fering build need temporary disk space, up to
   the size of the resulting index. Buffering can also influence the quality
   of the resulting index, in both positive and negative directions. That
   influence depends on various factors, like the distribution of the input
   data and the operator class implementation.
  </P
><P
>   By default, a GiST index build switches to the buffering method when the
   index size reaches <A
HREF="runtime-config-query.html#GUC-EFFECTIVE-CACHE-SIZE"
>effective_cache_size<