memory mode outperforms java heap collections such as j.u.HashMap.
polskibusover 10 years ago
Can anyone say whether it would be hard to port it to Windows? Maybe there already is something for Windows that is as good as this ?
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discardoramaover 10 years ago
How is MDBM for concurrent access? How does it handle locking (i.e., one big lock that blocks everyone else, or key-level locking)?
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mbrzustoover 10 years ago
How similar in performance is MDBM to GDBM (the GNU DBM)? They appear to be similar (if not identical) in functionality.
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i_am_ralphtover 10 years ago
Where is the original open source release from Silicon Graphics which Yahoo based this work on? Did they ever make one?
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jwrover 10 years ago
This is a very big deal, especially because of the BSD licensing.
swahover 10 years ago
Where does it say that this database is persistent?
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EGregover 10 years ago
How is this different than memcache?
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philliphaydonover 10 years ago
Do people get annoyed by all the JavaScript frameworks and Databases coming out in regards to adoption from a company point of view? I mean every other day a new database comes out and claims to be better in one way or another than something else and then its like &quot;fuck I picked X when now there&#x27;s Y&quot;<p>It seems over the last year technology has been growing more rapidly than any other period.<p>Fun times but so hard to keep track of everything!
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extralamover 10 years ago
yahoo back to IT company ?
extralamover 10 years ago
interesting. follow