BLOBs include the LONG VARCHAR, LONG BINARY, TEXT, and IMAGE data types.
When SQL Remote replicates an INSERT or UPDATE statement, it uses a variable in place of the BLOB value. That is, the BLOB is broken into pieces and replicated in chunks. At the recipient database, the pieces are reconstituted by using a SQL variable and concatenated. The value of the variable is built up by a sequence of statements of the form:
SET vble = vble || 'more_stuff';
The variable makes the size of the SQL statements involving long values smaller, so they fit within a single message.
The SET statements are separate SQL statements, so that the BLOB is effectively split over several SQL Remote messages.
Discuss this page in DocCommentXchange.
|Copyright © 2010, iAnywhere Solutions, Inc. - SQL Anywhere 12.0.0|