By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
426,165 Members | 1,901 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 426,165 IT Pros & Developers. It's quick & easy.

Copy 60GB table?

P: n/a
I'm trying to copy all 440 million rows from one table in my SQL Server
2005 db to another table with a different clustering scheme. After a
few test inserts that were successful (up to a million rows in 20
seconds with no problem), I crossed my fingers and went whole-hog with
the naive "insert into dest_table (column1, column2, ...) select
column1, column2, ... from source_table" but of course it ran out of
space in *both* the db log file (at about 130 GB) and the tempdb log
file (at about 54GB) and rolled it back, wrapping up 10 hours after I
kicked it off.

I think it would work if I could insert in batches and/or disable
logging, like with a bulk insert, so I tried exporting the source table
to a flat file in the hopes of bulk-importing it back into the
destination table, but the export just halted for no reason after 176
million rows, using all the CPU and not doing anything at all, just
sitting there. (The fact that this operation not only failed, but
brought down the whole server - any operation on any database in the
instance timed out, no clients could connect, the whole deal - I find
very disappointing for what MS claimed was a scalable, robust product
that could rival Oracle.)

What I'm wondering is, does anyone know of a way to copy a table that
is apparently just too large for SQL Server 2005 to handle?

Thanks,
Seth

May 10 '06 #1
Share this Question
Share on Google+
6 Replies


P: n/a
sql_server_user (ka*******@gmail.com) writes:
I'm trying to copy all 440 million rows from one table in my SQL Server
2005 db to another table with a different clustering scheme. After a
few test inserts that were successful (up to a million rows in 20
seconds with no problem), I crossed my fingers and went whole-hog with
the naive "insert into dest_table (column1, column2, ...) select
column1, column2, ... from source_table" but of course it ran out of
space in *both* the db log file (at about 130 GB) and the tempdb log
file (at about 54GB) and rolled it back, wrapping up 10 hours after I
kicked it off.


That operation is definitely not a walk in a park.

I think I would attempt this strategy:

1) Set recovery for the database to simple recovery.
2) Create the clustered index on the target table with a relatively low
fill factor, say 30%. (Of course, no NC indexes would be in place.)
3) Insert batchwise from the old table, where batches are defined by
intervals of the clustered index of the source table. For batchsize,
I would use 100000 to 500000 rows, depending on wide the table is.
4) I would make the control loop so that it is easy to stop it. For
instance on each iteration read from a control table. Possibly also
a table the defines the batches, so you can keep track of what has
been copied. But the table should not be joined with the INSERT;
read interval into variales.
5) Occassionally stop the process and monitor fragmentation in
target table. It should first decrease, as holes are filled in,
but then it will increase again. (But you will probably see this
from the fact that the time for iteration increases.)
6) Once everything is done, switch to full recovery and backup the
database.

My thinking here is that creating the clustered index on this monster
is going require a lot of log and tempdb - you can guess what happens.
So let's have the clustered index in place from the start, even if
that will take longer time.

--
Erland Sommarskog, SQL Server MVP, es****@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pro...ads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinf...ons/books.mspx
May 10 '06 #2

P: n/a
Thanks, Erland - I'm gonna have to pay you a consulting fee soon.

The recovery model is set to simple, there are no nonclustered indexes
on the table, and I agree that clustering on insert is the way to go,
since I think trying to recluster the new table with all the data in it
would just blow up the logs and tempdb like my initial insert attempt.
I like the idea of the batched insert with the low fill factor
clustered index, however, I ran a bunch of tests and the amount of log
and tempdb space required seems to be a function of the size of the
destination table, not the number of rows in the batch: I would insert
a batch (10 million rows), shrink the log and tempdb, insert another
batch, and so on, and every time, the log and tempdb would require more
space, roughly linearly as my very approximate data below indicate:

after 1st batch: log = 1GB, tempdb = 2GB
after shrinking and 2nd batch: log = 2GB, tempdb = 4GB
after shrinking and 3rd batch: log = 3 GB, tempdb = 6GB

So I'm worried about the batch approach for the full insert.

I'm currently trying an SSIS copy from one table to the other, and
since it's doing a bulk insert it doesn't seem to be touching the db
log. However, tempdb is getting pretty fat, 12GB and going strong, but
I've cleared a lot of room for it this time - it has about 179GB to go,
so hopefully that will be enough. If this doesn't work I'll definitely
try your batched insert suggestion.

Thanks again,
Seth

Erland Sommarskog wrote:
sql_server_user (ka*******@gmail.com) writes:
I'm trying to copy all 440 million rows from one table in my SQL Server
2005 db to another table with a different clustering scheme. After a
few test inserts that were successful (up to a million rows in 20
seconds with no problem), I crossed my fingers and went whole-hog with
the naive "insert into dest_table (column1, column2, ...) select
column1, column2, ... from source_table" but of course it ran out of
space in *both* the db log file (at about 130 GB) and the tempdb log
file (at about 54GB) and rolled it back, wrapping up 10 hours after I
kicked it off.


That operation is definitely not a walk in a park.

I think I would attempt this strategy:

1) Set recovery for the database to simple recovery.
2) Create the clustered index on the target table with a relatively low
fill factor, say 30%. (Of course, no NC indexes would be in place.)
3) Insert batchwise from the old table, where batches are defined by
intervals of the clustered index of the source table. For batchsize,
I would use 100000 to 500000 rows, depending on wide the table is.
4) I would make the control loop so that it is easy to stop it. For
instance on each iteration read from a control table. Possibly also
a table the defines the batches, so you can keep track of what has
been copied. But the table should not be joined with the INSERT;
read interval into variales.
5) Occassionally stop the process and monitor fragmentation in
target table. It should first decrease, as holes are filled in,
but then it will increase again. (But you will probably see this
from the fact that the time for iteration increases.)
6) Once everything is done, switch to full recovery and backup the
database.

My thinking here is that creating the clustered index on this monster
is going require a lot of log and tempdb - you can guess what happens.
So let's have the clustered index in place from the start, even if
that will take longer time.

--
Erland Sommarskog, SQL Server MVP, es****@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pro...ads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinf...ons/books.mspx


May 10 '06 #3

P: n/a

"sql_server_user" <ka*******@gmail.com> wrote in message
news:11**********************@u72g2000cwu.googlegr oups.com...
Thanks, Erland - I'm gonna have to pay you a consulting fee soon.

BTW, might be worth looking at using BCP to dump it out and then insert it
into the new table.

Then build your indices.

The recovery model is set to simple, there are no nonclustered indexes
on the table, and I agree that clustering on insert is the way to go,
since I think trying to recluster the new table with all the data in it
would just blow up the logs and tempdb like my initial insert attempt.
I like the idea of the batched insert with the low fill factor
clustered index, however, I ran a bunch of tests and the amount of log
and tempdb space required seems to be a function of the size of the
destination table, not the number of rows in the batch: I would insert
a batch (10 million rows), shrink the log and tempdb, insert another
batch, and so on, and every time, the log and tempdb would require more
space, roughly linearly as my very approximate data below indicate:

after 1st batch: log = 1GB, tempdb = 2GB
after shrinking and 2nd batch: log = 2GB, tempdb = 4GB
after shrinking and 3rd batch: log = 3 GB, tempdb = 6GB

So I'm worried about the batch approach for the full insert.

I'm currently trying an SSIS copy from one table to the other, and
since it's doing a bulk insert it doesn't seem to be touching the db
log. However, tempdb is getting pretty fat, 12GB and going strong, but
I've cleared a lot of room for it this time - it has about 179GB to go,
so hopefully that will be enough. If this doesn't work I'll definitely
try your batched insert suggestion.

Thanks again,
Seth

Erland Sommarskog wrote:
sql_server_user (ka*******@gmail.com) writes:
I'm trying to copy all 440 million rows from one table in my SQL Server 2005 db to another table with a different clustering scheme. After a
few test inserts that were successful (up to a million rows in 20
seconds with no problem), I crossed my fingers and went whole-hog with
the naive "insert into dest_table (column1, column2, ...) select
column1, column2, ... from source_table" but of course it ran out of
space in *both* the db log file (at about 130 GB) and the tempdb log
file (at about 54GB) and rolled it back, wrapping up 10 hours after I
kicked it off.


That operation is definitely not a walk in a park.

I think I would attempt this strategy:

1) Set recovery for the database to simple recovery.
2) Create the clustered index on the target table with a relatively low
fill factor, say 30%. (Of course, no NC indexes would be in place.)
3) Insert batchwise from the old table, where batches are defined by
intervals of the clustered index of the source table. For batchsize,
I would use 100000 to 500000 rows, depending on wide the table is.
4) I would make the control loop so that it is easy to stop it. For
instance on each iteration read from a control table. Possibly also
a table the defines the batches, so you can keep track of what has
been copied. But the table should not be joined with the INSERT;
read interval into variales.
5) Occassionally stop the process and monitor fragmentation in
target table. It should first decrease, as holes are filled in,
but then it will increase again. (But you will probably see this
from the fact that the time for iteration increases.)
6) Once everything is done, switch to full recovery and backup the
database.

My thinking here is that creating the clustered index on this monster
is going require a lot of log and tempdb - you can guess what happens.
So let's have the clustered index in place from the start, even if
that will take longer time.

--
Erland Sommarskog, SQL Server MVP, es****@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pro...ads/books.mspx Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinf...ons/books.mspx

May 11 '06 #4

P: n/a
> 2) Create the clustered index on the target table with a relatively low
fill factor, say 30%. (Of course, no NC indexes would be in place.)
As the table is empty there is no point putting on the fillfactor because
its not enforced for new pages.

Only good for creating indexes on existing data.

I agree though - clustered index should be in place before you start.

--
Tony Rogerson
SQL Server MVP
http://sqlserverfaq.com - free video tutorials
"Erland Sommarskog" <es****@sommarskog.se> wrote in message
news:Xn**********************@127.0.0.1... sql_server_user (ka*******@gmail.com) writes:
I'm trying to copy all 440 million rows from one table in my SQL Server
2005 db to another table with a different clustering scheme. After a
few test inserts that were successful (up to a million rows in 20
seconds with no problem), I crossed my fingers and went whole-hog with
the naive "insert into dest_table (column1, column2, ...) select
column1, column2, ... from source_table" but of course it ran out of
space in *both* the db log file (at about 130 GB) and the tempdb log
file (at about 54GB) and rolled it back, wrapping up 10 hours after I
kicked it off.


That operation is definitely not a walk in a park.

I think I would attempt this strategy:

1) Set recovery for the database to simple recovery.
2) Create the clustered index on the target table with a relatively low
fill factor, say 30%. (Of course, no NC indexes would be in place.)
3) Insert batchwise from the old table, where batches are defined by
intervals of the clustered index of the source table. For batchsize,
I would use 100000 to 500000 rows, depending on wide the table is.
4) I would make the control loop so that it is easy to stop it. For
instance on each iteration read from a control table. Possibly also
a table the defines the batches, so you can keep track of what has
been copied. But the table should not be joined with the INSERT;
read interval into variales.
5) Occassionally stop the process and monitor fragmentation in
target table. It should first decrease, as holes are filled in,
but then it will increase again. (But you will probably see this
from the fact that the time for iteration increases.)
6) Once everything is done, switch to full recovery and backup the
database.

My thinking here is that creating the clustered index on this monster
is going require a lot of log and tempdb - you can guess what happens.
So let's have the clustered index in place from the start, even if
that will take longer time.

--
Erland Sommarskog, SQL Server MVP, es****@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pro...ads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinf...ons/books.mspx

May 11 '06 #5

P: n/a
Tony Rogerson (to**********@sqlserverfaq.com) writes:
2) Create the clustered index on the target table with a relatively low
fill factor, say 30%. (Of course, no NC indexes would be in place.)


As the table is empty there is no point putting on the fillfactor because
its not enforced for new pages.

Only good for creating indexes on existing data.

I agree though - clustered index should be in place before you start.


Eh, I guess that I will have to stick with my general lame excuse that
the hour was late.

However, it could maybe be idea to reindex every now and then with a low
fill-factor.

--
Erland Sommarskog, SQL Server MVP, es****@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/pro...ads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinf...ons/books.mspx
May 11 '06 #6

P: n/a
SSIS worked. It looks like it just put the *entire* table in tempdb -
to sort it into the new clustering order, I guess. The key was
eliminating logging with the bulk insert. Thanks for the help,
everybody.

May 11 '06 #7

This discussion thread is closed

Replies have been disabled for this discussion.