Bug#16067973 DROP TABLE SLOW WHEN IT DECOMPRESS COMPRESSED-ONLY PAGES

buf_page_get_gen(): Do not attempt to decompress a compressed-only
page when mode == BUF_PEEK_IF_IN_POOL. This mode is only being used by
btr_search_drop_page_hash_when_freed(). There cannot be any adaptive
hash index pointing to a page that does not exist in uncompressed
format in the buffer pool.

innodb_buffer_pool_evict_update(): New function for debug builds, to handle
SET GLOBAL innodb_buffer_pool_evicted='uncompressed'
by evicting all uncompressed page frames of compressed tablespaces
from the buffer pool.

rb#1873 approved by Jimmy Yang

mysql-test/suite/sys_vars/r/innodb_buffer_pool_evict_basic.result

+SELECT @@global.innodb_buffer_pool_evict;
+@@global.innodb_buffer_pool_evict
+
+SET GLOBAL innodb_buffer_pool_evict = 'uncompressed';
+SELECT @@global.innodb_buffer_pool_evict;
+@@global.innodb_buffer_pool_evict
+

mysql-test/suite/sys_vars/t/innodb_buffer_pool_evict_basic.test

+-- source include/have_innodb_plugin.inc
+# This is a debug variable for now
+-- source include/have_debug.inc
+
+SELECT @@global.innodb_buffer_pool_evict;
+
+SET GLOBAL innodb_buffer_pool_evict = 'uncompressed';
+
+# Should always be empty.
+SELECT @@global.innodb_buffer_pool_evict;

storage/innodb_plugin/ChangeLog

+2013-01-21	The InnoDB Team
+
+	* buf/buf0buf.cc, handler/ha_innodb.cc:
+	Fix Bug#16067973 DROP TABLE IS SLOW WHEN IT DECOMPRESSES
+	COMPRESSED-ONLY PAGES
+
 2013-01-11	The InnoDB Team
 	* row/row0sel.c:
 	Fix Bug#16088883 KILLING A QUERY INSIDE INNODB CAUSES IT TO
@@ -6,7 +12,7 @@
 2012-12-18	The InnoDB Team
 
 	* include/univ.i:
-	Fix Bug#Bug#13463493 INNODB PLUGIN WERE CHANGED, BUT STILL USE THE
+	Fix Bug#13463493 INNODB PLUGIN WERE CHANGED, BUT STILL USE THE
 	SAME VERSION NUMBER 1.0.17
 
 2012-12-13	The InnoDB Team

storage/innodb_plugin/buf/buf0buf.c

 /*****************************************************************************
 
-Copyright (c) 1995, 2011, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 1995, 2013, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, Google Inc.
 
 Portions of this file contain modifications contributed and copyrighted by
@@ -1664,6 +1664,7 @@ buf_page_get_gen(
 	if (must_read && (mode == BUF_GET_IF_IN_POOL
 			  || mode == BUF_PEEK_IF_IN_POOL)) {
 		/* The page is only being read to buffer */
+null_exit:
 		buf_pool_mutex_exit();
 
 		return(NULL);
@@ -1678,6 +1679,14 @@ buf_page_get_gen(
 
 	case BUF_BLOCK_ZIP_PAGE:
 	case BUF_BLOCK_ZIP_DIRTY:
+		if (mode == BUF_PEEK_IF_IN_POOL) {
+			/* This mode is only used for dropping an
+			adaptive hash index.  There cannot be an
+			adaptive hash index for a compressed-only
+			page, so do not bother decompressing the page. */
+			goto null_exit;
+		}
+
 		bpage = &block->page;
 		/* Protect bpage->buf_fix_count. */
 		mutex_enter(&buf_pool_zip_mutex);

storage/innodb_plugin/handler/ha_innodb.cc

 /*****************************************************************************
 
-Copyright (c) 2000, 2011, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 2000, 2013, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, 2009 Google Inc.
 Copyright (c) 2009, Percona Inc.
 
@@ -10926,6 +10926,55 @@ innodb_change_buffering_update(
 		 *static_cast<const char*const*>(save);
 }
 
+#ifndef DBUG_OFF
+static char* srv_buffer_pool_evict;
+
+/****************************************************************//**
+Called on SET GLOBAL innodb_buffer_pool_evict=...
+Handles some values specially, to evict pages from the buffer pool.
+SET GLOBAL innodb_buffer_pool_evict='uncompressed'
+evicts all uncompressed page frames of compressed tablespaces. */
+static
+void
+innodb_buffer_pool_evict_update(
+/*============================*/
+	THD*			thd,	/*!< in: thread handle */
+	struct st_mysql_sys_var*var,	/*!< in: pointer to system variable */
+	void*			var_ptr,/*!< out: ignored */
+	const void*		save)	/*!< in: immediate result
+					from check function */
+{
+	if (const char* op = *static_cast<const char*const*>(save)) {
+		if (!strcmp(op, "uncompressed")) {
+			/* Evict all uncompressed pages of compressed
+			tables from the buffer pool. Keep the compressed
+			pages in the buffer pool. */
+
+			buf_pool_mutex_enter();
+
+			for (buf_block_t* block = UT_LIST_GET_LAST(
+				     buf_pool->unzip_LRU);
+			     block != NULL; ) {
+
+				buf_block_t*	prev_block
+					= UT_LIST_GET_PREV(unzip_LRU, block);
+				ut_ad(buf_block_get_state(block)
+				      == BUF_BLOCK_FILE_PAGE);
+				ut_ad(block->in_unzip_LRU_list);
+				ut_ad(block->page.in_LRU_list);
+
+				mutex_enter(&block->mutex);
+				buf_LRU_free_block(&block->page, FALSE);
+				mutex_exit(&block->mutex);
+				block = prev_block;
+			}
+
+			buf_pool_mutex_exit();
+		}
+	}
+}
+#endif /* !DBUG_OFF */
+
 static int show_innodb_vars(THD *thd, SHOW_VAR *var, char *buff)
 {
   innodb_export_status();
@@ -11128,6 +11177,13 @@ static MYSQL_SYSVAR_ULONG(autoextend_increment, srv_auto_extend_increment,
   "Data file autoextend increment in megabytes",
   NULL, NULL, 8L, 1L, 1000L, 0);
 
+#ifndef DBUG_OFF
+static MYSQL_SYSVAR_STR(buffer_pool_evict, srv_buffer_pool_evict,
+  PLUGIN_VAR_RQCMDARG,
+  "Evict pages from the InnoDB buffer pool.",
+  NULL, innodb_buffer_pool_evict_update, "");
+#endif /* !DBUG_OFF */
+
 static MYSQL_SYSVAR_LONGLONG(buffer_pool_size, innobase_buffer_pool_size,
   PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_READONLY,
   "The size of the memory buffer InnoDB uses to cache data and indexes of its tables.",
@@ -11300,6 +11356,9 @@ static MYSQL_SYSVAR_BOOL(trx_purge_view_update_only_debug,
 static struct st_mysql_sys_var* innobase_system_variables[]= {
   MYSQL_SYSVAR(additional_mem_pool_size),
   MYSQL_SYSVAR(autoextend_increment),
+#ifndef DBUG_OFF
+  MYSQL_SYSVAR(buffer_pool_evict),
+#endif /* !DBUG_OFF */
   MYSQL_SYSVAR(buffer_pool_size),
   MYSQL_SYSVAR(checksums),
   MYSQL_SYSVAR(commit_concurrency),