Grab some low-hanging fruit in the new hash index build code.

oprofile shows that a nontrivial amount of time is being spent in
repeated calls to index_getprocinfo, which really only needs to be
called once.  So do that, and inline _hash_datum2hashkey to make it
work.

diff --git a/src/backend/utils/sort/tuplesort.c b/src/backend/utils/sort/tuplesort.c
index 04782c8e6587a1ba7fd723f45ef9bea43144dfdf..0edd350a8f8c3bd7d0368816acb90a4c9cb1c816 100644 (file)
--- a/src/backend/utils/sort/tuplesort.c
+++ b/src/backend/utils/sort/tuplesort.c
@@ -91,7 +91,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/sort/tuplesort.c,v 1.82 2008/03/16 23:15:08 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/sort/tuplesort.c,v 1.83 2008/03/17 03:45:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -100,6 +100,7 @@
 
 #include <limits.h>
 
+#include "access/genam.h"
 #include "access/hash.h"
 #include "access/heapam.h"
 #include "access/nbtree.h"
@@ -346,6 +347,7 @@ struct Tuplesortstate
        bool            enforceUnique;  /* complain if we find duplicate tuples */
 
        /* These are specific to the index_hash subcase: */
+       FmgrInfo   *hash_proc;          /* call info for the hash function */
        uint32          hash_mask;              /* mask for sortable part of hash code */
 
        /*
@@ -676,6 +678,14 @@ tuplesort_begin_index_hash(Relation indexRel,
        state->reversedirection = reversedirection_index_hash;
 
        state->indexRel = indexRel;
+
+       /*
+        * We look up the index column's hash function just once, to avoid
+        * chewing lots of cycles in repeated index_getprocinfo calls.  This
+        * assumes that our caller holds the index relation open throughout the
+        * sort, else the pointer obtained here might cease to be valid.
+        */
+       state->hash_proc = index_getprocinfo(indexRel, 1, HASHPROC);
        state->hash_mask = hash_mask;
 
        MemoryContextSwitchTo(oldcontext);
@@ -2809,10 +2819,11 @@ comparetup_index_hash(const SortTuple *a, const SortTuple *b,
 
        /* Compute hash codes and mask off bits we don't want to sort by */
        Assert(!a->isnull1);
+       hash1 = DatumGetUInt32(FunctionCall1(state->hash_proc, a->datum1))
+               & state->hash_mask;
        Assert(!b->isnull1);
-
-       hash1 = _hash_datum2hashkey(state->indexRel, a->datum1) & state->hash_mask;
-       hash2 = _hash_datum2hashkey(state->indexRel, b->datum1) & state->hash_mask;
+       hash2 = DatumGetUInt32(FunctionCall1(state->hash_proc, b->datum1))
+               & state->hash_mask;
 
        if (hash1 > hash2)
                return 1;