   Hash-based operations are generally more sensitive to memory
        availability than equivalent sort-based operations.  The
        memory limit for a hash table is computed by multiplying
        <code class="varname">work_mem</code> by
        <code class="varname">hash_mem_multiplier</code>.  This makes it
        possible for hash-based operations to use an amount of memory
        that exceeds the usual <code class="varname">work_mem</code> base
        amount.
       </p></dd><dt id="GUC-HASH-MEM