This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.
What this hour is for
The size estimator multiplies the row count you type by the width you type and divides into megabytes. It says indexes often add 20 to 50 percent. The row-size calculator is the width you add up from the columns. Both are arithmetic on numbers you type. They do not read a database.
Label the result as an estimate. Do not order storage from it. Measure a copy when the number matters.
192.0.2.10, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. A sample password is replaced. It is not a password you keep.
The change you can finish
Apply nothing while you are writing the note. When the lab window opens, it is one change on the database named in the ticket. Read the draft, then the database, then decide.
Rollback is the backup, the file, or the snapshot you saved first. You do not invent a rollback after the only copy is gone.
- Type rows and width.
- Read the megabytes.
- Add the index range in the note.
- Label it an estimate.
- Stop.
Mistakes that outlive the statement
How to Estimate Database Size goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- The estimate treated as a measured size.
- Disks ordered from the page.
- A width you did not add up.
Decisions to write down
One decision for How to Estimate Database Size: Rows and width are written. The number is labeled an estimate. Indexes are a range. And the database is yours.
Checks before you call it done
Confirm this before you call the change done: Rows are written. Width is written. The megabytes are written. The index range is written. And it is an estimate. If one of those fails, stop.
Before you leave the database
How to Estimate Database Size ends when the database in the prompt is the database in the ticket. If it is not, you are on the wrong database. Stop.
The draft stays a draft until a person has read the names in it. A generator does not log into the database. You delete a line that names a host, a database, or an account you did not write down.
192.0.2.10, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. example.com is a documentation name. They belong in the note. They are not values you leave on a database because a draft included them.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, or a token you save in the ticket or in git. A sample password in a draft is replaced. It is not a password you keep.
One change is the window. If two things move and the result is wrong, you will not know which one did it.
If the same step fails twice, stop for the day. Restore the copy you took first.
A second person reads the database name and the change aloud. If they cannot find them in the ticket, the note is not done.
This page is a planning guide. It is not a vendor manual, not an official standard, and not permission to touch a database you do not administer. You do not disable authentication, a firewall, or TLS to make a check pass.
Tools for this guide
These tools run in the browser on this site. They do not log into your machines.
Related pillar guides
More in this cluster
The pillar for this page, and the next published pages filed with it.