db.h

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	u_int32_t st_gen;		/* Current generation number. */
	u_int32_t st_egen;		/* Current election gen number. */
	u_int32_t st_log_duplicated;	/* Log records received multiply.+ */
	u_int32_t st_log_queued;	/* Log records currently queued.+ */
	u_int32_t st_log_queued_max;	/* Max. log records queued at once.+ */
	u_int32_t st_log_queued_total;	/* Total # of log recs. ever queued.+ */
	u_int32_t st_log_records;	/* Log records received and put.+ */
	u_int32_t st_log_requested;	/* Log recs. missed and requested.+ */
	int st_master;			/* Env. ID of the current master. */
	u_int32_t st_master_changes;	/* # of times we've switched masters. */
	u_int32_t st_msgs_badgen;	/* Messages with a bad generation #.+ */
	u_int32_t st_msgs_processed;	/* Messages received and processed.+ */
	u_int32_t st_msgs_recover;	/* Messages ignored because this site
					   was a client in recovery.+ */
	u_int32_t st_msgs_send_failures;/* # of failed message sends.+ */
	u_int32_t st_msgs_sent;		/* # of successful message sends.+ */
	u_int32_t st_newsites;		/* # of NEWSITE msgs. received.+ */
	int st_nsites;			/* Current number of sites we will
					   assume during elections. */
	u_int32_t st_nthrottles;	/* # of times we were throttled. */
	u_int32_t st_outdated;		/* # of times we detected and returned
					   an OUTDATED condition.+ */
	u_int32_t st_pg_duplicated;	/* Pages received multiply.+ */
	u_int32_t st_pg_records;	/* Pages received and stored.+ */
	u_int32_t st_pg_requested;	/* Pages missed and requested.+ */
	u_int32_t st_startup_complete;	/* Site completed client sync-up. */
	u_int32_t st_txns_applied;	/* # of transactions applied.+ */

	/* Elections generally. */
	u_int32_t st_elections;		/* # of elections held.+ */
	u_int32_t st_elections_won;	/* # of elections won by this site.+ */

	/* Statistics about an in-progress election. */
	int st_election_cur_winner;	/* Current front-runner. */
	u_int32_t st_election_gen;	/* Election generation number. */
	DB_LSN st_election_lsn;		/* Max. LSN of current winner. */
	int st_election_nsites;		/* # of "registered voters". */
	int st_election_nvotes;		/* # of "registered voters" needed. */
	int st_election_priority;	/* Current election priority. */
	int st_election_status;		/* Current election status. */
	u_int32_t st_election_tiebreaker;/* Election tiebreaker value. */
	int st_election_votes;		/* Votes received in this round. */
};
/*
 * The storage record for a sequence.
 */
struct __db_seq_record {
	u_int32_t	seq_version;	/* Version size/number. */
#define	DB_SEQ_DEC		0x00000001	/* Decrement sequence. */
#define	DB_SEQ_INC		0x00000002	/* Increment sequence. */
#define	DB_SEQ_RANGE_SET	0x00000004	/* Range set (internal). */
#define	DB_SEQ_WRAP		0x00000008	/* Wrap sequence at min/max. */
	u_int32_t	flags;		/* Flags. */
	db_seq_t	seq_value;	/* Current value. */
	db_seq_t	seq_max;	/* Max permitted. */
	db_seq_t	seq_min;	/* Min permitted. */
};

/*
 * Handle for a sequence object.
 */
struct __db_sequence {
	DB		*seq_dbp;	/* DB handle for this sequence. */
	DB_MUTEX	*seq_mutexp;	/* Mutex if sequence is threaded. */
	DB_SEQ_RECORD	*seq_rp;	/* Pointer to current data. */
	DB_SEQ_RECORD	seq_record;	/* Data from DB_SEQUENCE. */
	int32_t		seq_cache_size; /* Number of values cached. */
	db_seq_t	seq_last_value;	/* Last value cached. */
	DBT		seq_key;	/* DBT pointing to sequence key. */
	DBT		seq_data;	/* DBT pointing to seq_record. */

	/* API-private structure: used by C++ and Java. */
	void		*api_internal;

	int		(*close) __P((DB_SEQUENCE *, u_int32_t));
	int		(*get) __P((DB_SEQUENCE *,
			      DB_TXN *, int32_t, db_seq_t *, u_int32_t));
	int		(*get_cachesize) __P((DB_SEQUENCE *, int32_t *));
	int		(*get_db) __P((DB_SEQUENCE *, DB **));
	int		(*get_flags) __P((DB_SEQUENCE *, u_int32_t *));
	int		(*get_key) __P((DB_SEQUENCE *, DBT *));
	int		(*get_range) __P((DB_SEQUENCE *,
			     db_seq_t *, db_seq_t *));
	int		(*initial_value) __P((DB_SEQUENCE *, db_seq_t));
	int		(*open) __P((DB_SEQUENCE *,
			    DB_TXN *, DBT *, u_int32_t));
	int		(*remove) __P((DB_SEQUENCE *, DB_TXN *, u_int32_t));
	int		(*set_cachesize) __P((DB_SEQUENCE *, int32_t));
	int		(*set_flags) __P((DB_SEQUENCE *, u_int32_t));
	int		(*set_range) __P((DB_SEQUENCE *, db_seq_t, db_seq_t));
	int		(*stat) __P((DB_SEQUENCE *,
			    DB_SEQUENCE_STAT **, u_int32_t));
	int		(*stat_print) __P((DB_SEQUENCE *, u_int32_t));
};

struct __db_seq_stat {
	u_int32_t st_wait;	  /* Sequence lock granted without wait. */
	u_int32_t st_nowait;	  /* Sequence lock granted after wait. */
	db_seq_t  st_current;	  /* Current value in db. */
	db_seq_t  st_value;	  /* Current cached value. */
	db_seq_t  st_last_value;  /* Last cached value. */
	db_seq_t  st_min;	  /* Minimum value. */
	db_seq_t  st_max;	  /* Maximum value. */
	int32_t   st_cache_size;  /* Cache size. */
	u_int32_t st_flags;	  /* Flag value. */
};

/*******************************************************
 * Access methods.
 *******************************************************/
typedef enum {
	DB_BTREE=1,
	DB_HASH=2,
	DB_RECNO=3,
	DB_QUEUE=4,
	DB_UNKNOWN=5			/* Figure it out on open. */
} DBTYPE;

#define	DB_RENAMEMAGIC	0x030800	/* File has been renamed. */

#define	DB_BTREEVERSION	9		/* Current btree version. */
#define	DB_BTREEOLDVER	8		/* Oldest btree version supported. */
#define	DB_BTREEMAGIC	0x053162

#define	DB_HASHVERSION	8		/* Current hash version. */
#define	DB_HASHOLDVER	7		/* Oldest hash version supported. */
#define	DB_HASHMAGIC	0x061561

#define	DB_QAMVERSION	4		/* Current queue version. */
#define	DB_QAMOLDVER	3		/* Oldest queue version supported. */
#define	DB_QAMMAGIC	0x042253

#define	DB_SEQUENCE_VERSION 1		/* Current sequence version. */

/*
 * DB access method and cursor operation values.  Each value is an operation
 * code to which additional bit flags are added.
 */
#define	DB_AFTER		 1	/* c_put() */
#define	DB_APPEND		 2	/* put() */
#define	DB_BEFORE		 3	/* c_put() */
#define	DB_CACHED_COUNTS	 4	/* stat() */
#define	DB_CONSUME		 5	/* get() */
#define	DB_CONSUME_WAIT		 6	/* get() */
#define	DB_CURRENT		 7	/* c_get(), c_put(), DB_LOGC->get() */
#define	DB_FAST_STAT		 8	/* stat() */
#define	DB_FIRST		 9	/* c_get(), DB_LOGC->get() */
#define	DB_GET_BOTH		10	/* get(), c_get() */
#define	DB_GET_BOTHC		11	/* c_get() (internal) */
#define	DB_GET_BOTH_RANGE	12	/* get(), c_get() */
#define	DB_GET_RECNO		13	/* c_get() */
#define	DB_JOIN_ITEM		14	/* c_get(); do not do primary lookup */
#define	DB_KEYFIRST		15	/* c_put() */
#define	DB_KEYLAST		16	/* c_put() */
#define	DB_LAST			17	/* c_get(), DB_LOGC->get() */
#define	DB_NEXT			18	/* c_get(), DB_LOGC->get() */
#define	DB_NEXT_DUP		19	/* c_get() */
#define	DB_NEXT_NODUP		20	/* c_get() */
#define	DB_NODUPDATA		21	/* put(), c_put() */
#define	DB_NOOVERWRITE		22	/* put() */
#define	DB_NOSYNC		23	/* close() */
#define	DB_POSITION		24	/* c_dup() */
#define	DB_PREV			25	/* c_get(), DB_LOGC->get() */
#define	DB_PREV_NODUP		26	/* c_get(), DB_LOGC->get() */
#define	DB_RECORDCOUNT		27	/* stat() */
#define	DB_SET			28	/* c_get(), DB_LOGC->get() */
#define	DB_SET_LOCK_TIMEOUT	29	/* set_timout() */
#define	DB_SET_RANGE		30	/* c_get() */
#define	DB_SET_RECNO		31	/* get(), c_get() */
#define	DB_SET_TXN_NOW		32	/* set_timout() (internal) */
#define	DB_SET_TXN_TIMEOUT	33	/* set_timout() */
#define	DB_UPDATE_SECONDARY	34	/* c_get(), c_del() (internal) */
#define	DB_WRITECURSOR		35	/* cursor() */
#define	DB_WRITELOCK		36	/* cursor() (internal) */

/* This has to change when the max opcode hits 255. */
#define	DB_OPFLAGS_MASK	0x000000ff	/* Mask for operations flags. */

/*
 * Masks for flags that can be OR'd into DB access method and cursor
 * operation values.
 *
 *	DB_DIRTY_READ	0x04000000	   Dirty Read. */
#define	DB_MULTIPLE	0x08000000	/* Return multiple data values. */
#define	DB_MULTIPLE_KEY	0x10000000	/* Return multiple data/key pairs. */
#define	DB_RMW		0x20000000	/* Acquire write flag immediately. */

/*
 * DB (user visible) error return codes.
 *
 * !!!
 * For source compatibility with DB 2.X deadlock return (EAGAIN), use the
 * following:
 *	#include <errno.h>
 *	#define DB_LOCK_DEADLOCK EAGAIN
 *
 * !!!
 * We don't want our error returns to conflict with other packages where
 * possible, so pick a base error value that's hopefully not common.  We
 * document that we own the error name space from -30,800 to -30,999.
 */
/* DB (public) error return codes. */
#define	DB_BUFFER_SMALL		(-30999)/* User memory too small for return. */
#define	DB_DONOTINDEX		(-30998)/* "Null" return from 2ndary callbk. */
#define	DB_KEYEMPTY		(-30997)/* Key/data deleted or never created. */
#define	DB_KEYEXIST		(-30996)/* The key/data pair already exists. */
#define	DB_LOCK_DEADLOCK	(-30995)/* Deadlock. */
#define	DB_LOCK_NOTGRANTED	(-30994)/* Lock unavailable. */
#define	DB_LOG_BUFFER_FULL	(-30993)/* In-memory log buffer full. */
#define	DB_NOSERVER		(-30992)/* Server panic return. */
#define	DB_NOSERVER_HOME	(-30991)/* Bad home sent to server. */
#define	DB_NOSERVER_ID		(-30990)/* Bad ID sent to server. */
#define	DB_NOTFOUND		(-30989)/* Key/data pair not found (EOF). */
#define	DB_OLD_VERSION		(-30988)/* Out-of-date version. */
#define	DB_PAGE_NOTFOUND	(-30987)/* Requested page not found. */
#define	DB_REP_DUPMASTER	(-30986)/* There are two masters. */
#define	DB_REP_HANDLE_DEAD	(-30985)/* Rolled back a commit. */
#define	DB_REP_HOLDELECTION	(-30984)/* Time to hold an election. */
#define	DB_REP_ISPERM		(-30983)/* Cached not written perm written.*/
#define	DB_REP_NEWMASTER	(-30982)/* We have learned of a new master. */
#define	DB_REP_NEWSITE		(-30981)/* New site entered system. */
#define	DB_REP_NOTPERM		(-30980)/* Permanent log record not written. */
#define	DB_REP_STARTUPDONE	(-30979)/* Client startup complete. */
#define	DB_REP_UNAVAIL		(-30978)/* Site cannot currently be reached. */
#define	DB_RUNRECOVERY		(-30977)/* Panic return. */
#define	DB_SECONDARY_BAD	(-30976)/* Secondary index corrupt. */
#define	DB_VERIFY_BAD		(-30975)/* Verify failed; bad format. */
#define	DB_VERSION_MISMATCH	(-30974)/* Environment version mismatch. */

/* DB (private) error return codes. */
#define	DB_ALREADY_ABORTED	(-30899)
#define	DB_DELETED		(-30898)/* Recovery file marked deleted. */
#define	DB_LOCK_NOTEXIST	(-30897)/* Object to lock is gone. */
#define	DB_NEEDSPLIT		(-30896)/* Page needs to be split. */
#define	DB_REP_EGENCHG		(-30895)/* Egen changed while in election. */
#define	DB_REP_LOGREADY		(-30894)/* Rep log ready for recovery. */
#define	DB_REP_PAGEDONE		(-30893)/* This page was already done. */
#define	DB_SURPRISE_KID		(-30892)/* Child commit where parent
					   didn't know it was a parent. */
#define	DB_SWAPBYTES		(-30891)/* Database needs byte swapping. */
#define	DB_TIMEOUT		(-30890)/* Timed out waiting for election. */
#define	DB_TXN_CKP		(-30889)/* Encountered ckp record in log. */
#define	DB_VERIFY_FATAL		(-30888)/* DB->verify cannot proceed. */

/* Database handle. */
struct __db {
	/*******************************************************
	 * Public: owned by the application.
	 *******************************************************/
	u_int32_t pgsize;		/* Database logical page size. */

					/* Callbacks. */
	int (*db_append_recno) __P((DB *, DBT *, db_recno_t));
	void (*db_feedback) __P((DB *, int, int));
	int (*dup_compare) __P((DB *, const DBT *, const DBT *));

	void	*app_private;		/* Application-private handle. */

	/*******************************************************
	 * Private: owned by DB.
	 *******************************************************/
	DB_ENV	*dbenv;			/* Backing environment. */

	DBTYPE	 type;			/* DB access method type. */

	DB_MPOOLFILE *mpf;		/* Backing buffer pool. */

	DB_MUTEX *mutexp;		/* Synchronization for free threading */

	char *fname, *dname;		/* File/database passed to DB->open. */
	u_int32_t open_flags;		/* Flags passed to DB->open. */

	u_int8_t fileid[DB_FILE_ID_LEN];/* File's unique ID for locking. */

	u_int32_t adj_fileid;		/* File's unique ID for curs. adj. */

#define	DB_LOGFILEID_INVALID	-1
	FNAME *log_filename;		/* File's naming info for logging. */

	db_pgno_t meta_pgno;		/* Meta page number */
	u_int32_t lid;			/* Locker id for handle locking. */
	u_int32_t cur_lid;		/* Current handle lock holder. */
	u_int32_t associate_lid;	/* Locker id for DB->associate call. */
	DB_LOCK	handle_lock;		/* Lock held on this handle. */

	u_int	 cl_id;			/* RPC: remote client id. */

	time_t	 timestamp;		/* Handle timestamp for replication. */

	/*
	 * Returned data memory for DB->get() and friends.
	 */
	DBT	 my_rskey;		/* Secondary key. */
	DBT	 my_rkey;		/* [Primary] key. */
	DBT	 my_rdata;		/* Data. */

	/*
	 * !!!
	 * Some applications use DB but implement their own locking outside of
	 * DB.  If they're using fcntl(2) locking on the underlying database
	 * file, and we open and close a file descriptor for that file, we will
	 * discard their locks.  The DB_FCNTL_LOCKING flag to DB->open is an
	 * undocumented interface to support this usage which leaves any file
	 * descriptors we open until DB->close.  This will only work with the
	 * DB->open interface and simple caches, e.g., creating a transaction
	 * thread may open/close file descriptors this flag doesn't protect.
	 * Locking with fcntl(2) on a file that you don't own is a very, very
	 * unsafe thing to do.  'Nuff said.
	 */
	DB_FH	*saved_open_fhp;	/* Saved file handle. */

	/*
	 * Linked list of DBP's, linked from the DB_ENV, used to keep track
	 * of all open db handles for cursor adjustment.
	 *
	 * !!!
	 * Explicit representations of structures from queue.h.
	 * LIST_ENTRY(__db) dblistlinks;
	 */
	struct {
		struct __db *le_next;
		struct __db **le_prev;
	} dblistlinks;

	/*
	 * Cursor queues.
	 *
	 * !!!
	 * Explicit representations of structures from queue.h.
	 * TAILQ_HEAD(__cq_fq, __dbc) free_queue;
	 * TAILQ_HEAD(__cq_aq, __dbc) active_queue;
	 * TAILQ_HEAD(__cq_jq, __dbc) join_queue;