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/**************************************************//**
@file include/buf0flu.h
The database buffer pool flush algorithm

Created 11/5/1995 Heikki Tuuri
*******************************************************/

#pragma once

#include "ut0byte.h"
#include "log0log.h"
#include "buf0buf.h"

/** Number of pages flushed via LRU. Protected by buf_pool.mutex.
Also included in buf_pool.stat.n_pages_written. */
extern ulint buf_lru_flush_page_count;
/** Number of pages freed without flushing. Protected by buf_pool.mutex. */
extern ulint buf_lru_freed_page_count;

/** Flag indicating if the page_cleaner is in active state. */
extern Atomic_relaxed<bool> buf_page_cleaner_is_active;

/** Remove all dirty pages belonging to a given tablespace when we are
deleting the data file of that tablespace.
The pages still remain a part of LRU and are evicted from
the list as they age towards the tail of the LRU.
@param id    tablespace identifier */
void buf_flush_remove_pages(uint32_t id) noexcept;

/** Relocate a buffer control block in buf_pool.flush_list.
@param bpage   control block being moved
@param dpage   destination block; the page contents has already been copied */
ATTRIBUTE_COLD
void buf_flush_relocate_on_flush_list(buf_page_t *bpage, buf_page_t *dpage)
  noexcept;
/** Complete write of a file page from buf_pool.
@param request write request
@param error   whether the write may have failed */
void buf_page_write_complete(const IORequest &request, bool error) noexcept;

/** Assign the full crc32 checksum for non-compressed page.
@param[in,out]	page	page to be updated */
void buf_flush_assign_full_crc32_checksum(byte* page) noexcept;

/** Initialize a page for writing to the tablespace.
@param[in]	block			buffer block; NULL if bypassing the buffer pool
@param[in,out]	page			page frame
@param[in,out]	page_zip_		compressed page, or NULL if uncompressed
@param[in]	use_full_checksum	whether tablespace uses full checksum */
void
buf_flush_init_for_writing(
	const buf_block_t*	block,
	byte*			page,
	void*			page_zip_,
	bool			use_full_checksum) noexcept;

/** Try to flush dirty pages that belong to a given tablespace.
@param space       tablespace
@param n_flushed   number of pages written
@return whether the flush for some pages might not have been initiated */
bool buf_flush_list_space(fil_space_t *space, ulint *n_flushed= nullptr)
  noexcept
  MY_ATTRIBUTE((warn_unused_result));

/** Wait until all persistent pages are flushed up to a limit.
@param sync_lsn   minimum checkpoint
@param checkpoint whether an empty checkpoint needs to be written */
ATTRIBUTE_COLD void buf_flush_wait(lsn_t sync_lsn, bool checkpoint) noexcept;
/** Initiate more eager page flushing if the log checkpoint age is too old.
@param lsn      buf_pool.get_oldest_modification(LSN_MAX) target
@param furious  true=furious flushing, false=limit to innodb_io_capacity */
ATTRIBUTE_COLD void buf_flush_ahead(lsn_t lsn, bool furious) noexcept;

/** Initialize page_cleaner. */
ATTRIBUTE_COLD void buf_flush_page_cleaner_init() noexcept;

#ifdef UNIV_DEBUG
/** Validate the flush list. */
void buf_flush_validate() noexcept;
#endif /* UNIV_DEBUG */

/** Wait for the persistent data to be written out.
NOTE: The calling thread is not allowed to hold any buffer page latches!
@param lsn        minimum checkpoint to wait for
@param checkpoint whether an empty checkpoint needs to be written */
ATTRIBUTE_COLD void buf_flush_sync_batch(lsn_t lsn, bool checkpoint) noexcept;
