[[TracNav(TOC)]]

= How-To and FAQ =

You may want to consult these sources of information in addition:
   * [wiki:Install How to install]
   * [wiki:FormatsSupported Data formats supported]

== Questions and Answers ==

=== Installation ===

 * '''Q: Using ''automake'' I get an error message "directory should not contain /" - what can I do?'''

   A: Probably you have an outdated automake version installed, we have seen such problems with 1.7.9. Upgrade to at least 1.10.1.

 * '''Q: While installing rasdaman I find out, during ''./configure'', that some further packages are required. Can you give a summary of these?'''

   A: These are summarized on the [wiki:Download Download] page.

 * '''Q: Having done all the above, ''./configure'' complains about missing ''curses'' although ''ncurses'' is there.'''

   A: You have run into a [http://bugs.gentoo.org/67481 bug in the ncurses package]; in /usr/lib, manually create symlinks ''libcurses.a -> libncurses.a'' and ''libcurses.so -> libncurses.so''.

 * '''Q: configure complains that some required files, like install-sh, cannot be found.''' 

    A: retry {{{./configure}}} after running
{{{
automake --add-missing
}}}

 * '''Q: I get C++ compilation errors.'''

   A: Make sure you use the proper compiler version (see [wiki:Requirements]). GNU folks have a relaxed view on backwards compatibility even with minor release changes, and we have experienced problems related to this in the past.

=== PostgreSQL ===

 * '''Q: I get a link error, function ECPGget_connection cannot be found.'''

   A: What appears to have happened is that in PostgreSQL 8.3.0 they removed ECPGget_connection and they have reintroduced it by 8.3.7. So PostgreSQL versions 8.3.0 up to (but excluding) 8.3.7 cannot be used.

 * '''Q: I want to use a different version of PostgreSQL. Is that possible?'''

   A: You need to include a different JDBC postgresql driver (as a JAR) in the libraries folder and update the Makefile as needed. Then you can try out another PostgreSQL version, it may or may not work. Let us know your experiences to update this information!

 * '''Q: When running the script "create_db.sh", I get the following cryptic error message: ''Creating base RASBASE...Warning/error in AdminIf Connect: SQLSTATE: 08001 SQLCODE: -402'' '''

   A: There are several possible reasons:
      '''Execution permissions.''' Run the script as the user owning the postgresql processes. Use '''only''' that user for further work with rasdaman (see Installation Guide). If you use Ubuntu and installed postgres with apt-get, then logging in as user '''postgres''' is an option; I personally like to have a separate user ''rasdaman'' for this purpose where I also can set paths etc. to the executables once and for all. (The postgres db does not allow full access to rasdaman tools, because they do not run under the administrative user that launched the db server process.)

      '''Blocked incoming connections.''' Another cause of the problem might be that postgres does not allow incoming connections. If you have Postgres v8 or more recent, modify file "postgresl.conf" and set (uncomment) the option 
{{{
listen_addresses = 'localhost'
}}}

      '''TCP-IP connection.''' If you have Postgres v7, set (uncomment) the following option:
{{{
tcpip_socket = true
}}}

=== Rasql queries ===

 * '''Q: This query doesn't work:'''
{{{
for c in (rgb) return encode(log(c.0), "jpeg")
}}}

   A: The '''log''' function needs positive numbers as arguments, and will return -Infinity if the argument is 0. You need to make sure that the input does not contain any zeros. You can check that using the query
{{{
for c in (rgb) return count(c.0 = 0)
}}}

   '''''Solution''''' : Add 1 to the input:
{{{
for c in (rgb) return encode(log(c.0+1), "jpeg")
}}}

 * '''Q: When using division "/" as an induced operation I get integer results instead of floats.'''

   A: Division of two integers yields an integer. If you want to have a float result then you need to cast the operands (that is: at least one of them) to float or double.

 * '''Q: This insert query produces error 821 (cell type mismatch) although I provide a TIFF file with correct pixel type:'''
{{{
insert into FloatCollection values inv_tiff( $1 )
}}}

   A: You need to provide an explicit cast (see section 9.8 in the Rasql Guide); a correct phrasing of this query is:
{{{
insert into FloatCollection values (float) inv_tiff( $1 )
}}}

=== Rasj and Java ===

 * '''Q: Aggregation result from ''select max_cells(c.0) from rgb as c'': If I send this query via command line (rasql utility), then the result is 255 as expected; if I send this query via RasJ, then the result is -1.'''

   A: Java does not have an 8-bit unsigned data type. Byte is a signed 8 bit and hence 255 is represented as -1. What you can do is to transform bytes to char by adding 2^8 if the 2^7 bit is set. Tested, works.

 * '''Q: Using ''automake'' on petascope I get an error message "directory should not contain /" - what can I do?'''

   A: Probably you have an outdated automake version installed, we have seen such problems with 1.7.9. Upgrade to at least 1.10.1.

 * '''Q: I get weird error messages from the Java runtime system which seems to hint at class version incompatibilities, such as "Class version error" or "Class not found".'''

   A: There might be a conflict with the locally provided libraries, to be found at directory $PETASCOPE/lib. Check them, and if you find a mismatch then remove them and use the resp. libraries of your local installation instead. Alternatively, consider upgrading your Java SDK to version 1.6.


=== WCPS ===