A SQL statement typically used to `UPDATE` records when they exist and `INSERT` them when they do not.

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Can I optimize this MERGE statement?

I am attempting a single column merge between two tables. The first table (VisitorSession) has 40,000,000 rows. The second (ShoppingCart) has 9,000,000 rows. In my development environment, the query ...
2
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1answer
179 views

Help with best practice of merging databases

Bad news, our website server (Windows 2003) crashed because of dead RAID controller. Luckily few hours later our backup server was up and website was live again. Hopefully tomorrow our original ...
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0answers
52 views

Transfer tables from multiple servers into one single server [duplicate]

I have to migrate similar tables present in multiple different servers (30+) into our new server using SSIS package. What would be the right approach towards this? I was successfully able to transfer ...
1
vote
1answer
388 views

Merge Statement + Replication difference for SQL Server 2012

We have a SSIS package that will pull from a source database and run a merge statement to put the data into a "Master" database. (Eventually the "Master" database will be the source of truth, but we ...
1
vote
1answer
221 views

Equivalent of MRG_MYISAM in databases other than MySQL? [closed]

Does anyone know if other database have something equivalent to MRG_MYISAM (aka the MERGE table type/storage engine)? I know about fragmenting, but this is not quite the same AFAIK. We're using ...
1
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2answers
703 views

getting error when i use merge statement

I am using sql 2008 r2. when i use merge statement i am gettig error when i execute following code: merge products as trgt using updatedproducts as src on (trgt.productid = src.productid) ...
31
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1answer
20k views

MERGE a subset of the target table

I am trying to use a MERGE statement to insert or delete rows from a table, but I only want to act on a subset of those rows. The documentation for MERGE has a pretty strongly worded warning: It ...
1
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1answer
210 views

Is there a way to write intelligent queries against a merge table in MySQL that represents a bunch of tables partitioned by date?

I have a set of MySQL tables that are partitioned by date, with a merge table representing all of them. For the query I am writing, the results are joined by date, so rows in table A_2012-12-05 will ...
5
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1answer
2k views

MERGE with OUTPUT doesn't seem to be doing the right thing

I'm adding a foreign key to a table, and removing any rows that violate the FK, copying them into a ModifiedTable_invalid table. As part of the script, I've got the following MERGE command: MERGE ...
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2answers
2k views

Merge two records in the same table, keeping foreign key relationships intact for both

I have a table, called SITES, that has three columns, lets say it looks like this: ID Name Path 1 Google http://www.google.com/ 2 Microsoft http://www.microsoft.com/ I also have ...
2
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1answer
909 views

oracle merge operation hangs (or loops); query tuner claims it's a cartesian product operation

I have a Merge query (open to better suggestions) that seems to cause the server to hang. (I'm not sure what it's doing, but it pegs the CPU and never completes) When I run it through the query ...
3
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0answers
125 views

Once in a while synchronization of the independently updated mysql databases problem

I have a production database and a test database running on MySQL with MyISAM and InnoDB tables, which are updated independently. The Production database is updated by system and sometimes by a user. ...
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3answers
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SQL Server 2008 merge statement deadlocking itself

I have the following procedure (SQL Server 2008r2): create procedure usp_SaveCompanyUserData @companyId bigint, @userId bigint, @dataTable tt_CoUserdata readonly as begin set ...
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2answers
1k views

Merge replication fails on executing query

My merge replication was working fine this morning. Since an hour or 2 ago, my synchronisation status windows keeps showing this message: Thread id 3108 will wait for 15 second(s) before retrying the ...
5
votes
2answers
614 views

How to use merge hints to isolate complex queries in SQL Server

I can understand that if I join individual queries that are "individually fast" the combination may become slow because the default execution plan may be non-optimal. However when I know the number ...
6
votes
1answer
4k views

What are my locking options for a Merge statement?

I have a stored procedure that performs a MERGE statement. It seems like it locks the whole table by default when performing the merge. I'm calling this stored procedure inside of a transaction ...
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0answers
199 views

What overhead is there if I MERGE row by row?

I have a target table of about 2000 rows and I want to be able to MERGE (with HOLDLOCK) about 5-10 rows at a time into the target table. The target table doesn't get used heavily, with only 1-2 users ...
0
votes
1answer
136 views

Re-subscribing to a merge publication after edits made offline

Hypothetical Question - To help scenario planning. Let's say I have a 2008 R2 Merge Publication with 5 active subscribers. The publication is deleted and all subscriptions are removed. A week or so ...
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2answers
4k views

Oracle's Merge v. Select->Update/Insert

What is the faster statement? A MERGE or Select->Update/Insert depending on if it returns a value? I'm trying to optimize a database, but I haven't found any speed tests comparing the two. I found ...