For questions about the persistent storage of database data.

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12
votes
2answers
5k views

Best way to populate a new column in a large table?

We have a 2.2 GB table in Postgres with 7,801,611 rows in it. We are adding a uuid/guid column to it and I am wondering what the best way to populate that column is (as we want to add a NOT NULL ...
6
votes
4answers
6k views

SQL Server - Separating data, log, and TempDB files on a SAN

I have a SQL Server connected to a SAN. Our new storage vendor recommends that all LUNs span the entire disk array, which is RAID5. I would normally request 3 separate LUNs (data, log, and TempDB) ...
5
votes
2answers
5k views

Splitting TempDB into multiples files equal to number of CPUs

The article SQL Server tempdb Best Practices Increase Performance suggests that I should split tempdb into a number of files equal to the number of cores. So for 4 cores you get 4 files. By ...
4
votes
2answers
1k views

Oracle extents - How can I have so many with this small size?

This is a different question than the one with the almost-identical title. Again, this is more curiosity about how Oracle Database works than anything I need to change (yes I know multiple extents ...
4
votes
2answers
2k views

How to Correctly Estimate the Average Number of I/O Operations my RAID 10 disk can offer?

The average Input/Output Operations per Second a disk can sustain is a very important factor in the tuning of MySQL / InnoDB databases, as it drives the speed with which Dirty InnoDB Buffer Pool pages ...
3
votes
1answer
162 views

Extreme storage beasts

Intro I have derived this question from my previous question Single Drive vs Multiple Drives After getting a very detailed answer from a very helpful member RolandoMySQLDBA and learning the fact that ...
3
votes
1answer
168 views

Use of integer instead of interval (of one type)

Our DB design presently has a interval column which will only be storing days (no other interval type) so it is making sense to use INT2 (smallint) instead of interval. Reference to documentation. ...
1
vote
1answer
359 views

Setting up DRBD on an active MySQL server

When it comes to setting up DRBD and MySQL, is the following possible? Set up DRBD on an active MySQL server Set up DRBD with no downtime allowed
0
votes
1answer
58 views

Proposal: MySQL blob handling revision [closed]

Why does MySQL store blobs in the direct table rather than off to the side so that if it needs to read the corresponding stuff it will read the stuff off to the side? Essentially it would create its ...
0
votes
2answers
420 views

What is the default size of text field in Postgres?

In the official documentation (http://www.postgresql.org/docs/9.1/static/datatype-character.html), it states text field is variable unlimited length. I wonder what is the default size of this field ...