Merge XtraDB 8 into MariaDB.

1 files changed, 79 insertions, 38 deletions

diff --git a/storage/xtradb/include/buf0flu.h b/storage/xtradb/include/buf0flu.h
index 11a37351479..cac4bf9fe4b 100644
--- a/storage/xtradb/include/buf0flu.h
+++ b/storage/xtradb/include/buf0flu.h
@@ -16,7 +16,8 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 
 *****************************************************************************/
 
-/******************************************************
+/**************************************************//**
+@file include/buf0flu.h
 The database buffer pool flush algorithm
 
 Created 11/5/1995 Heikki Tuuri
@@ -26,25 +27,26 @@ Created 11/5/1995 Heikki Tuuri
 #define buf0flu_h
 
 #include "univ.i"
-#include "buf0types.h"
 #include "ut0byte.h"
+#ifndef UNIV_HOTBACKUP
 #include "mtr0types.h"
+#include "buf0types.h"
 
-/************************************************************************
+/********************************************************************//**
 Remove a block from the flush list of modified blocks. */
 UNIV_INTERN
 void
 buf_flush_remove(
 /*=============*/
-	buf_page_t*	bpage);	/* in: pointer to the block in question */
-/************************************************************************
+	buf_page_t*	bpage);	/*!< in: pointer to the block in question */
+/********************************************************************//**
 Updates the flush system data structures when a write is completed. */
 UNIV_INTERN
 void
 buf_flush_write_complete(
 /*=====================*/
-	buf_page_t*	bpage);	/* in: pointer to the block in question */
-/*************************************************************************
+	buf_page_t*	bpage);	/*!< in: pointer to the block in question */
+/*********************************************************************//**
 Flushes pages from the end of the LRU list if there is too small
 a margin of replaceable pages there. */
 UNIV_INTERN
@@ -52,50 +54,50 @@ void
 buf_flush_free_margin(
 /*=======================*/
 	ibool	wait);
-/************************************************************************
+#endif /* !UNIV_HOTBACKUP */
+/********************************************************************//**
 Initializes a page for writing to the tablespace. */
 UNIV_INTERN
 void
 buf_flush_init_for_writing(
 /*=======================*/
-	byte*		page,		/* in/out: page */
-	void*		page_zip_,	/* in/out: compressed page, or NULL */
-	ib_uint64_t	newest_lsn);	/* in: newest modification lsn
+	byte*		page,		/*!< in/out: page */
+	void*		page_zip_,	/*!< in/out: compressed page, or NULL */
+	ib_uint64_t	newest_lsn);	/*!< in: newest modification lsn
 					to the page */
-/***********************************************************************
+#ifndef UNIV_HOTBACKUP
+/*******************************************************************//**
 This utility flushes dirty blocks from the end of the LRU list or flush_list.
 NOTE 1: in the case of an LRU flush the calling thread may own latches to
 pages: to avoid deadlocks, this function must be written so that it cannot
 end up waiting for these latches! NOTE 2: in the case of a flush list flush,
-the calling thread is not allowed to own any latches on pages! */
+the calling thread is not allowed to own any latches on pages!
+@return number of blocks for which the write request was queued;
+ULINT_UNDEFINED if there was a flush of the same type already running */
 UNIV_INTERN
 ulint
 buf_flush_batch(
 /*============*/
-					/* out: number of blocks for which the
-					write request was queued;
-					ULINT_UNDEFINED if there was a flush
-					of the same type already running */
-	enum buf_flush	flush_type,	/* in: BUF_FLUSH_LRU or
+	enum buf_flush	flush_type,	/*!< in: BUF_FLUSH_LRU or
 					BUF_FLUSH_LIST; if BUF_FLUSH_LIST,
 					then the caller must not own any
 					latches on pages */
-	ulint		min_n,		/* in: wished minimum mumber of blocks
+	ulint		min_n,		/*!< in: wished minimum mumber of blocks
 					flushed (it is not guaranteed that the
 					actual number is that big, though) */
-	ib_uint64_t	lsn_limit);	/* in the case BUF_FLUSH_LIST all
+	ib_uint64_t	lsn_limit);	/*!< in the case BUF_FLUSH_LIST all
 					blocks whose oldest_modification is
 					smaller than this should be flushed
 					(if their number does not exceed
 					min_n), otherwise ignored */
-/**********************************************************************
+/******************************************************************//**
 Waits until a flush batch of the given type ends */
 UNIV_INTERN
 void
 buf_flush_wait_batch_end(
 /*=====================*/
-	enum buf_flush	type);	/* in: BUF_FLUSH_LRU or BUF_FLUSH_LIST */
-/************************************************************************
+	enum buf_flush	type);	/*!< in: BUF_FLUSH_LRU or BUF_FLUSH_LIST */
+/********************************************************************//**
 This function should be called at a mini-transaction commit, if a page was
 modified in it. Puts the block to the list of modified blocks, if it not
 already in it. */
@@ -103,46 +105,85 @@ UNIV_INLINE
 void
 buf_flush_note_modification(
 /*========================*/
-	buf_block_t*	block,	/* in: block which is modified */
-	mtr_t*		mtr);	/* in: mtr */
-/************************************************************************
+	buf_block_t*	block,	/*!< in: block which is modified */
+	mtr_t*		mtr);	/*!< in: mtr */
+/********************************************************************//**
 This function should be called when recovery has modified a buffer page. */
 UNIV_INLINE
 void
 buf_flush_recv_note_modification(
 /*=============================*/
-	buf_block_t*	block,		/* in: block which is modified */
-	ib_uint64_t	start_lsn,	/* in: start lsn of the first mtr in a
+	buf_block_t*	block,		/*!< in: block which is modified */
+	ib_uint64_t	start_lsn,	/*!< in: start lsn of the first mtr in a
 					set of mtr's */
-	ib_uint64_t	end_lsn);	/* in: end lsn of the last mtr in the
+	ib_uint64_t	end_lsn);	/*!< in: end lsn of the last mtr in the
 					set of mtr's */
-/************************************************************************
+/********************************************************************//**
 Returns TRUE if the file page block is immediately suitable for replacement,
-i.e., transition FILE_PAGE => NOT_USED allowed. */
+i.e., transition FILE_PAGE => NOT_USED allowed.
+@return	TRUE if can replace immediately */
 UNIV_INTERN
 ibool
 buf_flush_ready_for_replace(
 /*========================*/
-				/* out: TRUE if can replace immediately */
-	buf_page_t*	bpage);	/* in: buffer control block, must be
+	buf_page_t*	bpage);	/*!< in: buffer control block, must be
 				buf_page_in_file(bpage) and in the LRU list */
+
+/** @brief Statistics for selecting flush rate based on redo log
+generation speed.
+
+These statistics are generated for heuristics used in estimating the
+rate at which we should flush the dirty blocks to avoid bursty IO
+activity. Note that the rate of flushing not only depends on how many
+dirty pages we have in the buffer pool but it is also a fucntion of
+how much redo the workload is generating and at what rate. */
+
+struct buf_flush_stat_struct
+{
+	ib_uint64_t	redo;		/**< amount of redo generated. */
+	ulint		n_flushed;	/**< number of pages flushed. */
+};
+
+/** Statistics for selecting flush rate of dirty pages. */
+typedef struct buf_flush_stat_struct buf_flush_stat_t;
+/*********************************************************************
+Update the historical stats that we are collecting for flush rate
+heuristics at the end of each interval. */
+UNIV_INTERN
+void
+buf_flush_stat_update(void);
+/*=======================*/
+/*********************************************************************
+Determines the fraction of dirty pages that need to be flushed based
+on the speed at which we generate redo log. Note that if redo log
+is generated at significant rate without a corresponding increase
+in the number of dirty pages (for example, an in-memory workload)
+it can cause IO bursts of flushing. This function implements heuristics
+to avoid this burstiness.
+@return	number of dirty pages to be flushed / second */
+UNIV_INTERN
+ulint
+buf_flush_get_desired_flush_rate(void);
+/*==================================*/
+
 #if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
-/**********************************************************************
-Validates the flush list. */
+/******************************************************************//**
+Validates the flush list.
+@return	TRUE if ok */
 UNIV_INTERN
 ibool
 buf_flush_validate(void);
 /*====================*/
-		/* out: TRUE if ok */
 #endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
 
-/* When buf_flush_free_margin is called, it tries to make this many blocks
+/** When buf_flush_free_margin is called, it tries to make this many blocks
 available to replacement in the free list and at the end of the LRU list (to
 make sure that a read-ahead batch can be read efficiently in a single
 sweep). */
-
 #define BUF_FLUSH_FREE_BLOCK_MARGIN	(5 + BUF_READ_AHEAD_AREA)
+/** Extra margin to apply above BUF_FLUSH_FREE_BLOCK_MARGIN */
 #define BUF_FLUSH_EXTRA_MARGIN		(BUF_FLUSH_FREE_BLOCK_MARGIN / 4 + 100)
+#endif /* !UNIV_HOTBACKUP */
 
 #ifndef UNIV_NONINL
 #include "buf0flu.ic"