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 
 
+#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;