Re: [MonetDB-users] Embedded Use: Persisting and Metadata

>From a C/C++ code, how do I access the MAL level storage operators? I would
assume that using the right libraries I should be able to get this data into
my C/C++ code. Could you please point me to the right resources here?
Thanks.

Further, I want to know the storage cost on disk for the entire database. As
I see the data is stored as a "farm". Does this mean that I can sum the
sizes of all files under the root folder to get the disk storage cost?

~Yuva


On Feb 9, 2008 12:10 AM, Martin Kersten  wrote:

> Yuvaraj Athur Raghuvir wrote:
> > Thanks.
> >
> > Regarding db size, I would expect that the storage strategy will have
> > additional overheads due to bookkeeping requirements necessary for
> > reconstruction of the relations between the data elements. Since there
> > are no indices (I assume this due to columnar storage) I can discount
> > on the space required for indices.
> >
> Indices are automatically created and dropped as a side effect of queries.
> They disappear at the end of a session.
>
> > Are there Mapi calls that I can use to determine the size of the
> > tables? I would like to horizontally partition the data across
> > multiple stores based on table size and growth estimates.
> >
> the SQL level does not open up the kernel information about storage
> requirements.
> At the MAL level several operators are available to assess storage cost.
> > ~Yuva
> >
> >
> > On 08/02/2008, Yuvaraj Athur Raghuvir  wrote:
> >
> >> Finally, I have managed to get the Mbeddded example working in VC++
> 2005
> >> Express Edition on Windows XP ! Thanks to the folks in the mailing
> list.
> >>
> >> Use Case: MonetDB5 , Embedded Mode , SQL
> >>
> >> To move towards the application I intend to experiment on, I need some
> more
> >> information:
> >> 1) How to make data durable?  In the simple example,  I tried the
> following:
> >> a)  First Run: Create table and insert rows. Select to check if
> everything
> >> is ok.
> >> b) Second Run: Only perform selection
> >>
> >>>> I get an error in the second run.
> >>>>
> >> 2) How to get meta data of the database?
> >> a) I want to know the size of the tables and meta tables in the data
> base.
> >> In particular I am interested in seeing the growth of the database on
> >> addition of content.
> >> b) Typically, there is a master table in the database that records
> >> information of the schema persisted. What is the name of the Master
> Table
> >> and its schema in MonetDB?
> >> c) SQLite has an independent analyzer tool which dumps the state of the
> >> storage from which I can extract most of the data I need. Does MonetDB
> have
> >> a similar mechanism?
> >>
> >> ~Yuva
> >>
> >>
> >>>>>> code snippet >>>>>
> >>>>>>
> >>     dbh = embedded_sql (set, setlen);
> >>     if (dbh == NULL || mapi_error(dbh))
> >>         die(dbh, hdl);
> >>     /* switch off autocommit */
> >>     if (mapi_setAutocommit(dbh, 0) != MOK || mapi_error(dbh))
> >>         die(dbh,NULL);
> >>     if ((hdl = mapi_query(dbh, "create table emp"
> >>     " (name varchar(20),age int)")) == NULL || mapi_error(dbh))
> >>         die(dbh, hdl);
> >>     close_handle(dbh,hdl);
> >>     for(i=0; i< 1000; i++) {
> >>         char query[100];
> >>         _snprintf(query, 100,"insert into emp values(\'user%d\', %d)",
> i, (i
> >> % 82));
> >>         if ((hdl = mapi_query(dbh, query)) == NULL || mapi_error(dbh))
> >>             die(dbh, hdl);
> >>         close_handle(dbh,hdl);
> >>     }
> >>     if ((hdl = mapi_query(dbh, "select * from emp")) == NULL ||
> >> mapi_error(dbh))
> >>         die(dbh, hdl);
> >>     i=0;
> >>     while (mapi_fetch_row(hdl)) {
> >>         char *age = mapi_fetch_field(hdl, 1);
> >>         i= i+ atoi(age);
> >>     }
> >>     if (mapi_error(dbh))
> >>         die(dbh, hdl);
> >>     close_handle(dbh,hdl);
> >>     printf("The sum is %d \n",i);
> >>     mapi_disconnect(dbh);
> >>     return 0;
> >>
> >>
> >
> >
> -------------------------------------------------------------------------
> > This SF.net email is sponsored by: Microsoft
> > Defy all challenges. Microsoft(R) Visual Studio 2008.
> > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> > _______________________________________________
> > MonetDB-users mailing list
> > MonetDB-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/monetdb-users
> >
>
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2008.
> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
> _______________________________________________
> MonetDB-users mailing list
> MonetDB-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/monetdb-users
>