[mapguide-users] SDF File Size(Maximum)

[Kenneth, GEOGRAF A/S]

Hmm... a bit hasty there... the new info shows this:

(10) Are there any known size limits to SQLite databases?

    A database is limited in size to 2 tibibytes (2^41 bytes). That is a 
theoretical limitation. In practice, you should try to keep your SQLite 
databases below 100 gigabytes to avoid performance problems. If you need 
to store 100 gigabytes or more in a database, consider using an 
enterprise database engine which is designed for that purpose.

    The theoretical limit on the number of rows in a table is 2^64-1, 
though obviously you will run into the file size limitation prior to 
reaching the row limit. A single row can hold up to 230 bytes of data in 
the current implementation. The underlying file format supports row 
sizes up to about 2^62 bytes.

    There are probably limits on the number of tables or indices or the 
number of columns in a table or index, but nobody is sure what those 
limits are. In practice, SQLite must read and parse the original SQL of 
all table and index declarations everytime a new database file is 
opened, so for the best performance of sqlite3_open() it is best to keep 
down the number of declared tables. Likewise, though there is no limit 
on the number of columns in a table, more than a few hundred seems 
extreme. Only the first 31 columns of a table are candidates for certain 
optimizations. You can put as many columns in an index as you like but 
indexes with more than 30 columns will not be used to optimize queries.

    The names of tables, indices, view, triggers, and columns can be as 
long as desired. However, the names of SQL functions (as created by the 
sqlite3_create_function() API) may not exceed 255 characters in length.

So, it should in fact support 2 titibytes, providing that the file 
system allows you to create files of that size (and you have enough 
storage space).

Regards, Kenneth, GEOGRAF A/S



Kenneth, GEOGRAF A/S skrev:
> SDF is using the SQLite database for storage. The SQLite has the 
> following size constraints:
>
> (10) Are there any known size limits to SQLite databases?
>
>     Internally, SQLite can handle databases up to 2^40 bytes (1 
> terabyte) in size. But the backend interface to POSIX and Win32 limits 
> files to 2^31 (2 gigabytes).
>
>     SQLite arbitrarily limits the amount of data in one row to 1 
> megabyte. There is a single #define in the source code that can be 
> changed to raise this limit as high as 16 megabytes if desired.
>
>     There is a theoretical limit of about 2^32 (4 billion) rows in a 
> single table, but there is no way to test this limit without exceeding 
> the maximum file size, so it is not really an issue. There is also a 
> theoretical limit of about 2^32 tables and indices, but again it is 
> not really possible to reach this limit due to the file size constraint.
>
>     The name and "CREATE TABLE" statement for a table must fit 
> entirely within a 1-megabyte row of the SQLITE_MASTER table. Other 
> than this, there are no constraints on the length of the name of a 
> table, or on the number of columns, etc. Indices are similarly 
> unconstrained.
>
> So, if there are no bugs in the implementation, the size should be 
> limited to 2 GB. You can read more about the SQLite format on:
> http://www.sqlite.org/
> Regards, Kenneth, GEOGRAF A/S
>   
>
> Rahul skrev:
>> Hi All,
>>           Can anyone tell me that how much the maximum SDF File 
>> size(single) supported by Autodesk(ADSKServer,Map3D 2008).Any 
>> reference or detail link will be really helpfull for me.
>>  
>> ESRI use to provide support for max. 4 GB personal geodatabase File.
>>  
>> Thks
>> Max
>>
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