/*- * See the file LICENSE for redistribution information. * * Copyright (c) 1996, 1997, 1998 * Sleepycat Software. All rights reserved. */ /* * Copyright (c) 1995, 1996 * The President and Fellows of Harvard University. All rights reserved. * * This code is derived from software contributed to Berkeley by * Margo Seltzer. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include "config.h" #ifndef lint static const char sccsid[] = "@(#)db_dispatch.c 10.20 (Sleepycat) 10/10/98"; #endif /* not lint */ #ifndef NO_SYSTEM_INCLUDES #include <sys/types.h> #include <errno.h> #include <shqueue.h> #include <stddef.h> #include <stdlib.h> #include <string.h> #endif #include "db_int.h" #include "db_page.h" #include "db_dispatch.h" #include "db_am.h" #include "common_ext.h" #include "log_auto.h" #include "txn.h" #include "txn_auto.h" /* * Data structures to manage the DB dispatch table. The dispatch table * is a dynamically allocated array of pointers to dispatch functions. * The dispatch_size is the number of entries possible in the current * dispatch table and the dispatch_valid is the number of valid entries * in the dispatch table. */ static int (**dispatch_table) __P((DB_LOG *, DBT *, DB_LSN *, int, void *)); static u_int32_t dispatch_size = 0; /* * __db_dispatch -- * * This is the transaction dispatch function used by the db access methods. * It is designed to handle the record format used by all the access * methods (the one automatically generated by the db_{h,log,read}.sh * scripts in the tools directory). An application using a different * recovery paradigm will supply a different dispatch function to txn_open. * * PUBLIC: int __db_dispatch __P((DB_LOG *, DBT *, DB_LSN *, int, void *)); */ int __db_dispatch(logp, db, lsnp, redo, info) DB_LOG *logp; /* The log file. */ DBT *db; /* The log record upon which to dispatch. */ DB_LSN *lsnp; /* The lsn of the record being dispatched. */ int redo; /* Redo this op (or undo it). */ void *info; { u_int32_t rectype, txnid; memcpy(&rectype, db->data, sizeof(rectype)); memcpy(&txnid, (u_int8_t *)db->data + sizeof(rectype), sizeof(txnid)); switch (redo) { case TXN_REDO: case TXN_UNDO: return ((dispatch_table[rectype])(logp, db, lsnp, redo, info)); case TXN_OPENFILES: if (rectype < DB_txn_BEGIN ) return ((dispatch_table[rectype])(logp, db, lsnp, redo, info)); break; case TXN_BACKWARD_ROLL: /* * Running full recovery in the backward pass. If we've * seen this txnid before and added to it our commit list, * then we do nothing during this pass. If we've never * seen it, then we call the appropriate recovery routine * in "abort mode". */ if (rectype == DB_log_register || rectype == DB_txn_ckp || (__db_txnlist_find(info, txnid) == DB_NOTFOUND && txnid != 0)) return ((dispatch_table[rectype])(logp, db, lsnp, TXN_UNDO, info)); break; case TXN_FORWARD_ROLL: /* * In the forward pass, if we haven't seen the transaction, * do nothing, else recovery it. */ if (rectype == DB_log_register || rectype == DB_txn_ckp || __db_txnlist_find(info, txnid) != DB_NOTFOUND) return ((dispatch_table[rectype])(logp, db, lsnp, TXN_REDO, info)); break; default: abort(); } return (0); } /* * __db_add_recovery -- * * PUBLIC: int __db_add_recovery __P((DB_ENV *, * PUBLIC: int (*)(DB_LOG *, DBT *, DB_LSN *, int, void *), u_int32_t)); */ int __db_add_recovery(dbenv, func, ndx) DB_ENV *dbenv; int (*func) __P((DB_LOG *, DBT *, DB_LSN *, int, void *)); u_int32_t ndx; { u_int32_t i; int ret; COMPQUIET(dbenv, NULL); /* !!!: not currently used. */ /* Check if we have to grow the table. */ if (ndx >= dispatch_size) { if ((ret = __os_realloc(&dispatch_table, (DB_user_BEGIN + dispatch_size) * sizeof(dispatch_table[0]))) != 0) return (ret); for (i = dispatch_size, dispatch_size += DB_user_BEGIN; i < dispatch_size; ++i) dispatch_table[i] = NULL; } dispatch_table[ndx] = func; return (0); } /* * __db_txnlist_init -- * Initialize transaction linked list. * * PUBLIC: int __db_txnlist_init __P((void *)); */ int __db_txnlist_init(retp) void *retp; { DB_TXNHEAD *headp; int ret; if ((ret = __os_malloc(sizeof(DB_TXNHEAD), NULL, &headp)) != 0) return (ret); LIST_INIT(&headp->head); headp->maxid = 0; headp->generation = 1; *(void **)retp = headp; return (0); } /* * __db_txnlist_add -- * Add an element to our transaction linked list. * * PUBLIC: int __db_txnlist_add __P((void *, u_int32_t)); */ int __db_txnlist_add(listp, txnid) void *listp; u_int32_t txnid; { DB_TXNHEAD *hp; DB_TXNLIST *elp; int ret; if ((ret = __os_malloc(sizeof(DB_TXNLIST), NULL, &elp)) != 0) return (ret); elp->txnid = txnid; hp = (DB_TXNHEAD *)listp; LIST_INSERT_HEAD(&hp->head, elp, links); if (txnid > hp->maxid) hp->maxid = txnid; elp->generation = hp->generation; return (0); } /* * __db_txnlist_find -- * Checks to see if a txnid with the current generation is in the * txnid list. * * PUBLIC: int __db_txnlist_find __P((void *, u_int32_t)); */ int __db_txnlist_find(listp, txnid) void *listp; u_int32_t txnid; { DB_TXNHEAD *hp; DB_TXNLIST *p; if ((hp = (DB_TXNHEAD *)listp) == NULL) return (DB_NOTFOUND); for (p = hp->head.lh_first; p != NULL; p = p->links.le_next) if (p->txnid == txnid && hp->generation == p->generation) return (0); return (DB_NOTFOUND); } /* * __db_txnlist_end -- * Discard transaction linked list. * * PUBLIC: void __db_txnlist_end __P((void *)); */ void __db_txnlist_end(listp) void *listp; { DB_TXNHEAD *hp; DB_TXNLIST *p; hp = (DB_TXNHEAD *)listp; while ((p = LIST_FIRST(&hp->head)) != LIST_END(&hp->head)) { LIST_REMOVE(p, links); __os_free(p, 0); } __os_free(listp, sizeof(DB_TXNHEAD)); } /* * __db_txnlist_gen -- * Change the current generation number. * * PUBLIC: void __db_txnlist_gen __P((void *, int)); */ void __db_txnlist_gen(listp, incr) void *listp; int incr; { DB_TXNHEAD *hp; /* * During recovery generation numbers keep track of how many "restart" * checkpoints we've seen. Restart checkpoints occur whenever we take * a checkpoint and there are no outstanding transactions. When that * happens, we can reset transaction IDs back to 1. It always happens * at recovery and it prevents us from exhausting the transaction IDs * name space. */ hp = (DB_TXNHEAD *)listp; hp->generation += incr; } #ifdef DEBUG /* * __db_txnlist_print -- * Print out the transaction list. * * PUBLIC: void __db_txnlist_print __P((void *)); */ void __db_txnlist_print(listp) void *listp; { DB_TXNHEAD *hp; DB_TXNLIST *p; hp = (DB_TXNHEAD *)listp; printf("Maxid: %lu Generation: %lu\n", (u_long)hp->maxid, (u_long)hp->generation); for (p = hp->head.lh_first; p != NULL; p = p->links.le_next) printf("TXNID: %lu(%lu)\n", (u_long)p->txnid, (u_long)p->generation); } #endif
