Home Forums SQL Server 2012 SQL Server 2012 - T-SQL How to quickly update/insert 3M records in a large table? RE: How to quickly update/insert 3M records in a large table?

  • March 30, 2015 at 11:20 am

    #1787439

    Jeff Moden (3/30/2015)

    Jason-299789 (3/30/2015)

    I would also suggest that the key on both the destination table is clustered it should make the process significantly faster. so something like.

    "It Depends". Unless the key is ever increasing, Inserts could suffer dramatically due to page splits no matter how they are accomplished.

    And I'm not so sure that MERGE will provide anything substantial in the area of performance. To be honest, I'm also not sure that it won't, so it's worth a try even if my hypothesis is that it won't. I don't use MERGE in SQL Server because there have been way too many reported problems with it and I can tolerate doing "l' fashioned", yet effective "upserts" until that the reported problems seriously decline.

    This looks like being close to the ideal case for a MERGE, given that few precautions are in place such as the source set must be distinct, no conflicting match conditions etc.. If one knows and observes those prerequisites, the MERGE works like a charm.

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