can we set max cache size? like 1mb of cache?
Roberto Spadim escreveu:
>today implementation don't have problems!
>
>maybe an new directory could help, see:
>
>when we get from "/#OW SYSTEM#/#ANY FILE OR DIRECTORY#" (could be
>"/ow_device_manager/#ANY FILE OR DIRECTORY#")
>OW SYSTEM:
> ow system that's connected direct to ds2480 or ds2490 or another
>dsxxxx
>
>this directory could work like this:
>
>init(" owserver ");
>get(" settings values ");
>put("/settings/timeout/network",0);
>put("/settings/timeout/stable",0);
>put("/settings/timeout/volatile",0);
>put("/settings/timeout/ another timeout configurations ",0);
>$value=get(" getting now will be expired cache value, we will get from
>owserver :) ");
>put(" set settings back again ",setting_value);
>echo "$value";
>
>i can do it with php, but time to change and set again configuration is
>very big for a single read.
>
>*****************
>cache system ideas:
>
>SQLITE
>sqlite good things:
>we can SEE the cache
>
>good thinks about sqlite library (www.sqlite.org):
>Small code footprint: less than 250KiB fully configured or less than 150KiB
>with optional features omitted.
>Supports databases up to 2 terabytes (241 bytes) in size. (no problem with
>264 device)
>A complete database is stored in a single disk file.
>Implements most of SQL92.
>Zero-configuration - no setup or administration needed.
>Self-contained: *no external* dependencies.
>
>
>*have windows and posix support!!!!*
>
>SQLITE PROBLEMS:
> maybe anyone could delete file or change table values or put incorrect
>values on cache system, write lock on file must be done
> if sqlite is used with ":memory:" (in memory database) just owserver
>will see the database, may be it could be used only with filesystem cache
>
>if sqlite is faster than today implementation AND with small footprint, we
>could change today implementation for non uclinux compilations too, we need
>to see if memory usage is bigger or small with sqlite library too
>
>we don't need to delete expirate values, a field could say the last time
>that cache was updated and an SQL statment could filter the value like:
>"SELECT value FROM cache_table WHERE file='balbalbal' AND expiration_time>=
>current_time ", maybe when owserver end or start database could be
>cleaned...
>
>
>ANOTHERS
>
>anothers cache systems could be: the system used in MMTurck or eaccelerator
>or APC or memcache (php libraries from pecl.php.net) or Berkeley DB or
>(http://www.danga.com/memcached/) :
>Memcached is a caching daemon designed especially for dynamic web
>applications to decrease database load by storing objects in memory.
>MEMCACHE PROBLEMS:
> server must run before ow,
> could be used for non uclinux too,
> maybe sqlite could be faster, if disk write and read is faster than IP
>communication.
> If memcache server die or don't work what could we do?
> i didn't see documentation of memcache, but i think that we can't see
>all cache contents like an "SELECT * FROM cache_table"
>
>COMMENTS:
>
>i don't know if database systems could help, we need fast systems and i
>don't like another program running like mysqld or oracle daemon or
>postgrees daemon or firebird daemon or XXX daemon, maybe embbeded solutions
>like sqlite or filebased databases could help. without server running cache
>is locked, using filebased database we just need file access to write and
>read, today i just run owserver with root... i don't have privileges
>problems for files, for windows the same thing just run like administrator
>if we will use filebased, we need to remember that files can be shared...
>if we put it on network filesystems maybe many owserver can use the
>samefile and table conflicts could occur like duplicated settings values,
>we need to put mac address to know what server we are, or another unique
>ID...
>just building to test and know if it really work...
>
>
>Paul Alfille escreveu:
>
>>Hi Robero. You certainly are exploring the entire program!
>>
>>Currently the cache is an in-memory binary tree. There is some information
>>at http://www.owfs.org/index.php?page=cache
>><http://www.owfs.org/index.php?page=cache>
>>
>>Several different things are cached:
>>1. devices (basically if a serial number was found, and on which bus)
>>2. directory lists (lists of serial numbers for a given path)
>>3. "file" contents ( things like serialnumber/temperature )
>>4. Hidden properties (like cumulative counters, and barometer calibration
>>factors)
>>
>>Cached items also store their termination time.
>>
>>We actually use two binary trees, one for new entries, and one that is
>>older. The older one doesn't get updated, and eventually expires entirely,
>>and gets deleted. At that point, the newer one becomes the older one, and
>>a new one is started.
>>
>>This means that we never have to scan through all the items with see which
>>are too old, and stale entries are guarnteed to be deleted in a reasonable
>>time period.
>>
>>So, could the cache be stored in SQLite? Sure. Could it be backed up by a
>>physical file? Sure. What would the advantage be? Binary trees are quite
>>fast for adding and retrieving. Glibc and uClibc both have support built
>>in for binary trees so external libraries are needed.
>>
>>There are some problems with the current scheme. If you have owfs
>>connecting to owserver, each has it's own cache. It is possible for the
>>caches to be out of synch, especially if several programs are connected to
>>owserver. Reading "uncached" values will always work, and cache problems
>>time themselves out quickly in any case.
>>
>>An alternative design would be a separate owcache program. Cache would be
>>consistent, and not repeated, but communication efficiency might swamp
>>space efficiency. I didn't do it because of the complexity.
>>
>>Tell me what you see as the deficiencies of the current scheme.
>>
>>Paul Alfille
>>
>>On 10/14/06, *Roberto Spadim* <[EMAIL PROTECTED]
>><mailto:[EMAIL PROTECTED]>> wrote:
>>
>> Hello guys, i was thinking about cache system...
>> can we use cache in filesystem?
>> like in sqlite we can use
>> sqlite_open(":memory:");
>> to use database on memory and
>> sqlite_open("/file.sqlite");
>> to open an file
>> could we set the "file_name" of cache system?
>> if we put "NULL" the cache system could be turned off
>> what you say?
>>
>> have anyother database system that is fast than today database?
>> sqlite
>> could be used? we are using berkley?
>> could we select "file_name" for
>> Old Cache data
>> New Cache data
>> Persistent data
>>
>> in diferent "files"??
>> thankx guys :)
>>
>> "files" could be memory or real file
>>
>>
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