Library Version 11.2.5.3

Library Version 12.1.6.1

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Ex_rep_chan: a Replication Manager -channel example			Ex_rep_chan: a Replication Manager channel example
Prev	Chapter 12. - Berkeley DB Replication -	Chapter 12. Berkeley DB Replication	Next

@@ -35,156 +32,157 @@ channel example

Ex_rep_chan: a Replication Manager -channel example

Ex_rep_chan: a Replication Manager channel example

- Ex_rep_chan, found in the examples/c/ex_rep_chan - subdirectory of the Berkeley DB distribution, is a simple but complete - demonstration of a replicated application that uses the Replication - Manager feature of channels to perform write forwarding. The - application is a mock stock ticker. Although similar to the ex_rep_mgr - example program, this example differs in that it provides an example of - using Replication Manager message channels. Any site accepts a command - to write data to the database. If the site is a client, then, using - the channels feature, the application forwards the request to the - master site. If the site is a master then the request is automatically - handled locally. You can read and write stock values at any site - without needing to know what site is currently the master. -

+ Ex_rep_chan, found in the + examples/c/ex_rep_chan subdirectory + of the Berkeley DB distribution, is a simple but complete + demonstration of a replicated application that uses the + Replication Manager feature of channels to perform write + forwarding. The application is a mock stock ticker. Although + similar to the ex_rep_mgr example program, this example + differs in that it provides an example of using Replication + Manager message channels. Any site accepts a command to write + data to the database. If the site is a client, then, using the + channels feature, the application forwards the request to the + master site. If the site is a master then the request is + automatically handled locally. You can read and write stock + values at any site without needing to know what site is + currently the master. +

- The set of supported commands can be viewed with either the - help or the - ? command. Several commands work with - key/data pairs where the key is a stock symbol and the data is its - value. -

+ The set of supported commands can be viewed with either the + help or the ? command. Several commands work + with key/data pairs where the key is a stock symbol and the + data is its value. +

- The command to retrieve and print the current site's database contents - is print or simply an empty input - line. To read the contents of the master's database from any site use - the get key key ... command. That - command will forward the read request to the master if necessary and - return the key/data pairs for all given keys. -

+ The command to retrieve and print the current site's + database contents is print or + simply an empty input line. To read the contents of the + master's database from any site use the get key key ... + command. That command will + forward the read request to the master if necessary and return + the key/data pairs for all given keys. +

+ There are two commands to put data into the database. Both + commands take one or more key/data pairs, all of which are + written into the database in a single transaction at the + master site. The put command + sends the data to the master site, and simply waits for a + status response. The put_sync + command sends the data to the master site, and uses a + transaction token returned by the master to wait for the + contents of that put to be available on the local site. This + serves as a demonstration of the read + your writes consistency feature. +

+ The Makefile created by the standard UNIX configuration + will build the ex_rep_chan example on most platforms. Enter + "make ex_rep_chan" to build it. +

- There are two commands to put data into the database. Both commands - take one or more key/data pairs, all of which are written into the - database in a single transaction at the master site. The - put command sends the data to the - master site, and simply waits for a status response. The - put_sync command sends the data to the - master site, and uses a transaction token returned by the master to - wait for the contents of that put to be available on the local - site. This serves as a demonstration of the - read your writes consistency feature. -

+ The synopsis for the program is as follows: +

- The Makefile created by the standard UNIX configuration will build the - ex_rep_chan example on most platforms. Enter "make ex_rep_chan" to - build it. -

ex_rep_chan -h home
+        -l host:port [-MC] [-r
+        host:port] [-R
+        host:port] [-p
+        priority] [-v]

- The synopsis for the program is as follows: -

-ex_rep_chan -h home -l host:port [-MC] [-r host:port] [-R host:port] [-p priority] [-v] -

- The options are as follows: -

+ The options are as follows: +

- - -h - + -h: Specify a home directory for the database environment.; + Specify a home directory for the database + environment. +
- - -l - + -l: Listen on local host "host" at port "port" for incoming connections.; + Listen on local host "host" at port "port" for + incoming connections. +
- - -M - + -M: Configure this process as a master.; + Configure this process as a master. +
- - -C - + -C: Configure this process as a client.; + Configure this process as a client. +
- - -r - + -r: - Identifies the helper site used for joining the group. -
- - -R - + -R: - Identifies a remote peer to be used for joining the group. This - peer is used for syncing purposes. See - Client-to-client synchronization - for more information. -; + Identifies a remote peer to be used for joining + the group. This peer is used for syncing purposes. See + Client-to-client synchronization for more + information. +
- - -p - + -p: - Set the election priority. See - Elections for more - information. -; + Set the election priority. See Elections + for more information. +
- - -v - + -v: - Indicates that additional informational and debugging output - should be enabled. -

- A typical ex_rep_chan session begins with a command such as the - following, to start a master: -

+ A typical ex_rep_chan session begins with a command such as + the following, to start a master: +

ex_rep_chan -M -h DIR1 -l localhost:30100

- and several clients: -

+ and several clients: +

ex_rep_chan -C -h DIR2 -l localhost:30101 -r localhost:30100
 ex_rep_chan -C -h DIR3 -l localhost:30102 -r localhost:30100
 ex_rep_chan -C -h DIR4 -l localhost:30103 -r localhost:30100

@@ -200,13 +198,12 @@ ex_rep_chan -C -h DIR4 -l localhost:30103 -r localhost:30100 Next - Ex_rep_base: putting it all together + Ex_rep_base: putting it all + together Home - Chapter 13. - Distributed Transactions - + Chapter 13. Distributed Transactions