The tag has no usage guidance.

learn more… | top users | synonyms

22
votes
4answers
13k views

Measure the size of a PostgreSQL table row

I have a PostgreSQL table. select * is very slow whereas select id is nice and quick. I think it may be that the size of the row is very large and it's taking a while to transport, or it may be some ...
4
votes
1answer
26k views

How to Recover an InnoDB table whose files were moved around

So I have a test db server that was setup on a replication stream. Over the name an optimize came through that quickly filled up the space on the slaves datadir. Mysql dutifully was just waiting for ...
5
votes
1answer
3k views

VACUUM returning disk space to operating system

VACUUM usually does not return disk space to operating system, except in some special cases. From the docs: The standard form of VACUUM removes dead row versions in tables and indexes and marks ...
3
votes
3answers
5k views

Can I specify a different disk for a specific MySQL table?

I use my home machine as my personal database for my hobby analytics project. This machine has an SSD for the main drive where MySQL stores its data. It also has a secondary hard drive that is ...
2
votes
1answer
311 views

How big can innodb_doublewrite_file grow?

When I use the enable innodb_doublewrite_file ... How big can this file grow ? How can I calculate the optimal disk size, if it would be used only for this file?
7
votes
3answers
22k views

Query to report disk space allocation and used space

We are using 6 databases in total for an application, and we can only share 4TB of space among all 6 auto-grow databases (via SAN storage). I'd like to write a query (report) for a single database ...
11
votes
2answers
26k views

How do I shrink the innodb file ibdata1 without dumping all databases?

InnoDB stores all tables in one big file ibdata1. After dropping a big table, the file is keeping its size no matter how big the table was. How can I shrink that file without having to dump and ...
2
votes
1answer
506 views

Character varying index overhead & length limit

I have a unique constraint on a character varying column that will mostly have lengths of approximately 600 but could get to 10 million. I have read about B-Trees, but I can't determine how much disk ...
4
votes
1answer
3k views

Drop user did not reduce size of tablespace file

I have a development environment in which I frequently copy a certain schema. When I'm done with the copy, I will use OracleEM to drop that user/schema. My problem is that this does not seem to ...
3
votes
2answers
5k views

Disk space full but logical space available in database

We have a fairly big MS SQL 2008R2 database that resides on a SSD drive. The drive itself only has ~110Gb of space, and the database files are the only files on the drive. The database is in "Simple" ...
14
votes
3answers
3k views

Why might a table's data space take up 4x the size of the raw data?

I have a table with 490 M rows and 55 GB of table space, so about 167 bytes per row. The table has three columns: a VARCHAR(100), a DATETIME2(0), and a SMALLINT. The average length of the text in ...
5
votes
3answers
537 views

Get MS SQL Server to release disk space

A poorly managed database table has grown to be enormous. 48+gigs of orphan records. I am trying to clean it up and put my dangerously full hard drive back to a normal state. I will be deleting approx ...
5
votes
1answer
225 views

For alignment optimized table is bigger than original table - why?

In another question I learned that I should optimize the layout from one of my tables to save space and have better performance. I did this, but ended up with a larger table than before and ...
2
votes
2answers
434 views

space usage on sys.allocation_units and sp_spaceused

It is a known fact that the DMVs dont hold accurate information regarding number of pages and count of rows. However, when you have the stats updated, I can't see why they wouldn't. I am working on a ...
8
votes
2answers
1k views

What effect will reducing the size of a varchar column have on the database file?

We have a number of tables in our database that have VARCHAR(MAX) columns where a VARCHAR(500) (or something much smaller than max) will suffice. Naturally I want to clean these up, and get the sizes ...
4
votes
2answers
3k views

Partitioning and freeing disk space

I am running MySql innodb with innodb_file_per_table. As a daily script, I would like to create a new partition for a set of tables, as well as delete yesterday's partitions. What command would need ...
3
votes
1answer
146 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 ...
3
votes
2answers
804 views

SQL Server 2005: Full-text search space requirements

Is there a way to calculate the physical drive space required for a full-text search catalog? Space is cheap, but I'd like to know what I'm getting into. I'm looking at a table of about 200 articles ...
1
vote
2answers
12k views

Database running out of space

My database has 16MB of space left. I used to just truncate as I was taught but I found these links that advise against truncating: ...