txn.h

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/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998, 1999, 2000
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: txn_8h-source.html,v 1.1 2008/06/08 10:24:49 sebdiaz Exp $
 */

#ifndef _TXN_H_
#define _TXN_H_

#include "xa.h"

struct __db_txnmgr;     typedef struct __db_txnmgr DB_TXNMGR;
struct __db_txnregion;  typedef struct __db_txnregion DB_TXNREGION;

/*
 * !!!
 * TXN_MINIMUM = (DB_LOCK_MAXID + 1) but this makes compilers complain.
 */
#define TXN_MINIMUM     0x80000000
#define TXN_INVALID     0xffffffff      /* Maximum number of txn ids. */
#define TXN_INVALID_ID  0               /* Invalid transaction ID. */

#define DEF_MAX_TXNS    20              /* Default max transactions. */

/* The structure allocated for every transaction. */
struct __db_txn {
        DB_TXNMGR       *mgrp;          /* Pointer to transaction manager. */
        DB_TXN          *parent;        /* Pointer to transaction's parent. */
        DB_LSN          last_lsn;       /* Lsn of last log write. */
        u_int32_t       txnid;          /* Unique transaction id. */
        roff_t          off;            /* Detail structure within region. */
        TAILQ_ENTRY(__db_txn) links;    /* Links transactions off manager. */
        TAILQ_HEAD(__kids, __db_txn) kids; /* Child transactions. */
        TAILQ_ENTRY(__db_txn) klinks;   /* Links child transactions. */

#define TXN_CHILDCOMMIT 0x01            /* Transaction that has committed. */
#define TXN_MALLOC      0x02            /* Structure allocated by TXN system. */
#define TXN_MUSTFLUSH   0x04            /* A child has committed. */
#define TXN_NOSYNC      0x08            /* Do not sync on prepare and commit. */
#define TXN_NOWAIT      0x10            /* Do not wait on locks. */
#define TXN_SYNC        0x20            /* Sync on prepare and commit. */
        u_int32_t       flags;
};

/*
 * Internal data maintained in shared memory for each transaction.
 */
typedef char DB_XID[XIDDATASIZE];

typedef struct __txn_detail {
        u_int32_t txnid;                /* current transaction id
                                           used to link free list also */
        DB_LSN  last_lsn;               /* last lsn written for this txn */
        DB_LSN  begin_lsn;              /* lsn of begin record */
        roff_t  parent;                 /* Offset of transaction's parent. */

#define TXN_UNALLOC             0
#define TXN_RUNNING             1
#define TXN_ABORTED             2
#define TXN_PREPARED            3
#define TXN_COMMITTED           4
        u_int32_t status;               /* status of the transaction */

        SH_TAILQ_ENTRY  links;          /* free/active list */

#define TXN_XA_ABORTED          1
#define TXN_XA_DEADLOCKED       2
#define TXN_XA_ENDED            3
#define TXN_XA_PREPARED         4
#define TXN_XA_STARTED          5
#define TXN_XA_SUSPENDED        6
        u_int32_t xa_status;            /* XA status */

        /*
         * XID (xid_t) structure: because these fields are logged, the
         * sizes have to be explicit.
         */
        DB_XID xid;                     /* XA global transaction id */
        u_int32_t bqual;                /* bqual_length from XID */
        u_int32_t gtrid;                /* gtrid_length from XID */
        int32_t format;                 /* XA format */
} TXN_DETAIL;

/*
 * DB_TXNMGR --
 *      The transaction manager encapsulates the transaction system.
 */
struct __db_txnmgr {
/*
 * These fields need to be protected for multi-threaded support.
 *
 * !!!
 * As this structure is allocated in per-process memory, the mutex may need
 * to be stored elsewhere on architectures unable to support mutexes in heap
 * memory, e.g., HP/UX 9.
 */
        MUTEX           *mutexp;        /* Lock list of active transactions
                                         * (including the content of each
                                         * TXN_DETAIL structure on the list).
                                         */
                                        /* List of active transactions. */
        TAILQ_HEAD(_chain, __db_txn)    txn_chain;

/* These fields are never updated after creation, and so not protected. */
        DB_ENV          *dbenv;         /* Environment. */
        REGINFO          reginfo;       /* Region information. */

        int (*recover)                  /* Recovery dispatch routine */
            __P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
};

/*
 * DB_TXNREGION --
 *      The primary transaction data structure in the shared memory region.
 */
struct __db_txnregion {
        u_int32_t       maxtxns;        /* maximum number of active TXNs */
        u_int32_t       last_txnid;     /* last transaction id given out */
        DB_LSN          pending_ckp;    /* last checkpoint did not finish */
        DB_LSN          last_ckp;       /* lsn of the last checkpoint */
        time_t          time_ckp;       /* time of last checkpoint */
        u_int32_t       logtype;        /* type of logging */
        u_int32_t       locktype;       /* lock type */
        u_int32_t       naborts;        /* number of aborted TXNs */
        u_int32_t       ncommits;       /* number of committed TXNs */
        u_int32_t       nbegins;        /* number of begun TXNs */
        u_int32_t       nactive;        /* number of active TXNs */
        u_int32_t       maxnactive;     /* maximum number of active TXNs */
                                        /* active TXN list */
        SH_TAILQ_HEAD(__active) active_txn;
};

/*
 * Make the region large enough to hold N transaction detail structures
 * plus some space to hold thread handles and the beginning of the shalloc
 * region.
 */
#define TXN_REGION_SIZE(N)                                              \
        (sizeof(DB_TXNREGION) + N * sizeof(TXN_DETAIL) + 1000)

/*
 * Log record types.
 */
#define TXN_COMMIT      1
#define TXN_PREPARE     2
#define TXN_CHECKPOINT  3

#include "txn_auto.h"
#include "txn_ext.h"

#include "xa_ext.h"
#endif /* !_TXN_H_ */

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