This is very cool! Is this pushed anywhere and/or proposed for merge yet?
On 07/11/2010 09:49 AM, ZQ wrote: > http://www.dazuiniu.com/blog/2010/07/11/the-status-of-filesystem-storage-engine-in-drizzle.html > > The file system storage engine is in shape now. > > There are lots of storage engines in Drizzle already. What’s this new > storage engine used for? To give you a rough idea, you can use the > below SQL statement to read the file ‘/proc/loadavg’ directly. > > drizzle> CREATE TABLE LoadAverage ( > load1 DECIMAL(3, 2), > load5 DECIMAL(3, 2), > load15 DECIMAL(3, 2), > active_processes VARCHAR(12), > lastpid INTEGER) ENGINE=FILESYSTEM, FILE="/proc/loadavg"; > > > drizzle> select * from LoadAverage; > +-------+-------+--------+------------------+---------+ > | load1 | load5 | load15 | active_processes | lastpid | > +-------+-------+--------+------------------+---------+ > > | 0.00 | 0.00 | 0.00 | 1/97 | 6061 | > +-------+-------+--------+------------------+---------+ > > The file system storage engine eases our manipulation on disk file, > especially those file under /proc directory. This engine tries to be > small and useful, like the calculator at your hand. > > There are several options available for this storage engine for now. > Extra options provides extra functionalities. > > 1. *FILE*. This option specifies which file composes the > corresponding table. This is the most important and useful > option, it’s a MUST option for this storage engine. > 2. *ROW_SEPARATOR*. This option specifies which characters should be > taken as end-of-line. The default is “\n”. > 3. *COL_SEPARATOR*. This option specifies which characters should be > taken as the delimiter for columns. The default is ” \t” (space > and tab), it’s reasonable to make it as default. > 4. *SEPARATOR_MODE*. It has three values, STRICT, GENERAL, WEAK. > This one is a little tricky to understand. It shows the rule how > to treat continuous separators. For example, if we have the line > “111<SPACE><SPACE><SPACE>222″, the columns in WEAK mode would be > only two columns “111″ and “222″; the columns in other modes would > be four columns “111″, NULL, NULL, “222″. GENERAL mode will omit > empty lines in the file; while STRICT mode will ruthlessly add an > entire empty tuple into this table. > 5. *FORMAT*. This is a newly added feature. It’s written to process > the file “/proc/meminfo”. This file has the similar format as key > and value each line. What about we transpose these columns and > rows and make all these keys as the column in a table? That should > be cool. Yes, we can do this. Specify “KEY_VALUE” as the value of > this option and set the FILE to ‘/proc/meminfo’, here you go: > > CREATE TABLE t1 (a int) > ENGINE=FILESYSTEM,FILE="/proc/meminfo",FORMAT="KEY_VALUE",COL_SEPARATOR=": "; > SELECT * FROM t1; > Active AnonPages Bounce Buffers Cached CommitLimit > Committed_AS DirectMap2M DirectMap4k Dirty HugePages_Free > HugePages_Rsvd HugePages_Surp HugePages_Total Hugepagesize > InactiveMapped MemFree MemTotal NFS_Unstable PageTables > SReclaimable SUnreclaim Slab SwapCached SwapFree > SwapTotal VmallocChunk VmallocTotal VmallocUsed Writeback > WritebackTmp > > 1526364 198768 0 221004 2829356 2600136 495728 4186112 7040 > 1916 0 0 0 02048 1722772 51064 502844 4059680 0 > 27124 198000 12076 210076 0 570296 570296 34359655499 > 34359738367 82808 0 0 > > SHOW CREATE TABLE t1; > Table Create Table > t1 CREATE TABLE `t1` ( > `Active` varchar(8) DEFAULT NULL, > `AnonPages` varchar(7) DEFAULT NULL, > ...some lines omitted... > `Writeback` varchar(2) DEFAULT NULL, > > `WritebackTmp` varchar(2) DEFAULT NULL > ) ENGINE=FILESYSTEM FILE='/proc/meminfo' FORMAT='KEY_VALUE' > COL_SEPARATOR=': ' > > There are still some TODOs on my list: > > 1. enclosing and quotation is not there. > 2. more test cases to cover some corner cases. > 3. … > > I would like my project to be useful, and I encourage all DBAs, > administrators to give a try and see whether it fits your daily use. > Any feedback is welcome! :-) > > > > --Zimin > > > > _______________________________________________ > Mailing list: https://launchpad.net/~drizzle-discuss > Post to : [email protected] > Unsubscribe : https://launchpad.net/~drizzle-discuss > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~drizzle-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~drizzle-discuss More help : https://help.launchpad.net/ListHelp
