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*****************************************************************************/

/**************************************************//**
@file include/log0recv.h
Recovery

Created 9/20/1997 Heikki Tuuri
*******************************************************/

#ifndef log0recv_h
#define log0recv_h

#include "univ.i"
#include "ut0byte.h"
#include "buf0types.h"
#include "hash0hash.h"
#include "log0log.h"
#include "mtr0types.h"
#include "ut0new.h"

#include <list>
#include <vector>

/** Is recv_writer_thread active? */
extern bool	recv_writer_thread_active;

/** @return whether recovery is currently running. */
#define recv_recovery_is_on() recv_recovery_on

/** Find the latest checkpoint in the log header.
@param[out]	max_field	LOG_CHECKPOINT_1 or LOG_CHECKPOINT_2
@return error code or DB_SUCCESS */
dberr_t
recv_find_max_checkpoint(ulint* max_field)
	MY_ATTRIBUTE((nonnull, warn_unused_result));

/** Apply the hashed log records to the page, if the page lsn is less than the
lsn of a log record.
@param just_read_in	whether the page recently arrived to the I/O handler
@param block		the page in the buffer pool */
void
recv_recover_page(bool just_read_in, buf_block_t* block);

/** Start recovering from a redo log checkpoint.
@see recv_recovery_from_checkpoint_finish
@param[in]	flush_lsn	FIL_PAGE_FILE_FLUSH_LSN
of first system tablespace page
@return error code or DB_SUCCESS */
dberr_t
recv_recovery_from_checkpoint_start(
	lsn_t	flush_lsn);
/** Complete recovery from a checkpoint. */
void
recv_recovery_from_checkpoint_finish(void);
/********************************************************//**
Initiates the rollback of active transactions. */
void
recv_recovery_rollback_active(void);
/*===============================*/
/******************************************************//**
Resets the logs. The contents of log files will be lost! */
void
recv_reset_logs(
/*============*/
	lsn_t		lsn);		/*!< in: reset to this lsn
					rounded up to be divisible by
					OS_FILE_LOG_BLOCK_SIZE, after
					which we add
					LOG_BLOCK_HDR_SIZE */
/** Clean up after recv_sys_init() */
void
recv_sys_close();
/** Initialize the redo log recovery subsystem. */
void
recv_sys_init();
/********************************************************//**
Frees the recovery system. */
void
recv_sys_debug_free(void);
/*=====================*/

/** Read a log segment to a buffer.
@param[out]	buf		buffer
@param[in]	group		redo log files
@param[in, out]	start_lsn	in : read area start, out: the last read valid lsn
@param[in]	end_lsn		read area end
@param[out] invalid_block - invalid, (maybe incompletely written) block encountered
@return	false, if invalid block encountered (e.g checksum mismatch), true otherwise */
bool
log_group_read_log_seg(
	byte*			buf,
	const log_group_t*	group,
	lsn_t*			start_lsn,
	lsn_t			end_lsn);

/********************************************************//**
Reset the state of the recovery system variables. */
void
recv_sys_var_init(void);
/*===================*/

/** Apply the hash table of stored log records to persistent data pages.
@param[in]	last_batch	whether the change buffer merge will be
				performed as part of the operation */
void
recv_apply_hashed_log_recs(bool last_batch);

/** Block of log record data */
struct recv_data_t{
	recv_data_t*	next;	/*!< pointer to the next block or NULL */
				/*!< the log record data is stored physically
				immediately after this struct, max amount
				RECV_DATA_BLOCK_SIZE bytes of it */
};

/** Stored log record struct */
struct recv_t{
	mlog_id_t	type;	/*!< log record type */
	ulint		len;	/*!< log record body length in bytes */
	recv_data_t*	data;	/*!< chain of blocks containing the log record
				body */
	lsn_t		start_lsn;/*!< start lsn of the log segment written by
				the mtr which generated this log record: NOTE
				that this is not necessarily the start lsn of
				this log record */
	lsn_t		end_lsn;/*!< end lsn of the log segment written by
				the mtr which generated this log record: NOTE
				that this is not necessarily the end lsn of
				this log record */
	UT_LIST_NODE_T(recv_t)
			rec_list;/*!< list of log records for this page */
};

/** States of recv_addr_t */
enum recv_addr_state {
	/** not yet processed */
	RECV_NOT_PROCESSED,
	/** page is being read */
	RECV_BEING_READ,
	/** log records are being applied on the page */
	RECV_BEING_PROCESSED,
	/** log records have been applied on the page */
	RECV_PROCESSED,
	/** log records have been discarded because the tablespace
	does not exist */
	RECV_DISCARDED
};

/** Hashed page file address struct */
struct recv_addr_t{
	enum recv_addr_state state;
				/*!< recovery state of the page */
	unsigned	space:32;/*!< space id */
	unsigned	page_no:32;/*!< page number */
	UT_LIST_BASE_NODE_T(recv_t)
			rec_list;/*!< list of log records for this page */
	hash_node_t	addr_hash;/*!< hash node in the hash bucket chain */
};

struct recv_dblwr_t {
	/** Add a page frame to the doublewrite recovery buffer. */
	void add(byte* page) {
		pages.push_back(page);
	}

	/** Find a doublewrite copy of a page.
	@param[in]	space_id	tablespace identifier
	@param[in]	page_no		page number
	@return	page frame
	@retval NULL if no page was found */
	const byte* find_page(ulint space_id, ulint page_no);

	typedef std::list<byte*, ut_allocator<byte*> >	list;

	/** Recovered doublewrite buffer page frames */
	list	pages;
};

/** Recovery system data structure */
struct recv_sys_t{
	ib_mutex_t		mutex;	/*!< mutex protecting the fields apply_log_recs,
				n_addrs, and the state field in each recv_addr
				struct */
	ib_mutex_t		writer_mutex;/*!< mutex coordinating
				flushing between recv_writer_thread and
				the recovery thread. */
	os_event_t		flush_start;/*!< event to acticate
				page cleaner threads */
	os_event_t		flush_end;/*!< event to signal that the page
				cleaner has finished the request */
	buf_flush_t		flush_type;/*!< type of the flush request.
				BUF_FLUSH_LRU: flush end of LRU, keeping free blocks.
				BUF_FLUSH_LIST: flush all of blocks. */
	ibool		apply_log_recs;
				/*!< this is TRUE when log rec application to
				pages is allowed; this flag tells the
				i/o-handler if it should do log record
				application */
	ibool		apply_batch_on;
				/*!< this is TRUE when a log rec application
				batch is running */
	byte*		buf;	/*!< buffer for parsing log records */
	ulint		len;	/*!< amount of data in buf */
	lsn_t		parse_start_lsn;
				/*!< this is the lsn from which we were able to
				start parsing log records and adding them to
				the hash table; zero if a suitable
				start point not found yet */
	lsn_t		scanned_lsn;
				/*!< the log data has been scanned up to this
				lsn */
	ulint		scanned_checkpoint_no;
				/*!< the log data has been scanned up to this
				checkpoint number (lowest 4 bytes) */
	ulint		recovered_offset;
				/*!< start offset of non-parsed log records in
				buf */
	lsn_t		recovered_lsn;
				/*!< the log records have been parsed up to
				this lsn */
	bool		found_corrupt_log;
				/*!< set when finding a corrupt log
				block or record, or there is a log
				parsing buffer overflow */
	bool		found_corrupt_fs;
				/*!< set when an inconsistency with
				the file system contents is detected
				during log scan or apply */
	lsn_t		mlog_checkpoint_lsn;
				/*!< the LSN of a MLOG_CHECKPOINT
				record, or 0 if none was parsed */
	/** the time when progress was last reported */
	ib_time_t	progress_time;
	mem_heap_t*	heap;	/*!< memory heap of log records and file
				addresses*/
	hash_table_t*	addr_hash;/*!< hash table of file addresses of pages */
	ulint		n_addrs;/*!< number of not processed hashed file
				addresses in the hash table */

	recv_dblwr_t	dblwr;

	/** Determine whether redo log recovery progress should be reported.
	@param[in]	time	the current time
	@return	whether progress should be reported
		(the last report was at least 15 seconds ago) */
	bool report(ib_time_t time)
	{
		if (time - progress_time < 15) {
			return false;
		}

		progress_time = time;
		return true;
	}
};

/** The recovery system */
extern recv_sys_t*	recv_sys;

/** TRUE when applying redo log records during crash recovery; FALSE
otherwise.  Note that this is FALSE while a background thread is
rolling back incomplete transactions. */
extern volatile bool	recv_recovery_on;
/** If the following is TRUE, the buffer pool file pages must be invalidated
after recovery and no ibuf operations are allowed; this becomes TRUE if
the log record hash table becomes too full, and log records must be merged
to file pages already before the recovery is finished: in this case no
ibuf operations are allowed, as they could modify the pages read in the
buffer pool before the pages have been recovered to the up-to-date state.

TRUE means that recovery is running and no operations on the log files
are allowed yet: the variable name is misleading. */
extern bool		recv_no_ibuf_operations;
/** TRUE when recv_init_crash_recovery() has been called. */
extern bool		recv_needed_recovery;
#ifdef UNIV_DEBUG
/** TRUE if writing to the redo log (mtr_commit) is forbidden.
Protected by log_sys->mutex. */
extern bool		recv_no_log_write;
#endif /* UNIV_DEBUG */

/** TRUE if buf_page_is_corrupted() should check if the log sequence
number (FIL_PAGE_LSN) is in the future.  Initially FALSE, and set by
recv_recovery_from_checkpoint_start(). */
extern bool		recv_lsn_checks_on;

/** Size of the parsing buffer; it must accommodate RECV_SCAN_SIZE many
times! */
#define RECV_PARSING_BUF_SIZE	(2 * 1024 * 1024)

/** Size of block reads when the log groups are scanned forward to do a
roll-forward */
#define RECV_SCAN_SIZE		(4 * UNIV_PAGE_SIZE)

/** This many frames must be left free in the buffer pool when we scan
the log and store the scanned log records in the buffer pool: we will
use these free frames to read in pages when we start applying the
log records to the database. */
extern ulint	recv_n_pool_free_frames;

#endif