table of contents
slony_logshipping(1) | Slony-I 2.2.10 Documentation | slony_logshipping(1) |
NAME¶
slony_logshipping - slony_logshippping daemon
slony_logshipper TOOL ¶
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¶
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- Options, chosen from the following:
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- h
display this help text and exit
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- v
display program version and exit
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- q
quiet mode
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- l
cause running daemon to reopen its logfile
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- r
cause running daemon to resume after error
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- t
cause running daemon to enter smart shutdown mode
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- T
cause running daemon to enter immediate shutdown mode
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- c
destroy existing semaphore set and message queue (use with caution)
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- f
stay in foreground (don't daemonize)
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- w
enter smart shutdown mode immediately
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- A specified log shipper configuration file
This configuration file consists of the following specifications:
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- logfile = './offline_logs/logshipper.log';
Where the log shipper will leave messages.
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- cluster name = 'T1';
Cluster name
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- 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.
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- 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.
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- destination dir = './offline_result';
If specified, the log shipper will write the results of data massaging into result logfiles in this directory.
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- max archives = 3600;
This fights eventual resource leakage; the daemon will enter ‘smart shutdown’ mode automatically after processing this many archives.
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- ignore table "public"."history";
One may filter out single tables from log shipped replication
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- ignore namespace "public";
One may filter out entire namespaces from log shipped replication
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- rename namespace "public"."history" to
"site_001"."history";
One may rename specific tables.
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- rename namespace "public" to "site_001";
One may rename entire namespaces.
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- post processing command = 'gzip -9 $inarchive';
Pre- and post-processing commands are executed via system(3).
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:
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- $inarchive - indicating incoming archive filename
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- $outnarchive - indicating outgoing archive filename
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- error command = ' ( echo "archive=$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.
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- Archive File Names
Each filename is added to the SystemV Message queue for processing by a slony_logshipper process.
18 January 2021 |