From 0111438b450bd08ac98eaab2b780815a28a6c7ea Mon Sep 17 00:00:00 2001
From: "tsmith@sita.local" <>
Date: Tue, 2 Oct 2007 23:47:30 -0600
Subject: [PATCH] Bug #20358: InnoDB hang on the adaptive hash index latch in
 btr0sea.c

Add --skip-innodb-adaptive-hash-index option, which is a way to
work around the bug (by disabling the adaptive hash feature entirely).

This may be useful even once the bug is fixed, for benchmarking purposes.
There are some workloads for which the adaptive hash index is not effective.
---
 sql/ha_innodb.cc | 3 +++
 sql/ha_innodb.h  | 3 ++-
 sql/mysqld.cc    | 9 ++++++++-
 sql/set_var.cc   | 1 +
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/sql/ha_innodb.cc b/sql/ha_innodb.cc
index 2d47c42cf1d..86d3e930122 100644
--- a/sql/ha_innodb.cc
+++ b/sql/ha_innodb.cc
@@ -174,6 +174,7 @@ my_bool	innobase_file_per_table			= FALSE;
 my_bool innobase_locks_unsafe_for_binlog        = FALSE;
 my_bool innobase_rollback_on_timeout		= FALSE;
 my_bool innobase_create_status_file		= FALSE;
+my_bool innobase_adaptive_hash_index		= TRUE;
 
 static char *internal_innobase_data_file_path	= NULL;
 
@@ -1376,6 +1377,8 @@ innobase_init(void)
 	srv_use_doublewrite_buf = (ibool) innobase_use_doublewrite;
 	srv_use_checksums = (ibool) innobase_use_checksums;
 
+	srv_use_adaptive_hash_indexes = (ibool) innobase_adaptive_hash_index;
+
 	os_use_large_pages = (ibool) innobase_use_large_pages;
 	os_large_page_size = (ulint) innobase_large_page_size;
 
diff --git a/sql/ha_innodb.h b/sql/ha_innodb.h
index 585bc75fa36..3db983901b3 100644
--- a/sql/ha_innodb.h
+++ b/sql/ha_innodb.h
@@ -217,7 +217,8 @@ extern my_bool innobase_log_archive,
                innobase_use_native_aio,
 	       innobase_file_per_table, innobase_locks_unsafe_for_binlog,
 	       innobase_rollback_on_timeout,
-               innobase_create_status_file;
+               innobase_create_status_file,
+               innobase_adaptive_hash_index;
 extern my_bool innobase_very_fast_shutdown; /* set this to 1 just before
 					    calling innobase_end() if you want
 					    InnoDB to shut down without
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 08c2b60fa79..a6c9eeec65a 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -4829,7 +4829,8 @@ enum options_mysqld
   OPT_MERGE,
   OPT_INNODB_ROLLBACK_ON_TIMEOUT,
   OPT_SECURE_FILE_PRIV,
-  OPT_KEEP_FILES_ON_CREATE
+  OPT_KEEP_FILES_ON_CREATE,
+  OPT_INNODB_ADAPTIVE_HASH_INDEX
 };
 
 
@@ -5057,6 +5058,12 @@ Disable with --skip-innodb-checksums.", (gptr*) &innobase_use_checksums,
    "The common part for InnoDB table spaces.", (gptr*) &innobase_data_home_dir,
    (gptr*) &innobase_data_home_dir, 0, GET_STR, REQUIRED_ARG, 0, 0, 0, 0, 0,
    0},
+  {"innodb_adaptive_hash_index", OPT_INNODB_ADAPTIVE_HASH_INDEX,
+   "Enable InnoDB adaptive hash index (enabled by default).  "
+   "Disable with --skip-innodb-adaptive-hash-index.",
+   (gptr*) &innobase_adaptive_hash_index,
+   (gptr*) &innobase_adaptive_hash_index,
+   0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0, 0},
   {"innodb_doublewrite", OPT_INNODB_DOUBLEWRITE, "Enable InnoDB doublewrite buffer (enabled by default). \
 Disable with --skip-innodb-doublewrite.", (gptr*) &innobase_use_doublewrite,
    (gptr*) &innobase_use_doublewrite, 0, GET_BOOL, NO_ARG, 1, 0, 0, 0, 0, 0},
diff --git a/sql/set_var.cc b/sql/set_var.cc
index e1246617d84..268c82c2be2 100644
--- a/sql/set_var.cc
+++ b/sql/set_var.cc
@@ -901,6 +901,7 @@ struct show_var_st init_vars[]= {
   {sys_innodb_concurrency_tickets.name, (char*) &sys_innodb_concurrency_tickets, SHOW_SYS},
   {"innodb_data_file_path", (char*) &innobase_data_file_path,	    SHOW_CHAR_PTR},
   {"innodb_data_home_dir",  (char*) &innobase_data_home_dir,	    SHOW_CHAR_PTR},
+  {"innodb_adaptive_hash_index", (char*) &innobase_adaptive_hash_index, SHOW_MY_BOOL},
   {"innodb_doublewrite", (char*) &innobase_use_doublewrite, SHOW_MY_BOOL},
   {sys_innodb_fast_shutdown.name,(char*) &sys_innodb_fast_shutdown, SHOW_SYS},
   {"innodb_file_io_threads", (char*) &innobase_file_io_threads, SHOW_LONG },