For questions about the persistent storage of database data.

learn more… | top users | synonyms

19
votes
2answers
12k 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 ...
3
votes
1answer
362 views

How do completely empty columns in a large table affect performance?

I have 400 million rows in a Postgres db, and the table has 18 columns: id serial NOT NULL, a integer, b integer, c integer, d smallint, e timestamp without time zone, f smallint, g timestamp without ...
7
votes
4answers
8k 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) ...
7
votes
2answers
7k 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
2k 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 ...
1
vote
1answer
80 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 ...
4
votes
2answers
3k 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
166 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 ...
4
votes
1answer
368 views

Storing phone number in E.164

TLDR; If I store a phone number in MySQL(or any DB with equivalent constraints), would the correct format be E.164 values into a VARCHAR(32) field? Have been reading up on format/storage of ...
3
votes
1answer
365 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
410 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
0answers
27 views

MySQL Storage Engine and Memory

I recently found out that, the databases does not have standard architecture(data model), some of them are, No relationship between tables(entities). No indexes defined. Only integer and varchar ...
0
votes
2answers
56 views

MySQL Backup Strategy

We are running the backup from the replication server and it is working good, since we are not facing any other issues, some information for better understanding our strategy: Backup Type: Full ...
0
votes
2answers
961 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 ...