Reddit's database has only two tables

Steve Huffman talks about Reddit’s approach to data storage in a High Scalability post from 2010. I was surprised to learn that they only have two tables in their database.

Lesson: Don’t worry about the schema.
[Reddit] used to spend a lot of time worrying about the database, keeping everthing nice and normalized. You shouldn’t have to worry about the database. Schema updates are very slow when you get bigger. Adding a column to 10 million rows takes locks and doesn’t work. They used replication for backup and for scaling. Schema updates and maintaining replication is a pain. They would have to restart replication and could go a day without backups. Deployments are a pain because you have to orchestrate how new software and new database upgrades happen together.
Instead, they keep a Thing Table and a Data Table. Everything in Reddit is a Thing: users, links, comments, subreddits, awards, etc. Things keep common attribute like up/down votes, a type, and creation date. The Data table has three columns: thing id, key, value. There’s a row for every attribute. There’s a row for title, url, author, spam votes, etc. When they add new features they didn’t have to worry about the database anymore. They didn’t have to add new tables for new things or worry about upgrades. Easier for development, deployment, maintenance.
The price is you can’t use cool relational features. There are no joins in the database and you must manually enforce consistency. No joins means it’s really easy to distribute data to different machines. You don’t have to worry about foreign keys are doing joins or how to split the data up. Worked out really well. Worries of using a relational database are a thing of the past.

This fits with a piece I read the other day about how MongoDB has high adoption for small projects because it lets you just start storing things, without worrying about what the schema or indexes need to be. Reddit’s approach lets them easily add more data to existing objects, without the pain of schema updates or database pivots.

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What is sfsutl, How Should SFSUTL.EXE be Used?

sfsutl.exe can be found in Siebsrvr\bin directory, in siebel versions 6 and older SFSUTL.EXE used to delte the orphan and old versions of attachments.

in Siebel 7 and Siebel 8 a new utility called SFSCLEANUP has been introduced.
sfsutl can be used to verify the integrity between database records and files in the Siebel File System, or to remove files from the Siebel File System that no longer have a corresponding database record.
SFSUTL works in two modes:

1. verify or report

2.move or delete.
1.Verify or Report Mode:
To use the utility in verify or report mode, enter a command string similar to the following:
sfsutl /u sadmin /p sadmin /c siebsrvr_siebel /d dbo /f e:\siebfile /x c:\sfsutl_output.txt
The output from this command could be easily imported into Microsoft utilities like Excel or Access for sorting and manipulation. See below for sample output from this command. There are three key statuses to note:
•Keeping - The file corresponds to a database record.
•Discard - The file does not correspond to a database record, and would be moved or deleted if sfsutl were run in that mode.
•Missing - An expected file does not exist for a database record.
2.Move or Delete Mode:
To use the utility in move or delete mode:
1.Create a separate or new folder (this will be used by sfsutl when moving the discarded files). It is recommended that users do not create this new folder as a subfolder of the existing Siebel File System. For example, if the Siebel File System is in e:\siebfile then create the new folder as e:\siebfilediscards.
2.Enter a command string similar to the following:
sfsutl /u sadmin /p sadmin /c siebsrvr_siebel /d dbo /f e:\siebfile /m e:\siebfilediscards /x c:\sfsutl_output.txt