Frext architecture
In short, this is how Frext works: a change on the master database is
recorded in a log table, an agent converts the change into a file
message. An agent from the remote database picks up this file and
executes SQL commands against the remote database, thus replicating the
data change.
Description
Described is a complete replication cycle between two
databases.
- (On the sending database)
- Recording.
A operation, e.g. insert, update or delete is recorded in the
Frext transaction log
- Generating
messages. An agent scans the transaction log for non
replicated changes and produces messages in the Frext message table
- Writing
messages to files. Each message containing a change or
group of changes (transaction) is converted to a file by the
agent; the file contains all information for compiling SQL
commands (but without containing the actual SQL command)
- File(s) is
transported
(copied) to the remote location
- (On the receiving or remote database)
- Importing
messages files. The agent for the remote database reads
the message file(s) into the database
- Applying
messages. Every message will be applied, i.e. the
agent compiles SQL commands; SQL commands are executed against the
remote databases, thus replicating the data change enforced
the
the master database
- Writing
confirmations. After applying, a conformation message
is written; this is transported back to the receiver and read in by the
receiver
- File(s) is
transported
(copied) to the sender location
- (On the sending database)
- Read confirmations.
- Apply confirmations.
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