Linked Server Insert-Select Performance

Question

Assume that I have a table on my local which is Local_Table and I have another server and another db and table, which is Remote_Table (table struct

Answer 1

The reason why it's so slow to insert into the remote table from the local table is because it inserts a row, checks that it inserted, and then inserts the next row, checks that it inserted, etc.

Don't know if you figured this out or not, but here's how I solved this problem using linked servers.

First, I have a LocalDB.dbo.Table with several columns:

IDColumn (int, PK, Auto Increment)
TextColumn (varchar(30))
IntColumn (int)

And I have a RemoteDB.dbo.Table that is almost the same:

IDColumn (int)
TextColumn (varchar(30))
IntColumn (int)

The main difference is that remote IDColumn isn't set up as as an ID column, so that I can do inserts into it.

Then I set up a trigger on remote table that happens on Delete

Create Trigger Table_Del
    On Table
    After Delete
AS
Begin
    Set NOCOUNT ON;

    Insert Into Table (IDColumn, TextColumn, IntColumn)
     Select IDColumn, TextColumn, IntColumn from MainServer.LocalDB.dbo.table L 
      Where not exists (Select * from Table R WHere L.IDColumn = R.IDColumn)

END

Then when I want to do an insert, I do it like this from the local server:

Insert Into LocalDB.dbo.Table (TextColumn, IntColumn) Values ('textvalue', 123);
Delete From RemoteServer.RemoteDB.dbo.Table Where IDColumn = 0;

--And if I want to clean the table out and make sure it has all the most up to date data:
Delete From RemoteServer.RemoteDB.dbo.Table

By triggering the remote server to pull the data from the local server and then do the insert, I was able to turn a job that took 30 minutes to insert 1258 lines into a job that took 8 seconds to do the same insert.

This does require a linked server connection on both sides, but after that's set up it works pretty good.

Update:
So in the last few years I've made some changes, and have moved away from the delete trigger as a way to sync the remote table.

Instead I have a stored procedure on the remote server that has all the steps to pull the data from the local server:

CREATE PROCEDURE [dbo].[UpdateTable]
    -- Add the parameters for the stored procedure here
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for procedure here

    --Fill Temp table
    Insert Into WebFileNamesTemp Select * From MAINSERVER.LocalDB.dbo.WebFileNames

    --Fill normal table from temp table
    Delete From WebFileNames
    Insert Into WebFileNames Select * From WebFileNamesTemp

    --empty temp table
    Delete From WebFileNamesTemp
END

And on the local server I have a scheduled job that does some processing on the local tables, and then triggers the update through the stored procedure:

EXEC sp_serveroption @server='REMOTESERVER', @optname='rpc', @optvalue='true'
EXEC sp_serveroption @server='REMOTESERVER', @optname='rpc out', @optvalue='true'
EXEC REMOTESERVER.RemoteDB.dbo.UpdateTable
EXEC sp_serveroption @server='REMOTESERVER', @optname='rpc', @optvalue='false'
EXEC sp_serveroption @server='REMOTESERVER', @optname='rpc out', @optvalue='false'