When analyzing Merge Performance use standard DBA tools to analyze key Merge query performance.
SQL SERVER MERGE FULL
Subscribers can be full SQL Server or SQL Compact Edition subscribers. Subscribers can synchronize over direct LAN/VPN SQL SQL or over WAN network or SQL IIS SQL (called Web Sync).
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This allows the database to be restored with little or no loss of user data. Unlike Transactional Replication it does not contain data from user tables. A conflict is caused when same row/column is changed on 2 different SQL Servers.ĭistribution Database is only used to track Merge Replication historical data. Merge processes includes logic to determine which SQL “win” in the event of a conflict. Most important is msmerge_contents which contains one row for each modified record. This information is stored in systems tables. Merge uses Replication created triggers on user table to flag what data needs to be moved to which subscribers. Optimizing Parameterized Filter Performance with Precomputed Partitions This SQL 2000 option is still supported for backward compatibility. The SQL 2000 method instead forces each subscriber to execute these same Filters against ALL the Publisher data in order to find that subscriber rows. All the subscriber needs to do is query for its already preallocated data.
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This offloads the Filter logic to the updates on Publisher. JOIN filters are queries defined using JOIN between two or more tables such as SELECT * FROM OrderHeader JOIN OrderDetails.īy default Merge will use these filters when data is INS/UPD/DEL to predetermine which subscriber will get the data. SUBSET filters are queries defined with SELECT WHERE clause used to limit rows for a subscriber such as SELECT * from Customers where SalesPerson = Suser_Sname().
SQL SERVER MERGE DRIVER
For example, a route driver with a Pocket PC only needs to see stop on their route and not stops for all routes. Filters are used to determine which subscriber gets which data. Not all subscribers need to get the same data.
SQL SERVER MERGE DOWNLOAD
When Synchronization is complete and all changes have been upload to central Publisher and download to the Subscriber the servers are considered “in synch”. SQL Server Merge.exe will “blend” data between 2 different SQL Servers. The Subscribers can have a complete copy of a subset of the Publisher data. Merge is design with a central Publisher containing a master copy of the data and remote Subscribers with a copy of the Publisher data.
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I do not know if this issue has ever been addressed in later editions. VALUES (source.webmeterID, source.DateTime, source.kWh)īecause this has become a bit more popular, I feel like I should expand this answer a bit with some caveats to be aware of.įirst, there are several blogs which report concurrency issues with the MERGE statement in older versions of SQL Server. If you also want to delete records in the target that aren't in the source: MERGE INTO dbo.energydata WITH (HOLDLOCK) AS target
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VALUES (source.webmeterID, source.DateTime, source.kWh) Assuming you want an actual SQL Server MERGE statement: MERGE INTO dbo.energydata WITH (HOLDLOCK) AS target