Configurable substring index lengths (ITS#2661)

[gwingerde@home.nl]

Full_Name: Gertjan van Wingerde
Version: 2.1.22
OS: Linux
URL: ftp://ftp.openldap.org/incoming/gwingerde-openldap-2.1.22-config_substr_length.diff
Submission from: (NULL) (212.120.112.51)


The patch indicated below makes the minimum and maximum lengths for substring
indexing
configurable via slapd.conf, as well as the step size taken while creating the
substring indexes.

The use-case for this patch is an application which is performing
wildcard-searches on
telephone-number prefixes. For this particular application the telephone-numbers
were
stored in international format, making the first 4 characters of all telephone
numbers equal.
Hence, in this setup the standard minimum length of 2 and maximum length of 4 of
OpenLDAP
was not sufficient for efficient substring indexing (the LDAP directory contains
hundreds of
thousands of entries).

As longer substring indexes can have a profound impact on write performance it
is chosen
to make the minimum length, the maximum length and the step size for substring
indexes
configurable, to give administrators full control over the behaviour of their
LDAP directories.

The defaults for the newly introduced configuration items are identical to the
current hardcoded
values.

The uploaded patch contains both changes to the software, as updates for the
slapd.conf
manual page.