What is the maximum permissable length for the key value when writing to and
reading from a indexed RMS file?
(9809) Longest RMS indexed file key string?
Re: (9809) Longest RMS indexed file key string?
The strict answer to the question is 255 byte.
That written, a key that long is likely to have serious performance
implications. Accordingly, the OpenVMS Wizard urges you to review
RMS concepts in the Guide to OpenVMS File Applications manual.
If, after reading that material, you are still convinced you need a
key as large as possible, then be sure to consider Key Compression
and Index Compression, as well as relatively large bucket sizes.
References:
HELP/MESSAGE/FACILITY=RMS "key size"
The RMS Reference Manual, under the discussion of XABKEY.
When the data type of the key is string, the total size (sum of
all sizes) of the key must be less than 256 bytes.
Guide to OpenVMS File applications, and most notably the performance
considerations and the discussion of idexed files; see chapters two
and three in the current manual.
That written, a key that long is likely to have serious performance
implications. Accordingly, the OpenVMS Wizard urges you to review
RMS concepts in the Guide to OpenVMS File Applications manual.
If, after reading that material, you are still convinced you need a
key as large as possible, then be sure to consider Key Compression
and Index Compression, as well as relatively large bucket sizes.
References:
HELP/MESSAGE/FACILITY=RMS "key size"
The RMS Reference Manual, under the discussion of XABKEY.
When the data type of the key is string, the total size (sum of
all sizes) of the key must be less than 256 bytes.
Guide to OpenVMS File applications, and most notably the performance
considerations and the discussion of idexed files; see chapters two
and three in the current manual.