installing postgreSQL on leopard thru MacPorts

this is my first time installing postgreSQL on Mac OS X and i'm happy to say that it was successful.

i have to tweak some more things though, like allowing remote login (ssh) for the "postgres" account. i'll post the solution once i solve this problem.

i have installed postgreSQL before in redhat, MS$ and ubuntu by source (make, make install..) and by package but never tried installing it thru BSD "ports". there's always a first time so might as well post how i did it.

since leopard is built on Darwin, guys from MacPorts ported the BSD Ports to the latest OS X. this made life easier for me since i'm fairly new to OS X and it takes care of the dependencies.

specs:
MacBook Pro
Mac OS X, Version 10.5.5 (Darwin 9.5)
2.6GHz Intel Core 2 Duo
4GB 667 MHz DDR2 SDRAM

steps:
1] if you haven't installed MacPorts yet, install it first. you can find a pretty intensive guide at MacPorts Guide.

now don't get too excited and install postgreSQL right away. ensure first that you have the latest ports by doing:

sudo port -d selfupdate

2] search for the postgres ports by:

port search postgresql

search results:

postgresql7 databases/postgresql7 7.4.21 The most advanced open-source database available anywhere
postgresql80 databases/postgresql80 8.0.18 The most advanced open-source database available anywhere
postgresql80-doc databases/postgresql80-doc 8.0.18 Documentation for the postgresql database
postgresql80-server databases/postgresql80-server 8.0.18 run postgresql80 as server
postgresql81 databases/postgresql81 8.1.14 The most advanced open-source database available anywhere
postgresql81-doc databases/postgresql81-doc 8.1.14 Documentation for the postgresql database
postgresql81-server databases/postgresql81-server 8.1.14 run postgresql81 as server
postgresql82 databases/postgresql82 8.2.10 The most advanced open-source database available anywhere
postgresql82-doc databases/postgresql82-doc 8.2.10 Documentation for the postgresql database
postgresql82-server databases/postgresql82-server 8.2.10 run postgresql82 as server
postgresql83 databases/postgresql83 8.3.4 The most advanced open-source database available anywhere.
postgresql83-doc databases/postgresql83-doc 8.3.4 Documentation for the postgresql database
postgresql83-server databases/postgresql83-server 8.3.4 run postgresql83 as server
postgresql_autodoc databases/postgresql_autodoc 1.25 Automatic documentation generator for postgresql databases
caml-postgresql devel/caml-postgresql 1.8.2 OCaml-interface to the PostgreSQL-database
postgresql-jdbc java/postgresql-jdbc 8.0-311 PostgreSQL JDBC driver
py-postgresql-exception python/py-postgresql-exception 0.2 exceptions for the py-postgresql modules
py-postgresql-greentrunk python/py-postgresql-greentrunk 0.1 greentrunk interface to postgresql
py-postgresql-layout python/py-postgresql-layout 0.3 layout for the py-postgresql modules
py-postgresql-pqueue python/py-postgresql-pqueue 0.1 pure python implementation of the pq protocol
py-postgresql-proboscis python/py-postgresql-proboscis 0.1 postgresql database connector in pure python

3] install the latest version 8.3.4:

sudo port install postgresql83 postgresql83-server

or if with documentation:

sudo port install postgresql83 postgresql83-server postgresql83-doc

i can't say how long the installation will take, i left mine overnight..at the end it will spew out this message:

###########################################################
# A startup item has been generated that will aid in
# starting postgresql83-server with launchd. It is disabled
# by default. Execute the following command to start it,
# and to cause it to launch at startup:
#
# sudo launchctl load -w /Library/LaunchDaemons/org.macports.postgresql83-server.plist
###########################################################
---> Installing postgresql83-server 8.3.4_0

To create a database instance, after install do
sudo mkdir -p /opt/local/var/db/postgresql83/defaultdb
sudo chown postgres:postgres /opt/local/var/db/postgresql83/defaultdb
sudo su postgres -c '/opt/local/lib/postgresql83/bin/initdb -D /opt/local/var/db/postgresql83/defaultdb'

To tweak your DBMS, consider increasing kern.sysv.shmmax by adding an increased kern.sysv.shmmax .. to /etc/sysctl.conf
---> Activating postgresql83-server 8.3.4_0
---> Cleaning postgresql83-server

4] if you want postgres to start everytime you power on your mac then by all means:

sudo launchctl load -w /Library/LaunchDaemons/org.macports.postgresql83-server.plist

note: this is optional. you can start/stop postgres manually.

5] create directory for you database "defaultdb":

sudo mkdir -p /opt/local/var/db/postgresql83/defaultdb

note: don't fret if you don't have the directories yet.. "-p" option of mkdir will create the directories in the specified path. you can also change the "defaultdb" to whichever name you like for your database.

6] change ownership of folder "defaultdb" to postgres

sudo chown postgres:postgres /opt/local/var/db/postgresql83/defaultdb

note: looking at the command above "chown postgres:postgres" means that the "postgres" user need not be created manually. it was already created while installing.

7] initialize "defaultdb" database:

sudo su postgres -c '/opt/local/lib/postgresql83/bin/initdb -D /opt/local/var/db/postgresql83/defaultdb'

8] there are two ways to install pgAdmin - by MacPorts or just download pgAdmin3 1.8.4 dmg image here

below are my own "tweaking" steps..

9] i can't create files at postgres home folder so:

sudo chown postgres:postgres /opt/local/var/db/postgresql83/

note: i said home folder since when i do a "sudo su - postgres" and "pwd" i find myself in "/opt/local/var/db/postgresql83/". "su -" will change directory to target postgres' home directory. RTM.

10] change password of postgres account:

sudo passwd postgres

11] i know i'm lazy so i proceeded on creating a ".profile" at postgres' home directory:

a] switch to user postgres

su - postgres

b] create .profile file to add "/opt/local/lib/postgresql83/bin/" to $PATH and some alias

vi .profile

export PATH=/opt/local/bin:/opt/local/sbin:/opt/local/lib/postgresql83/bin/:$PATH
export MANPATH=/opt/local/share/man:$MANPATH

alias ll='ls -alhG'
alias lf='ls -alhFG'

12] run .profile by

. .profile

13] now i can issue postgres commands like psql, createdb, createuser without specifying the full path of the executables. make a test database:

createdb test

14] create language plpgsql in template1:

createlang -U postgres plpgsql template1

15] i always use the contrib dblink. contribs are usually at the "share" folder so after searching i was able to locate it at "macports/software" directories. to create "dblink" functions in "test" database.

psql test < /opt/local/var/macports/software/postgresql83/8.3.4_0/opt/local/share/postgresql83/contrib/dblink.sql

16] edit pg_hba.conf

vi defaultdb/pg_hba.conf

17] allow incoming connections from our LAN. CIDR-ADDRESS column will depend on your subnet. YMMV. in my case:

host all all 172.20.0.0/16 md5

note: i chose "md5" authentication. if you don't know what you're doing just substitute this with "trust".

18] edit postgresql configuration file postgresql.conf:

vi defaultdb/postgresql.conf

19] update or uncomment the following lines:

listen_addresses = '*'
log_destination = 'syslog'
log_rotation_size = 10MB
syslog_facility = 'LOCAL0'
syslog_ident = 'postgres'
log_hostname = on

20] updating pg_hba.conf and postgresql.conf requires restarting postgres. if you're in postgres' home directory issue:

pg_ctl stop -D defaultdb

then

pg_ctl start -D defaultdb

21] create a non superuser. this one i'm going to use for my web applications.

createuser -P -e pgapache

Enter password for new role:
Enter it again:
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) n
Shall the new role be allowed to create more new roles? (y/n) n
CREATE ROLE pgapache PASSWORD 'md575f98f7f3815db249340343362e00568' NOSUPERUSER NOCREATEDB NOCREATEROLE INHERIT LOGIN;

that's pretty much what i've done with my postgreSQL installation.. enjoy.

Savepoints inside Transactions

while working on a script, i discovered how to use SAVEPOINTS inside a PostgreSQL Transaction.

typical PostgreSQL Transactions looks like this:

BEGIN;
INSERT/UPDATE/DELETE STATEMENTS;
IF ERROR THEN
ROLLBACK;
ELSE
COMMIT;
END IF;

sample postgreSQL Transaction with SAVEPOINT:

BEGIN;
SAVEPOINT my_svpnt;
INSERT STATEMENT 1;
IF ERROR THEN
ROLLBACK TO SAVEPOINT my_svpnt;
END IF;
INSERT STATEMENT 2;
RELEASE SAVEPOINT my_svpnt;
COMMIT;

what do you do if you want to commit some statements or just ignore some errors before committing everything? knowing that inside a transaction all succeeding statements after an error will be ignored.

sample scenario:

loop thru checkboxes from a HTML POST then INSERT or UPDATE rows.
problem then arises because i am too lazy to write long PHP codes -- i don't want to check each rows from a HTML POST to determine if what i need to do is INSERT or UPDATE. that is, to INSERT if the row doesn't exist or UPDATE if it exist.

there's an easy way, i can check the primary key -- i don't want to do that either.

i need to know if transactions can be done in such a way where i can decide which statements to commit.

test first if each rows exists in the table:

// begin postgreSQL transaction
$conn->execute('BEGIN');
// loop thru checkboxes, rows from HTML POST
FOR ($i = 0; $i <= $rownum; $i++) {  // check if checkbox is checked
IF ($checkbox[$i] == 1) {
// check if row exist or is not yet in the table
$checkRowSQL = "SELECT * FROM pay_schedule             
                WHERE
                pay_schedule_id = {$n_pay_schedule_id[$i]}";
// pg_query
$rsChk = $conn->execute($checkRowSQL);
// get result set from SELECT query
$result->set_resultset($rsChk);
// EOF() - SELECT returns 0 rows then INSERT new row
IF ($result->EOF()) {
$sql = "INSERT INTO pay_schedule
    (pay_schedule_code, pay_schedule_remarks, pay_schedule_schedule_id)
    VALUES
    ('$s_pay_schedule_code','$n_pay_schedule_remarks[$i]', $n_pay_schedule[$i])";
$rs = $conn->execute($sql);
// if INSERT returns an error, break from FOR loop
IF (!$rs) {
$header = 'Unable to Insert Pay Scheme';
$message = 'Check entries...';
break;
}
// not EOF() - SELECT returns a row then UPDATE row
} ELSE {
$sql = "UPDATE pay_schedule SET
          pay_schedule_code = '{$s_pay_schedule_code}',
          pay_schedule_remarks = '{$n_pay_schedule_remarks[$i]}',
          pay_schedule_schedule_id = {$n_pay_schedule[$i]}
          WHERE
          pay_schedule_id = {$n_pay_schedule_id[$i]}";
$rs = $conn->execute($sql);
IF (!$rs) {
// if UPDATE returns an error, break from FOR loop
$header = 'Unable to Update Pay Scheme';
$message = 'Check entries...';
break;
}
}
}
}
// no error then COMMIT everything
IF ($rs) {
$conn->execute('COMMIT');
$header = 'Update/Add Confirmation';
$message = 'Pay Scheme Updated/Added';
// if there's an error then ROLLBACK all changes
} ELSE {
$conn->execute('ROLLBACK');
}
$commandname = 'Ok';
$command = 'fnReturn()'; // return to original page

using SAVEPOINT my code looks like this:

// begin postgreSQL transaction
$conn->execute('BEGIN');
// loop thru checkboxes, rows from HTML POST
FOR ($i = 0; $i <= $rownum; $i++) { // check if checkbox is checked 
if ($checkbox[$i] == 1) {
// establish a SAVEPOINT
$conn->execute('SAVEPOINT bgn_svpnt');
// try to INSERT row
$sql = "INSERT INTO pay_schedule
   (pay_schedule_code, pay_schedule_remarks, pay_schedule_schedule_id)
   VALUES
   ('$s_pay_schedule_code','$n_pay_schedule_remarks[$i]', $n_pay_schedule[$i])";
// pg_query
$rs = $conn->execute($sql);
/* if INSERT error, i.e duplicate row or constraint violation
     do a ROLLBACK TO bgn_svpnt savepoint then UPDATE existing row
  */
IF (!$rs) {
$conn->execute('ROLLBACK TO SAVEPOINT bgn_svpnt');
$sql = "UPDATE pay_schedule SET
         pay_schedule_code = '{$s_pay_schedule_code}',
         pay_schedule_remarks = '{$n_pay_schedule_remarks[$i]}',
         pay_schedule_schedule_id = {$n_pay_schedule[$i]}
         WHERE
         pay_schedule_id = {$n_pay_schedule_id[$i]}";
$rs = $conn->execute($sql);
// if ERROR still then cancel FOR loop and ROLLBACK everything
IF (!$rs) {
$header = 'Unable to Update Pay Scheme';
$message = 'Check entries...';
break;
}
}
// good to do a RELEASE if savepoint is not needed anymore
$conn->execute('RELEASE SAVEPOINT bgn_svpnt');
}
}
IF ($rs) {
$conn->execute('COMMIT');
$header = 'Update/Add Confirmation';
$message = 'Pay Scheme Updated/Added';
} ELSE {
$conn->execute('ROLLBACK');
}
$commandname = 'Ok';
$command = 'fnReturn()';

i settled with the second code since it will eliminate unnecessary lame SELECTs, wherein i have to retrieve and check result sets.