slony_logshipper is a tool designed to help apply logs. It runs as a daemon and scans the archive directory for new .SQL files which it then applies to the target database. It can be run with three sorts of parameters:
Options, chosen from the following:
display this help text and exit
display program version and exit
cause running daemon to reopen its logfile
cause running daemon to resume after error
cause running daemon to enter smart shutdown mode
cause running daemon to enter immediate shutdown mode
destroy existing semaphore set and message queue (use with caution)
stay in foreground (don't daemonize)
enter smart shutdown mode immediately
A specified log shipper configuration file
This configuration file consists of the following specifications:
logfile = './offline_logs/logshipper.log';
Where the log shipper will leave messages.
cluster name = 'T1';
destination database = 'dbname=slony_test3';
Optional conninfo for the destination database. If given, the log shipper will connect to this database, and apply logs to it.
archive dir = './offline_logs';
The archive directory is required when running in "database-connected" mode to have a place to scan for missing (unapplied) archives.
destination dir = './offline_result';
If specified, the log shipper will write the results of data massaging into result logfiles in this directory.
max archives = 3600;
This fights eventual resource leakage; the daemon will enter "smart shutdown" mode automatically after processing this many archives.
ignore table "public"."history";
One may filter out single tables from log shipped replication
ignore namespace "public";
One may filter out entire namespaces from log shipped replication
rename namespace "public"."history" to "site_001"."history";
One may rename specific tables.
rename namespace "public" to "site_001";
One may rename entire namespaces.
post processing command = 'gzip -9 $inarchive';
Pre- and post-processing commands are executed via
An "@" as the first character causes the exit code to be ignored. Otherwise, a nonzero exit code is treated as an error and causes processing to abort.
Pre- and post-processing commands have two further special variables defined:
$inarchive - indicating incoming archive filename
$outnarchive - indicating outgoing archive filename
error command = ' ( echo "archive=$inarchive" echo "error messages:" echo "$errortext" ) | mail -s "Slony log shipping failed" postgres@localhost ';
The error command indicates a command to execute upon encountering an error. All logging since the last successful completion of an archive is available in the $errortext variable.
In the example shown, this sends an email to the DBAs upon encountering an error.
Archive File Names
Each filename is added to the SystemV Message queue for processing by a slony_logshipper process.