From 2c9d2cf671d33f598dcec7eb5604f98638c96490 Mon Sep 17 00:00:00 2001
From: "sergefp@mysql.com" <>
Date: Wed, 8 Sep 2004 02:07:53 +0400
Subject: Fix for bug#5138: hash indexes on heap tables support statistics. 
 KEY::rec_per_key is updated every time 1/HEAP_STATS_UPDATE_THRESHOLD part of
 table records has been changed.

---
 heap/hp_hash.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

(limited to 'heap/hp_hash.c')

diff --git a/heap/hp_hash.c b/heap/hp_hash.c
index 71eecc8bdf2..2108765cc7f 100644
--- a/heap/hp_hash.c
+++ b/heap/hp_hash.c
@@ -196,7 +196,18 @@ byte *hp_search_next(HP_INFO *info, HP_KEYDEF *keyinfo, const byte *key,
 }
 
 
-	/* Calculate pos according to keys */
+/*
+  Calculate position number for hash value.
+  SYNOPSIS
+    hp_mask()
+      hashnr     Hash value
+      buffmax    Value such that
+                 2^(n-1) < maxlength <= 2^n = buffmax
+      maxlength  
+  
+  RETURN
+    Array index, in [0..maxlength)
+*/
 
 ulong hp_mask(ulong hashnr, ulong buffmax, ulong maxlength)
 {
@@ -205,7 +216,12 @@ ulong hp_mask(ulong hashnr, ulong buffmax, ulong maxlength)
 }
 
 
-	/* Change link from pos to new_link */
+/*
+  Change
+    next_link -> ... -> X -> pos
+  to
+    next_link -> ... -> X -> newlink
+*/
 
 void hp_movelink(HASH_INFO *pos, HASH_INFO *next_link, HASH_INFO *newlink)
 {
-- 
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