where is my match, do i wonder wrong.. or am i shy,..

Is it passing slow, or my wait’s too tough..

am i lost somewhere, or am i feeling so high..

is this seriousness an issue, or my jokes have fade out..

i’m talking too fast, can u hear me, argh! why..

the time’s not right, or this place, might be..

i’ve a mission, an aim, and my only try..

i’m holding it tight, No worries, My match..!!!

I’ll be there someday, & you know why..

Synopsis Abstract:
Data warehousing being a dominant dimension in information storage, retrieval and understanding; comes up with a challenge of managing data of versatile structure. Relational data sources and XML structured data are found popular for storage. The chapter considers describing in detail the method of designing data mart to a given DTD from the above mentioned storage structures; relational data sources and XML documents. The method is also supported by the explanation of a use case example from the real world.

Synopsis:
In the competitive market of the present, where think tanks enrich companies with their creative and innovative prospective of judging scenarios, data warehousing plays an equal role for providing fact based statements by analyzing data been stored in huge amount. Decision support system (DSS) assist data warehouse (DW) in analyzing this large volumes of data. The companies mostly provide the data to DW in form one relational data source [1], but for an optimum DW it is mandatory to provide the flexibility of changing the source type to any other type like XML one of the most common data structure for web resources mainly.
In previous related work, [2] proposed the way of creating a DW on the basis of a XML but with restriction that DTD to the XML was to be provided as well and that XML document would be well formed and valid to the given DTD. In the proposed work the designing method is divided into four steps:
Data Source Pretreatment: In this step the data is resolved from the structural differences of both the input data sources. In case of RDBMS, the structures of tables are extracted from the databases, whereas, for XML DTD works as the structure representative, which are then turned into the relational schemas.

Figure 1: Steps of Data Mart designing
Relation Classification: The obtained source schemas are then examined for the relations in it and conceptual classes are made for every relation which later helps in improving results for fact extraction.
Data Mart Schema Construction: In this step facts with their values and dimensions along with their attributes are retrieved on the basis of extraction rules been defined in order to make star models. These rules are traceable acting upon the syntax mostly and can be used for extraction from various semantically different sources.
Data Mart Adaptation: In this final step the designer of the whole process is given various applicable models been created from the sources. These schemas are adjustable to meet final hour changes for meeting designer’s full satisfaction.
“Conception Assistée de Magasins et d’Entrepôts de données” CAME case toolset provides the implementation of the above mention four steps. An example of e-ticket DTD is also used to elaborate the working of the DM construction from XML document.

Figure 2: CAME case toolset snapshot
Used Abbreviations:
XML: Extensible Markup Language
DTD: Document Type Definition
RDBMS: Relational Databases Management System

References:
[1] Bruckner, R., List, B., & Schiefer, J. (2001). Developing requirements for data warehouse systems with use cases. In Proceedings of the 7th Americas Conf. on Information Systems (pp. 329-335).
[2] Golfarelli, M., Maio, D., & Rizzi, S. (1998). Conceptual design of data warehouses from E/R schemas. In Proceedings of the Conference on System Sciences, Kona, Hawaii. Washington, DC, USA: IEEE Computer Society.

Summary:
Visual Summarization is an innovative new way of representing web pages in a brief yet comprehensive manner. There are mainly two achievements from such summarization. Firstly they act as an overview for webpage retrieval systems and users find it much feasible to look at glimpse of the webpage before visiting it. Secondly, in the task of re-finding visited web pages, visual summarization, are very helpful. Google Chrome, Mozilla FireFox and safari web browsers provide a visual list of most pages order by recent visit or most visits etc.
The Research carried on in the paper proposes a new web pages summarization technique and then compares it other visual summarization techniques.
• Thumbnails
• Visual Snippet
• Internal Images
• External Images (proposed)
Thumbnails are actual resized snapshot of the whole page, where the aspect ratio is kept same. Thumbnails are useful for well formed documents specially having large images and text sizes. Visual snippet provides a dynamic technique to create a composite image runtime which includes the dominant image, title and logo of the webpage. Dominant image are the one that provide proper summarizes the whole web page, and that exists inside the webpage itself. When a summarization is only the dominant image itself it is called Internal Image. But most of the web pages do not have proper Images to represent the webpage. In that scenario, the above techniques fail to provide a proper summarization. The research proposes a new technique External Images, in which internet is searched for representative image. In the technique, first key phrases are extracted from the webpage using KEX algorithm. Various images are retrieved using the key phrases and then the images are filter using cosine string comparison technique of images titles and other details. Ranking of images are created on the basis of visual alikeness with the main page. At the end the representative is selected on the basis of high precedence.
A statistical comparison is drawn between these visual summarization techniques of web pages by taking two kinds of tasks. First, to check the proper summarization of webpage and secondly, to check which one has least error rate in re-finding tasks. Research is concluded by the comparison results, which states that different visual summarization techniques are good for different types of web pages. Thumbnails are good for simple structured web pages, where snippet view is good for the website having many internal images and textual data. Internal and external images are dependent on availability of images in the web pages and proper extraction of key phrases from the page.

References
1. Susan Dziadosz and Raman Chandrasekar. Do thumbnail previews help users make better relevance decisions about web search results? SIGIR ’02 @
2. Zhiwei Li , Shuming Shi , Lei Zhang, Improving relevance judgment of web search results with image excerpts, conference on World Wide Web, Beijing
3. Qing Yu, Shuming Shi, Zhiwei Li, Ji-Rong Wen, and Wei-Ying Ma. Improve ranking by using image information. ECIR’07, Springer-Verlag, Berlin

We can install both slony-I and PostgreSQL from the synapatic manager as well, but in order to get a a smooth working platform for future I prefer building both from source.

The installation was carried out on Intel Core i5 M430 @2.27GHz with 4 GB of RAM with Ubuntu 9.1.

Source Downloads:
Following are the sources available at the time of my installation, you can install the latest versions of them as well:

postgresql-8.4.4.tar.gz was downloaded from here
slony1-2.0.0.tar.bz2 was downloaded from here
Some of the packages you need to install before starting compilation:

• Libreadline5-dev
• Felx
• Bison

You have to use apt-get install to install these packages
Now extract both the archives and let us start with PostgreSQL in the start. In terminal go to the PostgreSQL extracted directory.
Execute the Configure script ./configure, for which I got the following output.

root@mudaser-laptop:/home/mudaser/Downloads/postgresql-8.4.4# ./configure 
checking build system type... i686-pc-linux-gnu
checking host system type... i686-pc-linux-gnu
checking which template to use... linux
checking whether to build with 64-bit integer date/time support... yes
checking whether NLS is wanted... no
checking for default port number... 5432
checking for block size... 8kB
checking for segment size... 1GB
checking for WAL block size... 8kB
checking for WAL segment size... 16MB
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables... 
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking if gcc supports -Wdeclaration-after-statement... yes
checking if gcc supports -Wendif-labels... yes
checking if gcc supports -fno-strict-aliasing... yes
checking if gcc supports -fwrapv... yes
checking whether the C compiler still works... yes
checking how to run the C preprocessor... gcc -E
checking allow thread-safe client libraries... no
checking whether to build with Tcl... no
checking whether to build Perl modules... no
checking whether to build Python modules... no
checking whether to build with GSSAPI support... no
checking whether to build with Kerberos 5 support... no
checking whether to build with PAM support... no
checking whether to build with LDAP support... no
checking whether to build with Bonjour support... no
checking whether to build with OpenSSL support... no
checking for grep that handles long lines and -e... /bin/grep
checking for egrep... /bin/grep -E
checking for ld used by GCC... /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking for ranlib... ranlib
checking for strip... strip
checking whether it is possible to strip libraries... yes
checking for ar... ar
checking for tar... /bin/tar
checking whether ln -s works... yes
checking for gawk... no
checking for mawk... mawk
checking for bison... bison
configure: using bison (GNU Bison) 2.4.1
checking for flex... /usr/bin/flex
configure: using flex 2.5.35
checking for perl... /usr/bin/perl
checking for main in -lm... yes
checking for library containing setproctitle... no
checking for library containing dlopen... -ldl
checking for library containing socket... none required
checking for library containing shl_load... no
checking for library containing getopt_long... none required
checking for library containing crypt... -lcrypt
checking for library containing fdatasync... none required
checking for library containing gethostbyname_r... none required
checking for library containing shmget... none required
checking for -lreadline... yes (-lreadline)
checking for inflate in -lz... yes
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking crypt.h usability... yes
checking crypt.h presence... yes
checking for crypt.h... yes
checking dld.h usability... no
checking dld.h presence... no
checking for dld.h... no
checking fp_class.h usability... no
checking fp_class.h presence... no
checking for fp_class.h... no
checking getopt.h usability... yes
checking getopt.h presence... yes
checking for getopt.h... yes
checking ieeefp.h usability... no
checking ieeefp.h presence... no
checking for ieeefp.h... no
checking langinfo.h usability... yes
checking langinfo.h presence... yes
checking for langinfo.h... yes
checking poll.h usability... yes
checking poll.h presence... yes
checking for poll.h... yes
checking pwd.h usability... yes
checking pwd.h presence... yes
checking for pwd.h... yes
checking sys/ipc.h usability... yes
checking sys/ipc.h presence... yes
checking for sys/ipc.h... yes
checking sys/poll.h usability... yes
checking sys/poll.h presence... yes
checking for sys/poll.h... yes
checking sys/pstat.h usability... no
checking sys/pstat.h presence... no
checking for sys/pstat.h... no
checking sys/resource.h usability... yes
checking sys/resource.h presence... yes
checking for sys/resource.h... yes
checking sys/select.h usability... yes
checking sys/select.h presence... yes
checking for sys/select.h... yes
checking sys/sem.h usability... yes
checking sys/sem.h presence... yes
checking for sys/sem.h... yes
checking sys/socket.h usability... yes
checking sys/socket.h presence... yes
checking for sys/socket.h... yes
checking sys/shm.h usability... yes
checking sys/shm.h presence... yes
checking for sys/shm.h... yes
checking sys/tas.h usability... no
checking sys/tas.h presence... no
checking for sys/tas.h... no
checking sys/time.h usability... yes
checking sys/time.h presence... yes
checking for sys/time.h... yes
checking sys/un.h usability... yes
checking sys/un.h presence... yes
checking for sys/un.h... yes
checking termios.h usability... yes
checking termios.h presence... yes
checking for termios.h... yes
checking ucred.h usability... no
checking ucred.h presence... no
checking for ucred.h... no
checking utime.h usability... yes
checking utime.h presence... yes
checking for utime.h... yes
checking wchar.h usability... yes
checking wchar.h presence... yes
checking for wchar.h... yes
checking wctype.h usability... yes
checking wctype.h presence... yes
checking for wctype.h... yes
checking kernel/OS.h usability... no
checking kernel/OS.h presence... no
checking for kernel/OS.h... no
checking kernel/image.h usability... no
checking kernel/image.h presence... no
checking for kernel/image.h... no
checking SupportDefs.h usability... no
checking SupportDefs.h presence... no
checking for SupportDefs.h... no
checking netinet/in.h usability... yes
checking netinet/in.h presence... yes
checking for netinet/in.h... yes
checking for netinet/tcp.h... yes
checking readline/readline.h usability... yes
checking readline/readline.h presence... yes
checking for readline/readline.h... yes
checking readline/history.h usability... yes
checking readline/history.h presence... yes
checking for readline/history.h... yes
checking zlib.h usability... yes
checking zlib.h presence... yes
checking for zlib.h... yes
checking whether byte ordering is bigendian... no
checking for an ANSI C-conforming const... yes
checking for inline... inline
checking for preprocessor stringizing operator... yes
checking for signed types... yes
checking for working volatile... yes
checking for __func__... yes
checking whether struct tm is in sys/time.h or time.h... time.h
checking for struct tm.tm_zone... yes
checking for tzname... yes
checking for union semun... no
checking for struct sockaddr_un... yes
checking for struct sockaddr_storage... yes
checking for struct sockaddr_storage.ss_family... yes
checking for struct sockaddr_storage.__ss_family... no
checking for struct sockaddr_storage.ss_len... no
checking for struct sockaddr_storage.__ss_len... no
checking for struct sockaddr.sa_len... no
checking for struct addrinfo... yes
checking for struct cmsgcred... no
checking for struct fcred... no
checking for struct sockcred... no
checking for struct option... yes
checking for z_streamp... yes
checking for special C compiler options needed for large files... no
checking for _FILE_OFFSET_BITS value needed for large files... 64
checking for off_t... yes
checking size of off_t... 8
checking for int timezone... yes
checking types of arguments for accept()... int, int, struct sockaddr *, size_t *
checking whether gettimeofday takes only one argument... no
checking for cbrt... yes
checking for dlopen... yes
checking for fcvt... yes
checking for fdatasync... yes
checking for getpeereid... no
checking for getpeerucred... no
checking for getrlimit... yes
checking for memmove... yes
checking for poll... yes
checking for pstat... no
checking for readlink... yes
checking for setproctitle... no
checking for setsid... yes
checking for sigprocmask... yes
checking for symlink... yes
checking for sysconf... yes
checking for towlower... yes
checking for utime... yes
checking for utimes... yes
checking for waitpid... yes
checking for wcstombs... yes
checking for fseeko... yes
checking for _LARGEFILE_SOURCE value needed for large files... no
checking for posix_fadvise... yes
checking whether posix_fadvise is declared... yes
checking whether fdatasync is declared... yes
checking whether strlcat is declared... no
checking whether strlcpy is declared... no
checking whether F_FULLFSYNC is declared... no
checking for struct sockaddr_in6... yes
checking for PS_STRINGS... no
checking for snprintf... yes
checking for vsnprintf... yes
checking whether snprintf is declared... yes
checking whether vsnprintf is declared... yes
checking for isinf... yes
checking for crypt... yes
checking for getopt... yes
checking for getrusage... yes
checking for inet_aton... yes
checking for random... yes
checking for rint... yes
checking for srandom... yes
checking for strdup... yes
checking for strerror... yes
checking for strlcat... no
checking for strlcpy... no
checking for strtol... yes
checking for strtoul... yes
checking for unsetenv... yes
checking for getaddrinfo... yes
checking for getopt_long... yes
checking for rl_completion_append_character... yes
checking for rl_completion_matches... yes
checking for rl_filename_completion_function... yes
checking for replace_history_entry... yes
checking for sigsetjmp... yes
checking whether sys_siglist is declared... yes
checking for syslog... yes
checking syslog.h usability... yes
checking syslog.h presence... yes
checking for syslog.h... yes
checking for opterr... yes
checking for optreset... no
checking for strtoll... yes
checking for strtoull... yes
checking for atexit... yes
checking test program... ok
checking whether long int is 64 bits... no
checking whether long long int is 64 bits... yes
checking snprintf format for long long int... %lld
checking for unsigned long... yes
checking size of unsigned long... 4
checking for void *... yes
checking size of void *... 4
checking for size_t... yes
checking size of size_t... 4
checking whether to build with float4 passed by value... yes
checking whether to build with float8 passed by value... no
checking for short... yes
checking alignment of short... 2
checking for int... yes
checking alignment of int... 4
checking for long... yes
checking alignment of long... 4
checking for long long int... yes
checking alignment of long long int... 4
checking for double... yes
checking alignment of double... 4
checking for int8... no
checking for uint8... no
checking for int64... no
checking for uint64... no
checking for sig_atomic_t... yes
checking for POSIX signal interface... yes
checking for working memcmp... yes
checking for onsgmls... no
checking for nsgmls... no
checking for openjade... no
checking for jade... no
checking for DocBook V4.2... no
checking for DocBook stylesheets... no
checking for collateindex.pl... no
checking for sgmlspl... no
checking for docbook2man... 
checking if gcc supports -Wl,--as-needed... yes
configure: using CFLAGS=-O2 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -fno-strict-aliasing -fwrapv
configure: using CPPFLAGS= -D_GNU_SOURCE 
configure: using LDFLAGS=  -Wl,--as-needed
configure: creating ./config.status
config.status: creating GNUmakefile
config.status: creating src/Makefile.global
config.status: creating src/include/pg_config.h
config.status: src/include/pg_config.h is unchanged
config.status: creating src/interfaces/ecpg/include/ecpg_config.h
config.status: src/interfaces/ecpg/include/ecpg_config.h is unchanged
config.status: linking ./src/backend/port/tas/dummy.s to src/backend/port/tas.s
config.status: linking ./src/backend/port/dynloader/linux.c to src/backend/port/dynloader.c
config.status: linking ./src/backend/port/sysv_sema.c to src/backend/port/pg_sema.c
config.status: linking ./src/backend/port/sysv_shmem.c to src/backend/port/pg_shmem.c
config.status: linking ./src/backend/port/dynloader/linux.h to src/include/dynloader.h
config.status: linking ./src/include/port/linux.h to src/include/pg_config_os.h
config.status: linking ./src/makefiles/Makefile.linux to src/Makefile.port

/bin/sh ../../../config/install-sh -c  pg_regress '/usr/local/pgsql/lib/pgxs/src/test/regress/pg_regress'
make[2]: Leaving directory `/home/mudaser/Downloads/postgresql-8.4.4/src/test/regress'
make[1]: Leaving directory `/home/mudaser/Downloads/postgresql-8.4.4/src'
make -C config install
make[1]: Entering directory `/home/mudaser/Downloads/postgresql-8.4.4/config'
/bin/sh ../config/install-sh -c -m 755 ./install-sh '/usr/local/pgsql/lib/pgxs/config/install-sh'
/bin/sh ../config/install-sh -c -m 755 ./mkinstalldirs '/usr/local/pgsql/lib/pgxs/config/mkinstalldirs'
make[1]: Leaving directory `/home/mudaser/Downloads/postgresql-8.4.4/config'
PostgreSQL installation complete.

mkdir /usr/local /pgsql/bin/data
adduser postgres
chown postgres /usr/local /pgsql/bin/data
su - postgres
/usr/local/pgsql/bin/initdb -D /usr/local/pgsql/data
/usr/local/pgsql/bin/postgres -D /usr/local/pgsql/data
/usr/local/pgsql/bin/createdb test
/usr/local/pgsql/bin/psql test

At this time we are sure that postgres is working properly and we are ready to start Slony-I with its installation. In terminal move to the directory of Slony-I code and configure installation by
$ ./configure --with-pgsourcetree=\home\mudaser\Downloads\postgresql-4.4.0

Now here It should be informed that there is another way of specifying the directories, that is, individually assigning parameters to -with-pgconfigdi , –with-pgbindir, –with-pgincludedir, –with-pgincludeserverdir, –with-pglibdir, –with-pgpkglibdir, –with-pgsharedir. In order to locate these directories accurately pg_config package. Pg_config might not be installed already so get it from apt-get install libpq-dev. Now find the all the directories of postgres by ‘pg_config’ command. You can learn about pg_config by its help manual or from here

A sample configure command in this case would look like :
$ ./configure --with-pgconfigdir=/etc/postgresql/8.4/main --with-pgbindir=/usr/lib/postgresql/8.4/bin --with-pgincludedir=/usr/include/postgresql --with-pgincludeserverdir=/usr/include/postgresql/8.4/server --with-pglibdir=/usr/lib/ --with-pgpkglibdir=/usr/lib/postgresql/8.4/lib --with-pgsharedir=/usr/share/postgresql/8.4
A proper configuration would look like this one:

./configure 
checking build system type... i686-pc-linux-gnu
checking host system type... i686-pc-linux-gnu
checking which template to use... linux
configure: using CFLAGS=
checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables... 
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether gcc accepts -g... yes
checking for gcc option to accept ISO C89... none needed
checking for ld used by GCC... /usr/bin/ld
checking if the linker (/usr/bin/ld) is GNU ld... yes
checking for perl... /usr/bin/perl
checking for tar... /bin/tar
checking for flex... flex
checking for bison... bison -y
checking for sed... sed
checking for the pthreads library -lpthreads... no
checking whether pthreads work without any flags... no
checking whether pthreads work with -Kthread... no
checking whether pthreads work with -kthread... no
checking for the pthreads library -llthread... no
checking whether pthreads work with -pthread... yes
checking for joinable pthread attribute... PTHREAD_CREATE_JOINABLE
checking if more special flags are required for pthreads... no
checking for cc_r... gcc
checking how to run the C preprocessor... gcc -E
checking for grep that handles long lines and -e... /bin/grep
checking for egrep... /bin/grep -E
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... yes
checking for inttypes.h... yes
checking for stdint.h... yes
checking for unistd.h... yes
checking fcntl.h usability... yes
checking fcntl.h presence... yes
checking for fcntl.h... yes
checking limits.h usability... yes
checking limits.h presence... yes
checking for limits.h... yes
checking stddef.h usability... yes
checking stddef.h presence... yes
checking for stddef.h... yes
checking sys/socket.h usability... yes
checking sys/socket.h presence... yes
checking for sys/socket.h... yes
checking sys/time.h usability... yes
checking sys/time.h presence... yes
checking for sys/time.h... yes
checking for inttypes.h... (cached) yes
checking for gettimeofday... yes
checking for dup2... yes
checking for alarm... yes
checking for memset... yes
checking for select... yes
checking for strdup... yes
checking for strerror... yes
checking for strtol... yes
checking for strtoul... yes
checking for int32_t... yes
checking for uint32_t... yes
checking for u_int32_t... yes
checking for int64_t... yes
checking for uint64_t... yes
checking for u_int64_t... yes
checking for ssize_t... yes
checking for POSIX signal interface... yes
checking if you have requested slony1-engine building... yes
checking for pg_config... /usr/local/pgsql/bin/pg_config
pg_config says pg_bindir is /usr/local/pgsql/bin/
pg_config says pg_libdir is /usr/local/pgsql/lib/
pg_config says pg_includedir is /usr/local/pgsql/include/
pg_config says pg_pkglibdir is /usr/local/pgsql/lib/
pg_config says pg_includeserverdir is /usr/local/pgsql/include/server/
checking for correct version of PostgreSQL... 8.4
8.4
pg_config says pg_sharedir is /usr/local/pgsql/share/
checking for PQunescapeBytea in -lpq... yes
checking libpq-fe.h usability... yes
checking libpq-fe.h presence... yes
checking for libpq-fe.h... yes
checking postgres.h usability... yes
checking postgres.h presence... yes
checking for postgres.h... yes
checking for utils/typcache.h... yes
checking for plpgsql.so... yes
checking for postgresql.conf.sample... skipped due to override
checking for PQputCopyData in -lpq... yes
checking for PQsetNoticeReceiver in -lpq... yes
checking for PQfreemem in -lpq... yes
checking for typenameTypeId... checking for typenameTypeId... yes, and it takes 3 arguments
checking for GetActiveSnapshot... yes
checking for standard_conforming_strings... yes
checking whether GetTopTransactionId is declared... yes
checking if you have requested documentation building... no
configure: creating ./config.status
config.status: creating Makefile.global
config.status: WARNING:  Makefile.global.in seems to ignore the --datarootdir setting
config.status: creating GNUmakefile
config.status: creating slony1.spec
config.status: creating Makefile.port
config.status: creating config.h
config.status: config.h is unchanged

# make all
make[1]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/parsestatements'
./test-scanner < /dev/null > emptytestresult.log
cmp ./emptytestresult.log emptytestresult.expected
./test-scanner < ./test_sql.sql > test_sql.log
cmp ./test_sql.log ./test_sql.expected
./test-scanner < ./cstylecomments.sql > cstylecomments.log
cmp ./cstylecomments.log ./cstylecomments.expected
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/parsestatements'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/slon'
make[2]: Nothing to be done for `all'.
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/slon'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/slonik'
make[2]: Nothing to be done for `all'.
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/slonik'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/backend'
make[2]: Nothing to be done for `all'.
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/backend'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/ducttape'
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/ducttape'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/slony_logshipper'
bison -y -d  parser.y
mv -f y.tab.c parser.c
flex  -o'scan.c' scan.l
scan.l:438: warning, rule cannot be matched
gcc -g -O2 -Wall -Wmissing-prototypes -Wmissing-declarations -I../.. -DPGSHARE="\"/usr/local/pgsql/share/\""  -I/usr/local/pgsql/include/ -I/usr/local/pgsql/include/server/  -c -o parser.o parser.c
gcc -g -O2 -Wall -Wmissing-prototypes -Wmissing-declarations -I../.. -DPGSHARE="\"/usr/local/pgsql/share/\""  slony_logshipper.o dbutil.o ipcutil.o parser.o  ../parsestatements/scanner.o -L/usr/local/pgsql/lib/ -L/usr/local/pgsql/lib/ -lpq  -Wl,-rpath,/usr/local/pgsql/lib/ -o slony_logshipper
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/slony_logshipper'
make[1]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src'
make[1]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/tools'
for subdir in altperl ; do \
          make -C $subdir all || exit; \
        done
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/tools/altperl'
make[2]: Nothing to be done for `all'.
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/tools/altperl'
make[1]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/tools'
All of Slony-I is successfully made. Ready to install

# make install
make[1]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/parsestatements'
make[2]: Nothing to be done for `install'.
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/parsestatements'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/slon'
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs /usr/local/pgsql/bin/
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/install-sh -c -m 755 slon /usr/local/pgsql/bin/
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/slon'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/slonik'
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs /usr/local/pgsql/bin/
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/install-sh -c -m 755 slonik /usr/local/pgsql/bin/
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/slonik'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/backend'
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs /usr/local/pgsql/lib/
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs /usr/local/pgsql/share/
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/install-sh -c -m 755 slony1_funcs.so /usr/local/pgsql/lib/
for file in slony1_base.sql slony1_funcs.sql slony1_base.v83.sql slony1_funcs.v83.sql; do \
	  /bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/install-sh -c -m 644 $file /usr/local/pgsql/share/ || exit ; \
	done
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/backend'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/ducttape'
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs 
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/ducttape'
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/src/slony_logshipper'
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs /usr/local/pgsql/bin/
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/install-sh -c -m 755 slony_logshipper /usr/local/pgsql/bin/
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src/slony_logshipper'
make[1]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/src'
make[1]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/tools'
for subdir in altperl ; do \
          make -C $subdir install || exit; \
        done
make[2]: Entering directory `/home/mudaser/Downloads/slony1-2.0.0/tools/altperl'
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs /usr/local/etc
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs /usr/local/pgsql/lib/
/bin/sh /home/mudaser/Downloads/slony1-2.0.0/config/mkinstalldirs 
The altperl tools won't be installed unless --with-perltools is specified in configure
make[2]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/tools/altperl'
make[1]: Leaving directory `/home/mudaser/Downloads/slony1-2.0.0/tools'
All of Slony-I is successfully installed

Backup

In Point-in-Time recovery we need to first get a backup of segment files of WAL and then run the server in recovery mode. For the backup part we will use a simple linux copy command for copying the files to a folder outside the data directory of postgresql.

Now In order to move Postgres recovery mode, we have to alter its configuration file — postgresql.conf.

I worked on different versions of postgres; sometimes with the same version with different installation options. The location of different directories is heavily dependent on the individual setup.

I found mine at /etc/postgresql/8.4/main and on one of the other version of postgresql it was located at /opt/Postgres/8.4/data. In general, you can use locate or find commands to find the configuration files and then follow the rest of the tutorial.

Now, we have to edit postgresql.conf (through sudo, if needed). Go to the archiving portion of it and uncomment a lines. You will also need to make some changes. At the end, it should look something like this:

# - Archiving -
archive_mode = on        
# allows archiving to be done
# (change requires restart)
archive_command = 'cp %p /mnt/backup/%f'        
# command to use to archive a logfile segment;
archive_timeout = 30          
# force a logfile segment switch after this
# number of seconds; 0 disables

Note: /mnt/backup is the directory i want the backup to be stored. The two Variables %p and %f will be replaced automatically by the server when backup is performed: %p would be the directory of data cluster and %f would be the name of backup file.

We are done with the prerequisites and now in order start the backup, we have to switch to psql console and commit following commands.

# SELECT pg_start_backup('MY BACKUP_1')

it will will show something like this

pg_start_backup
-----------------
0/7000020
(1 row)

The backup of WAL segment files is started and the files from pg_xlog are been copied to /mnt/backup/

In order to stop the backup:

# SELECT pg_stop_backup()
pg_stop_backup
----------------
0/7000080
(1 row)

This shows the backup process is successfully closed.

Important Note: The directory /mnt/backup should have permission for postgres user to read and write (owner). Otherwise, you get an error like this at runtime (as seen in the log file):

2010-08-11 21:54:46 PKST LOG:  archive command failed with exit code 1
2010-08-11 21:54:46 PKST DETAIL:  
The failed archive command was: cp pg_xlog/000000010000000000000000 /mnt/backup/000000010000000000000000
cp: cannot create regular file `/mnt/backup/000000010000000000000000': Permission denied

Recovery

So now comes the recovery part, much easier than i thought but a little bit tricky. In order to continue with Point-in-Time recovery we first create a file named ‘Recovery.conf’ and place it in the data cluster, which in my case was /var/lib/postgresql/8.4/main

So what does the recovery file contains. Actually it has just another copy command for copying back files to data cluster from backup directory(this will be opposite to the previous backup command).

restore_command = 'cp /mnt/backup/%f "%p"'

When the recovery gets completed, postgresql will rename ‘recovery.conf’ to ‘recovery.done’.

Now stop the server by /init.d/postgresql-8.4 stop. We presume that there was a database crash down all the information in the data directory is lost. After which we will let postgresql to recover the files from the backup directory.

The next step is to delete files from the pg_xlog directory.

Now start the server by writing in terminal /init.d/postgresql-8.4 start which will automatically trigger a recovery. So what happened is that postgresql server found a recovery.conf thus shifted to its recovery mode.

You can assure proper recovery by checking the name of the recovery.conf file and by looking at the log of postgresql server. The log would Look Like this:

2010-08-12 12:29:06 PKST LOG:  database system is shut down
2010-08-12 12:29:48 PKST LOG:  database system was shut down at 2010-08-12 12:29:06 PKST
2010-08-12 12:29:48 PKST LOG:  creating missing WAL directory "pg_xlog/archive_status 
2010-08-12 12:29:48 PKST LOG:  starting archive recovery
2010-08-12 12:29:48 PKST LOG:  restore_command = 'cp /mnt/backup/%f %p'
2010-08-12 12:29:48 PKST LOG:  automatic recovery in progress
2010-08-12 12:29:48 PKST LOG:  record with zero length at 0/A000064
2010-08-12 12:29:48 PKST LOG:  redo is not required
2010-08-12 12:29:48 PKST LOG:  selected new timeline ID: 2
2010-08-12 12:29:49 PKST LOG:  archive recovery complete
2010-08-12 12:29:49 PKST LOG:  autovacuum launcher started
2010-08-12 12:29:49 PKST LOG:  database system is ready to accept connections

Some useful links you might want to refer to:

http://developer.postgresql.org/pgdocs/postgres/continuous-archiving.html#BACKUP-ARCHIVING-WAL

http://scale-out-blog.blogspot.com/2009/02/simple-ha-with-postgresql-point-in-time.html

http://www.mkyong.com/database/postgresql-point-in-time-recovery-incremental-backup/

But here he is.. out of thoughts.. out of memory.. it’s not a shock, not even a nightmare.. it’s something he always waited for.. and when he got it, he thought it, that he would sort it, Cuz this is everything he ever wanted..

Flash of light, and he’s been taken to a place, never seen before.. blue is the sky and its dark, but things are still visible around.. Looks like an empty town, there are houses but no people, there is a park but no one playing in it, there is shop but no one srounding it.. He’s walking, and only the sound of his steps is audible, making the surround more strange then it already is..

Flash of light and he’s taken back to his room, high breath, fully open eyes, shocked faced with sign of fright on it, all alone, lying on his bed, trying to ignore what happened.. wind is blowing out side, making the curtains move slightly.. shivering body, he tries to get up.. but it seems too hard for him…

Getting up he moved towards the window.. staring outside the window.. he notices, the time is still.. no one is around.. things have stopped moving.. “whats all this.. its not real. It is not suppose to be.. what is it.. is it dawn.. or is it dusk..”