From 549e7644313ae0ac7f19083b4ec5a200d853184a Mon Sep 17 00:00:00 2001
From: vasil <>
Date: Wed, 9 Sep 2009 12:35:58 +0000
Subject: [PATCH] branches/zip:

Fix a bug in manipulating the variable innodb_old_blocks_pct:

for any value assigned it got that value -1, except for 75. When
assigned 75, it got 75.

  mysql> set global innodb_old_blocks_pct=15;
  Query OK, 0 rows affected (0.00 sec)

  mysql> show variables like 'innodb_old_blocks_pct';
  +-----------------------+-------+
  | Variable_name         | Value |
  +-----------------------+-------+
  | innodb_old_blocks_pct | 14    |
  +-----------------------+-------+
  1 row in set (0.00 sec)

  mysql> set global innodb_old_blocks_pct=75;
  Query OK, 0 rows affected (0.00 sec)

  mysql> show variables like 'innodb_old_blocks_pct';
  +-----------------------+-------+
  | Variable_name         | Value |
  +-----------------------+-------+
  | innodb_old_blocks_pct | 75    |
  +-----------------------+-------+

After the fix it gets exactly what was assigned.

Approved by:	Marko (via IM)
---
 buf/buf0lru.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/buf/buf0lru.c b/buf/buf0lru.c
index e7cf852e200..dd632ace4ac 100644
--- a/buf/buf0lru.c
+++ b/buf/buf0lru.c
@@ -1866,7 +1866,9 @@ buf_LRU_old_ratio_update(
 		buf_LRU_old_ratio = ratio;
 	}
 
-	return(ratio * 100 / BUF_LRU_OLD_RATIO_DIV);
+	/* the reverse of 
+	ratio = old_pct * BUF_LRU_OLD_RATIO_DIV / 100 */
+	return((uint) (ratio * 100 / (double) BUF_LRU_OLD_RATIO_DIV + 0.5));
 }
 
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