Aug 6, 2007
Hello,
My company is moving to a SQL Server-based packaged application early next year. We€™re planning our SQL Server architecture but have some questions that I can€™t readily find answers for. I€™m hoping someone here can point me in the right direction.
We have three servers, I€™ll call them A, B, and C. We want to duplicate all changes to certain databases on server A to server B, then duplicate changes to selected databases and tables on server B to server C.
Ideally we€™d run SQL Server 2005 Enterprise Edition on all three servers, but the packaged application vendor does not support SQL Server 2005 yet, only SQL Server 2000. Our license agreement with them does not allow us to use replication on server A. We€™re free to do whatever we want on our other SQL Servers, but server A must sit alone, untouched, like a monolith on a far-away moon. (I€™m lobbying to have the server named Tycho, or TMA2.) Stranger still, they€™re OK with log shipping from server A to other servers. We€™ve tried to explain that replication and log shipping are both core function built into SQL Server, and that if one is acceptable, then both should be. Their fear is that replication could cause performance and stability problems, and to eliminate this possibility they€™re ruling out replication on server A.
Given these constraints we€™re resigned to using SQL Server 2000 Enterprise Edition on servers A and B, and SQL Server 2005 Enterprise Edition on server C. We plan on periodically shipping logs from server A to server B and applying them at server B.
We€™d like to know if it is possible to also use transactional replication on server B to duplicate changes from server B to server C. I€™ve used log shipping and replication in the past, but never at the same time. My understanding is that a database goes into recovery mode while a transaction log is being applied and that any user changes to the database after the log has been applied will cause later log applications to fail. The scripts I€™ve seen that are used to apply the transaction logs put the database into single user mode after the log has been applied to prevent this.
This raises a few questions:
If we try to RESTORE a log to a database being used as a source for transactional replication articles, will the RESTORE fail? Or will the RESTORE start and break the transactional replication? I€™ll test this on my own, but it€™d be nice to know if anyone has already experienced this.
Is it possible for us to have a database in read-only mode serve as the source for transactional replication articles? (I can€™t imagine why not, ever though it seems counter-intuitive - why would you want to replicate transactions from a database that has no transactions?)
If the answer to number two is yes, can we suspend transactional replication on a database, RESTORE a log to the database, put the database into read-only mode after the RESTORE, and restart the replication on the database?
Thanks in advance for sharing your wisdom, everyone!
--
Thomas C. Mueller
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Mar 14, 2006
This thread is no longer active. I moved issue to a new, cleaner thread named: How can I get Transactional Republishing to work?
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I've tried for more than a week to figure this one out, but have not found a solution. I'm missing some critical information that perhaps someone can share. I'm desperate and embarassed that this has kept me stuck for so long. Thanks for any assistance.
In my simplist scenario, I'm transactionally replicating a single table from database A to database B and then from database B to database C. All databases are on the same XP server (in this simplist version of the problem). This is SQL 2005 RTM. Publication A to B replicates fine. Publication B to C can't even get the snapshot to work because I get the error:
Command attempted:
drop Table "dbo"."MyReplTable"
(Transaction sequence number: 0x00004174000000E100A300000000, Command ID: 41)
Error messages:
Cannot drop the table 'dbo.MyReplTable' because it is being used for replication. (Source: MSSQLServer, Error number: 3724) Get help: http://help/3724 (fyi - there is no help here)
I have a simple example script where I've renamed real names to fake names, that is exactly what I run to simulate the problem. Obviously the script is wrong, but where? I used the wizard to create the whole script (I know that is my first mistake ;-) ). After I start the snapshot jobs, I get the error above.
I presume that the sp_addarticle option @pre_creation_cmd = N'drop' is part of the problem. I don't have row filters. Also, I want to be able to replicate schema modifications when necessary (like add a column or drop a column)
Perhaps the sp_addpublication @repl_freq = N'continuous' option in the AtoB publication prevents the BtoC publication from ever getting a chance to do anything, if it never lets go of the table.
If it helps, here is my script with hopefully helpfully renamed objects. My real world scenario has many articles, but this is a simple version - 2 publications each having 1 article (the same table).
/****** Scripting replication configuration for server MyInstance. Script Date: 3/14/2006 11:16:58 AM ******/
/****** Please Note: For security reasons, all password parameters were scripted with either NULL or an empty string. ******/
/****** Installing the server MyInstance as a Distributor. Script Date: 3/14/2006 11:16:58 AM ******/
use master
exec sp_adddistributor @distributor = N'MyInstance', @password = N''
GO
exec sp_adddistributiondb @database = N'distribution', @data_folder = N'C:Program FilesMicrosoft SQL ServerMSSQL.2MSSQLData', @data_file_size = 4, @log_folder = N'C:Program FilesMicrosoft SQL ServerMSSQL.2MSSQLData', @log_file_size = 2, @min_distretention = 0, @max_distretention = 72, @history_retention = 48, @security_mode = 1
GO
use [distribution]
if (not exists (select * from sysobjects where name = 'UIProperties' and type = 'U '))
create table UIProperties(id int)
if (exists (select * from ::fn_listextendedproperty('SnapshotFolder', 'user', 'dbo', 'table', 'UIProperties', null, null)))
EXEC sp_updateextendedproperty N'SnapshotFolder', N'C:ThisFolderMY2005DBWorking
epldata', 'user', dbo, 'table', 'UIProperties'
else
EXEC sp_addextendedproperty N'SnapshotFolder', 'C:ThisFolderMY2005DBWorking
epldata', 'user', dbo, 'table', 'UIProperties'
GO
exec sp_adddistpublisher @publisher = N'MyInstance', @distribution_db = N'distribution', @security_mode = 1, @working_directory = N'C:ThisFolderMY2005DBWorking
epldata', @trusted = N'false', @thirdparty_flag = 0, @publisher_type = N'MSSQLSERVER'
GO
use [DatabaseA]
exec sp_replicationdboption @dbname = N'DatabaseA', @optname = N'publish', @value = N'true'
GO
-- Adding the transactional publication
use [DatabaseA]
exec sp_addpublication @publication = N'PubAtoB', @description = N'Transactional publication of database ''DatabaseA'' from Publisher ''MyInstance''.', @sync_method = N'concurrent', @retention = 0, @allow_push = N'true', @allow_pull = N'true', @allow_anonymous = N'true', @enabled_for_internet = N'false', @snapshot_in_defaultfolder = N'true', @compress_snapshot = N'false', @ftp_port = 21, @ftp_login = N'anonymous', @allow_subscription_copy = N'false', @add_to_active_directory = N'false', @repl_freq = N'continuous', @status = N'active', @independent_agent = N'true', @immediate_sync = N'true', @allow_sync_tran = N'false', @autogen_sync_procs = N'false', @allow_queued_tran = N'false', @allow_dts = N'false', @replicate_ddl = 1, @allow_initialize_from_backup = N'false', @enabled_for_p2p = N'false', @enabled_for_het_sub = N'false'
GO
exec sp_addpublication_snapshot @publication = N'PubAtoB', @frequency_type = 1, @frequency_interval = 0, @frequency_relative_interval = 0, @frequency_recurrence_factor = 0, @frequency_subday = 0, @frequency_subday_interval = 0, @active_start_time_of_day = 0, @active_end_time_of_day = 235959, @active_start_date = 0, @active_end_date = 0, @job_login = null, @job_password = null, @publisher_security_mode = 1
use [DatabaseA]
exec sp_addarticle @publication = N'PubAtoB', @article = N'MyReplTable', @source_owner = N'dbo', @source_object = N'MyReplTable', @type = N'logbased', @description = null, @creation_script = null, @pre_creation_cmd = N'drop', @schema_option = 0x000000000803509F, @identityrangemanagementoption = N'manual', @destination_table = N'MyReplTable', @destination_owner = N'dbo', @vertical_partition = N'false', @ins_cmd = N'CALL sp_MSins_dboMyReplTable', @del_cmd = N'CALL sp_MSdel_dboMyReplTable', @upd_cmd = N'SCALL sp_MSupd_dboMyReplTable'
GO
-----------------BEGIN: Script to be run at Publisher 'MyInstance'-----------------
use [DatabaseA]
exec sp_addsubscription @publication = N'PubAtoB', @subscriber = N'MyInstance', @destination_db = N'DatabaseB', @subscription_type = N'Push', @sync_type = N'automatic', @article = N'all', @update_mode = N'read only', @subscriber_type = 0
exec sp_addpushsubscription_agent @publication = N'PubAtoB', @subscriber = N'MyInstance', @subscriber_db = N'DatabaseB', @job_login = null, @job_password = null, @subscriber_security_mode = 1, @frequency_type = 64, @frequency_interval = 0, @frequency_relative_interval = 0, @frequency_recurrence_factor = 0, @frequency_subday = 0, @frequency_subday_interval = 0, @active_start_time_of_day = 0, @active_end_time_of_day = 235959, @active_start_date = 20060314, @active_end_date = 99991231, @enabled_for_syncmgr = N'False', @dts_package_location = N'Distributor'
GO
-----------------END: Script to be run at Publisher 'MyInstance'-----------------
use [DatabaseB]
exec sp_replicationdboption @dbname = N'DatabaseB', @optname = N'publish', @value = N'true'
GO
-- Adding the transactional publication
use [DatabaseB]
exec sp_addpublication @publication = N'PubBtoC', @description = N'Transactional publication of database ''DatabaseB'' from Publisher ''MyInstance''.', @sync_method = N'concurrent', @retention = 0, @allow_push = N'true', @allow_pull = N'true', @allow_anonymous = N'true', @enabled_for_internet = N'false', @snapshot_in_defaultfolder = N'true', @compress_snapshot = N'false', @ftp_port = 21, @ftp_login = N'anonymous', @allow_subscription_copy = N'false', @add_to_active_directory = N'false', @repl_freq = N'continuous', @status = N'active', @independent_agent = N'true', @immediate_sync = N'true', @allow_sync_tran = N'false', @autogen_sync_procs = N'false', @allow_queued_tran = N'false', @allow_dts = N'false', @replicate_ddl = 1, @allow_initialize_from_backup = N'false', @enabled_for_p2p = N'false', @enabled_for_het_sub = N'false'
GO
exec sp_addpublication_snapshot @publication = N'PubBtoC', @frequency_type = 1, @frequency_interval = 0, @frequency_relative_interval = 0, @frequency_recurrence_factor = 0, @frequency_subday = 0, @frequency_subday_interval = 0, @active_start_time_of_day = 0, @active_end_time_of_day = 235959, @active_start_date = 0, @active_end_date = 0, @job_login = null, @job_password = null, @publisher_security_mode = 1
use [DatabaseB]
exec sp_addarticle @publication = N'PubBtoC', @article = N'MyReplTable', @source_owner = N'dbo', @source_object = N'MyReplTable', @type = N'logbased', @description = null, @creation_script = null, @pre_creation_cmd = N'drop', @schema_option = 0x000000000803509F, @identityrangemanagementoption = N'manual', @destination_table = N'MyReplTable', @destination_owner = N'dbo', @vertical_partition = N'false', @ins_cmd = N'CALL sp_MSins_dboMyReplTable', @del_cmd = N'CALL sp_MSdel_dboMyReplTable', @upd_cmd = N'SCALL sp_MSupd_dboMyReplTable'
GO
-----------------BEGIN: Script to be run at Publisher 'MyInstance'-----------------
use [DatabaseB]
exec sp_addsubscription @publication = N'PubBtoC', @subscriber = N'MyInstance', @destination_db = N'DatabaseC', @subscription_type = N'Push', @sync_type = N'automatic', @article = N'all', @update_mode = N'read only', @subscriber_type = 0
exec sp_addpushsubscription_agent @publication = N'PubBtoC', @subscriber = N'MyInstance', @subscriber_db = N'DatabaseC', @job_login = null, @job_password = null, @subscriber_security_mode = 1, @frequency_type = 64, @frequency_interval = 0, @frequency_relative_interval = 0, @frequency_recurrence_factor = 0, @frequency_subday = 0, @frequency_subday_interval = 0, @active_start_time_of_day = 0, @active_end_time_of_day = 235959, @active_start_date = 20060314, @active_end_date = 99991231, @enabled_for_syncmgr = N'False', @dts_package_location = N'Distributor'
GO
-----------------END: Script to be run at Publisher 'MyInstance'-----------------
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