Using passthrough mode
Thepublisher of the consolidated database can directly intervene at remote
sitesusing a passthrough mode, which enables standard SQL statements to
bepassed through to a remote site.
Determining recipients of
passthroughstatements Passthroughdestinations are determined by sp_passthrough_user and
sp_passthrough_subscription. Executing either of these procedures
determinesa set of recipients for any subsequent passthrough statements.
Executingeither sp_passthrough_user and sp_passthrough_subscription
addsto the current list of recipients. Thesp_passthrough_stop procedure
resetspassthrough (that is, resets the list of recipients to be empty).
InAdaptive Server Enterprise, sp_passthrough never executes statements in
theconsolidated database. PassthroughSQL statements are applied only to
remotedatabases.
Passthroughstatements Tocause passthrough SQL statements to replicate, you call sp_passthrough.
Dueto the VARCHAR(255) limitation in Adaptive Server Enterprise, you
shouldbuild a long SQL statement up in pieces. Callsto
sp_passthrough_piecewill build up a single SQL statement. Calling
sp_passthroughwith the last piece will cause the built up statement to
replicate.
Noteson using
passthroughmode
Youshould always test your passthrough operations on a test database
witha remote database subscribed. Youshould never run untested
passthroughscripts against a production database.
Youshould always qualify object names with the owner name.
PASSTHROUGHstatements are not executed at remote databases from
thesame user ID. Consequently, object names without the owner name
qualifiermay not be resolved correctly.

Schema modifications

TheAdaptive Server Enterprise log transfer interface does not contain
informationabout the number of columns and data types of the columns in a
table. SSREMOTE gets this information directly from the AdaptiveServer
Enterprisesystem tables. Forthis reason, altering a table and then scanning
operationsthat happened before the ALTER TABLE will lead to errors.
SSREMOTEmust set the “truncation point” beyond all operations on
replicatedtables before schema changes can be made. Operationson
replicatedtables need to be prevented between SSREMOTE running and the
schemachanges being made.
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