The <keycompress> option defaults to index compression.
The following <keycompress> suboptions specify which compression type to use:
The new index compression does not support the <leading> compression type. The old index compression can be used by disabling <keycompress vlennod> (enabled by default), which allows the <leading> and <padding> to be specified. The new <rle> option cannot be specified when the <keycompress vlennod> attribute is disabled. The <rle> and <padding> sub-options are mutually exclusive unlike the old index compression where it was possible to combine <leading> and <padding>.
The following examples turn on the new index compression:
<keycompress/>
<keycompress>1</keycompress>
<keycompress><rle/></keycompress>
<keycompression><padding>1</padding></keycompression>
The following examples enabled the old index compression:
<keycompress vlennod="no"/>
<keycompress vlennod="0">1</keycompress>
<keycompress vlennod="false"><leading>1</leading></keycompress>
<keycompression vlennod="n"><leading/><padding/></keycompression>