Tips and Techniques: Database Limits

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Several years ago, an IBMer was on a mission to raise or eliminate many of the upper limits in OS/400--for example, to increase the maximum length of an index for a file from 120 bytes to the 2000 bytes we have today.

Recently, while teaching at a client's office, I was asked about database limits. What's the maximum width of a database record? What is the maximum number of records in a file? And so forth. So I put together a little table of maximums for database. The original source for these figures is, like everything, in the various IBM manuals as well as the InfoCenter at IBM.

Database Item
Limit
Fields in a record format
8,000
Bytes in a record format
32,766
Bytes in a database file
1 TB
Fields that make up an index entry
120
Bytes in an index entry
2,000
Bytes in an entire index
1 TB
Records in a file
4 GB
Indexes over a physical file member
4000
Members that may be joined (using DDS)
32
Members that may be joined (using SQL)
256
Records locked for a commitment control transaction
About 500,000,000
Triggers on a file
300
Members in a file
32,767
Files that may be used at one time
500,000
Length of a character field in database
32,765
8-byte INT (20I0 in RPG)
From:
-922,337,2036,854,775,808
To: +922,337,2036,854,775,807
4-byte INT (10I0 in RPG)
From: -2,147,483,648
To: +2,147,483,647
2-byte INT (5I0 in RPG)
From: -32,768
To: +32,767
1-byte INT (3I0 in RPG)
From: -256 to +255
Length of a packed/zoned decimal value
V5R2: 31
V5R3: 63
Objects in a library
360,000
Files that can be open at one time by the file server
16,776,960
Bytes for a Domino database
256 GB
Records in a version of the history log
65,535
Input fields on a display file at one time
256

Bob Cozzi has been programming in RPG since 1978. Since then, he has written many articles and several books, including The Modern RPG Language--the most widely used RPG reference manual in the world. Bob is also a very popular speaker at industry events such as RPG World and is the author of his own Web site and of the RPG ToolKit, an add-on library for RPG IV programmers.

BOB COZZI

Bob Cozzi is a programmer/consultant, writer/author, and software developer. His popular RPG xTools add-on subprocedure library for RPG IV is fast becoming a standard with RPG developers. His book The Modern RPG Language has been the most widely used RPG programming book for more than a decade. He, along with others, speaks at and produces the highly popular RPG World conference for RPG programmers.


MC Press books written by Robert Cozzi available now on the MC Press Bookstore.

RPG TnT RPG TnT
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The Modern RPG IV Language The Modern RPG IV Language
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