How to move data from big table

Question

There is a big table (5-6 million records). I have to move 90% of old records to other database(table). Solution?

Answer 1

Couple of additions to Rolando's suggestion.

If you're clearing out the old table, as well as populating new you could use the OUTPUT clause. Be mindful of the potential for log growth, consider a loop/batch approach if this may be a problem.

DELETE
    OldDatabase.dbo.MyTable
OUTPUT
    DELETED.col1
    , DELETED.col2
    , DELETED.col3
INTO
    NewDatabase.dbo.MyTable

BCP is a handy alternative to be aware of. Note this is using SQLCMD syntax.

:setvar SourceServer OldServer
:setvar SourceDatabase OldDatabase
:setvar DestinationServer NewServer
:setvar DestinationDatabase NewDatabase
:setvar BCPFilePath "C:\"

!!bcp "$(SourceDatabase).dbo.MyTable" FORMAT nul -S "$(SourceServer)" -T -n -q -f "$(BCPFilePath)MyTable.fmt"
!!bcp "SELECT * FROM $(SourceDatabase).dbo.MyTable WHERE col1=x AND col2=y" queryout "$(BCPFilePath)MyTable.dat" -S "$(SourceServer)" -T -q -f "$(BCPFilePath)MyTable.fmt" -> "$(BCPFilePath)MyTable.txt"
!!bcp "$(DestinationDatabase).dbo.MyTable" in $(BCPFilePath)MyTable.dat -S $(DestinationServer) -T -E -q -b 2500 -h "TABLOCK" -f $(BCPFilePath)MyTable.fmt

Answer 2

For SQL-Server the real problem is avoiding the logging of the deleted rows.

My proposal is Set up a second database in simple recovery mode. Copy the the hole table with

Select * into SEM..Copy from Original

Truncate Original

Insert into Original Select * from SEM..Copy

If target Server Is SQL-Server of same revision you can move the data by backup and restore.

In other cases take some bulkcopy option.

EDIT:

Although it is time to learn about partioned tables, but that seems to be an option only for Enterprise Edition.

Answer 3

Disclaimer : I am not a SQL Server guy.

The following pseudo SQL should do it for you in principle

• create tableB like tableA
• INSERT INTO tableB SELECT * FROM tableA WHERE (whatever makes up the 10% to stay)
• DELETE FROM tableA WHERE (whatever makes up the 10% to stay)
• RENAME tableA to tableC
• RENAME tableB to tableA
• DROP TABLE tableC (Optional)

I hope this helps and I hope there are no foreign key constraints involved !!!

Answer 4

If the TableA is really big, you can use bulk-operations and bcp utility

1. export the data from TableA using bcp utility into file
2. Create the TableB
3. Import the data using bulk insert or openrowset (bulk...)
4. delete old data from TableA
5. rename the tables, if needed

see the About Bulk Import and Bulk Export Operations article.