From 09006ccec7928c9cf53bca6abe741e8d4d466c98 Mon Sep 17 00:00:00 2001 From: Howard Chu Date: Sun, 18 Sep 2011 10:38:08 -0700 Subject: [PATCH] API change, consistency check mdb_close() takes an env, not a txn. Also, add check for stale DB records (in case some other process wrote to the DB last). --- libraries/libmdb/mdb.c | 142 ++++++++++++++++++++++++++---------- libraries/libmdb/mdb.h | 25 ++++++- libraries/libmdb/mdb_stat.c | 2 +- libraries/libmdb/mtest.c | 2 +- libraries/libmdb/mtest2.c | 2 +- libraries/libmdb/mtest3.c | 2 +- libraries/libmdb/mtest4.c | 2 +- libraries/libmdb/mtest5.c | 2 +- 8 files changed, 132 insertions(+), 47 deletions(-) diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c index 8a877c7..9496914 100644 --- a/libraries/libmdb/mdb.c +++ b/libraries/libmdb/mdb.c @@ -691,9 +691,6 @@ typedef struct MDB_meta { /** Auxiliary DB info. * The information here is mostly static/read-only. There is * only a single copy of this record in the environment. - * The \b md_dirty flag is not read-only, but only a write - * transaction can ever update it, and only write transactions - * need to worry about it. */ typedef struct MDB_dbx { MDB_val md_name; /**< name of the database */ @@ -701,8 +698,6 @@ typedef struct MDB_dbx { MDB_cmp_func *md_dcmp; /**< function for comparing data items */ MDB_rel_func *md_rel; /**< user relocate function */ void *md_relctx; /**< user-provided context for md_rel */ - MDB_dbi md_parent; /**< parent DB of a sub-DB */ - unsigned int md_dirty; /**< TRUE if DB was written in this txn */ } MDB_dbx; /** A database transaction. @@ -728,6 +723,15 @@ struct MDB_txn { MDB_dbx *mt_dbxs; /** Array of MDB_db records for each known DB */ MDB_db *mt_dbs; +/** @defgroup mt_dbflag Transaction DB Flags + * @ingroup internal + * @{ + */ +#define DB_DIRTY 0x01 /**< DB was written in this txn */ +#define DB_STALE 0x02 /**< DB record is older than txnID */ +/** @} */ + /** Array of flags for each DB */ + unsigned char *mt_dbflags; /** Number of DB records in use. This number only ever increments; * we don't decrement it when individual DB handles are closed. */ @@ -767,6 +771,8 @@ struct MDB_cursor { MDB_db *mc_db; /** The database auxiliary record for this cursor */ MDB_dbx *mc_dbx; + /** The @ref mt_dbflag for this database */ + unsigned char *mc_dbflag; unsigned short mc_snum; /**< number of pushed pages */ unsigned short mc_top; /**< index of top page, mc_snum-1 */ /** @defgroup mdb_cursor Cursor Flags @@ -794,6 +800,8 @@ typedef struct MDB_xcursor { MDB_db mx_db; /** The auxiliary DB record for this Dup DB */ MDB_dbx mx_dbx; + /** The @ref mt_dbflag for this Dup DB */ + unsigned char mx_dbflag; } MDB_xcursor; /** A set of pages freed by an earlier transaction. */ @@ -830,6 +838,7 @@ struct MDB_env { pgno_t me_maxpg; /**< me_mapsize / me_psize */ unsigned int me_psize; /**< size of a page, from #GET_PAGESIZE */ unsigned int me_db_toggle; /**< which DB table is current */ + txnid_t me_wtxnid; /**< ID of last txn we committed */ MDB_dbx *me_dbxs; /**< array of static DB info */ MDB_db *me_dbs[2]; /**< two arrays of MDB_db info */ MDB_oldpages *me_pghead; /**< list of old page records */ @@ -1167,6 +1176,7 @@ static inline int mdb_txn_renew0(MDB_txn *txn) { MDB_env *env = txn->mt_env; + char mt_dbflag = 0; if (txn->mt_flags & MDB_TXN_RDONLY) { MDB_reader *r = pthread_getspecific(env->me_txkey); @@ -1191,14 +1201,22 @@ mdb_txn_renew0(MDB_txn *txn) r = &env->me_txns->mti_readers[i]; pthread_setspecific(env->me_txkey, r); } - txn->mt_txnid = env->me_txns->mti_txnid; txn->mt_toggle = env->me_txns->mti_me_toggle; + txn->mt_txnid = env->me_txns->mti_txnid; + /* This happens if a different process was the + * last writer to the DB. + */ + if (env->me_wtxnid < txn->mt_txnid) + mt_dbflag = DB_STALE; r->mr_txnid = txn->mt_txnid; txn->mt_u.reader = r; } else { LOCK_MUTEX_W(env); - txn->mt_txnid = env->me_txns->mti_txnid+1; + txn->mt_txnid = env->me_txns->mti_txnid; + if (env->me_wtxnid < txn->mt_txnid) + mt_dbflag = DB_STALE; + txn->mt_txnid++; txn->mt_toggle = env->me_txns->mti_me_toggle; txn->mt_u.dirty_list = env->me_dirty_list; txn->mt_u.dirty_list[0].mid = 0; @@ -1218,6 +1236,8 @@ mdb_txn_renew0(MDB_txn *txn) (txn->mt_numdbs - 2) * sizeof(MDB_db)); LAZY_RWLOCK_UNLOCK(&env->me_dblock); + memset(txn->mt_dbflags, mt_dbflag, env->me_numdbs); + return MDB_SUCCESS; } @@ -1253,7 +1273,8 @@ mdb_txn_begin(MDB_env *env, unsigned int flags, MDB_txn **ret) DPUTS("environment had fatal error, must shutdown!"); return MDB_PANIC; } - if ((txn = calloc(1, sizeof(MDB_txn) + env->me_maxdbs * sizeof(MDB_db))) == NULL) { + if ((txn = calloc(1, sizeof(MDB_txn) + + env->me_maxdbs * (sizeof(MDB_db)+1))) == NULL) { DPRINTF("calloc: %s", strerror(ErrCode())); return ENOMEM; } @@ -1261,6 +1282,7 @@ mdb_txn_begin(MDB_env *env, unsigned int flags, MDB_txn **ret) if (flags & MDB_RDONLY) { txn->mt_flags |= MDB_TXN_RDONLY; } + txn->mt_dbflags = (unsigned char *)(txn->mt_dbs + env->me_maxdbs); txn->mt_env = env; rc = mdb_txn_renew0(txn); @@ -1289,7 +1311,6 @@ mdb_txn_reset0(MDB_txn *txn) } else { MDB_oldpages *mop; MDB_page *dp; - MDB_dbi dbi; unsigned int i; /* return all dirty pages to dpage list */ @@ -1310,8 +1331,6 @@ mdb_txn_reset0(MDB_txn *txn) } env->me_txn = NULL; - for (dbi=2; dbime_numdbs; dbi++) - env->me_dbxs[dbi].md_dirty = 0; /* The writer mutex was locked in mdb_txn_begin. */ UNLOCK_MUTEX_W(env); } @@ -1362,6 +1381,23 @@ mdb_txn_commit(MDB_txn *txn) env = txn->mt_env; if (F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)) { + if (txn->mt_numdbs > env->me_numdbs) { + /* update the DB tables */ + int toggle = !env->me_db_toggle; + MDB_db *ip, *jp; + MDB_dbi i; + + ip = &env->me_dbs[toggle][env->me_numdbs]; + jp = &txn->mt_dbs[env->me_numdbs]; + LAZY_RWLOCK_WRLOCK(&env->me_dblock); + for (i = env->me_numdbs; i < txn->mt_numdbs; i++) { + *ip++ = *jp++; + } + + env->me_db_toggle = toggle; + env->me_numdbs = txn->mt_numdbs; + LAZY_RWLOCK_UNLOCK(&env->me_dblock); + } mdb_txn_abort(txn); return MDB_SUCCESS; } @@ -1456,7 +1492,7 @@ mdb_txn_commit(MDB_txn *txn) mdb_cursor_init(&mc, txn, MAIN_DBI, NULL); for (i = 2; i < txn->mt_numdbs; i++) { - if (txn->mt_dbxs[i].md_dirty) { + if (txn->mt_dbflags[i] & DB_DIRTY) { data.mv_data = &txn->mt_dbs[i]; mdb_cursor_put(&mc, &txn->mt_dbxs[i].md_name, &data, 0); } @@ -1578,6 +1614,7 @@ mdb_txn_commit(MDB_txn *txn) } done: + env->me_wtxnid = txn->mt_txnid; env->me_txn = NULL; /* update the DB tables */ { @@ -1594,10 +1631,6 @@ done: ip++; jp++; } - for (i = 2; i < txn->mt_numdbs; i++) { - if (txn->mt_dbxs[i].md_dirty) - txn->mt_dbxs[i].md_dirty = 0; - } env->me_db_toggle = toggle; env->me_numdbs = txn->mt_numdbs; LAZY_RWLOCK_UNLOCK(&env->me_dblock); @@ -2825,16 +2858,32 @@ mdb_page_search(MDB_cursor *mc, MDB_val *key, int modify) DPRINTF("db %u root page %zu has flags 0x%X", mc->mc_dbi, root, mc->mc_pg[0]->mp_flags); - if (modify) { - /* For sub-databases, update main root first */ - if (mc->mc_dbi > MAIN_DBI && !mc->mc_dbx->md_dirty) { + /* For sub-databases, update main root first */ + if (mc->mc_dbi > MAIN_DBI) { + if ((*mc->mc_dbflag & DB_STALE) || + (modify && !(*mc->mc_dbflag & DB_DIRTY))) { MDB_cursor mc2; + unsigned char dbflag = 0; mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL); - rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 1); + rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, modify); if (rc) return rc; - mc->mc_dbx->md_dirty = 1; + if (*mc->mc_dbflag & DB_STALE) { + MDB_val data; + int exact = 0; + MDB_node *leaf = mdb_node_search(&mc2, + &mc->mc_dbx->md_name, &exact); + if (!exact) + return MDB_NOTFOUND; + mdb_node_read(mc->mc_txn, leaf, &data); + memcpy(mc->mc_db, data.mv_data, sizeof(MDB_db)); + } + if (modify) + dbflag = DB_DIRTY; + *mc->mc_dbflag = dbflag; } + } + if (modify) { if (!F_ISSET(mc->mc_pg[0]->mp_flags, P_DIRTY)) { if ((rc = mdb_page_touch(mc))) return rc; @@ -3475,13 +3524,13 @@ mdb_cursor_touch(MDB_cursor *mc) { int rc; - if (mc->mc_dbi > MAIN_DBI && !mc->mc_dbx->md_dirty) { + if (mc->mc_dbi > MAIN_DBI && !(*mc->mc_dbflag & DB_DIRTY)) { MDB_cursor mc2; mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL); rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 1); if (rc) return rc; - mc->mc_dbx->md_dirty = 1; + *mc->mc_dbflag = DB_DIRTY; } for (mc->mc_top = 0; mc->mc_top < mc->mc_snum; mc->mc_top++) { if (!F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY)) { @@ -3502,7 +3551,7 @@ int mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data, unsigned int flags) { - MDB_node *leaf; + MDB_node *leaf = NULL; MDB_val xdata, *rdata, dkey; MDB_page *fp; MDB_db dummy; @@ -3536,7 +3585,7 @@ mdb_cursor_put(MDB_cursor *mc, MDB_val *key, MDB_val *data, mdb_cursor_push(mc, np); mc->mc_db->md_root = np->mp_pgno; mc->mc_db->md_depth++; - mc->mc_dbx->md_dirty = 1; + *mc->mc_dbflag = DB_DIRTY; if ((mc->mc_db->md_flags & (MDB_DUPSORT|MDB_DUPFIXED)) == MDB_DUPFIXED) np->mp_flags |= P_LEAF2; @@ -4181,11 +4230,10 @@ mdb_xcursor_init0(MDB_cursor *mc) mx->mx_cursor.mc_db = &mx->mx_db; mx->mx_cursor.mc_dbx = &mx->mx_dbx; mx->mx_cursor.mc_dbi = mc->mc_dbi+1; - mx->mx_dbx.md_parent = mc->mc_dbi; + mx->mx_cursor.mc_dbflag = &mx->mx_dbflag; mx->mx_dbx.md_cmp = mc->mc_dbx->md_dcmp; mx->mx_dbx.md_dcmp = NULL; mx->mx_dbx.md_rel = mc->mc_dbx->md_rel; - mx->mx_dbx.md_dirty = 0; } /** Final setup of a sorted-dups cursor. @@ -4228,8 +4276,8 @@ mdb_xcursor_init1(MDB_cursor *mc, MDB_node *node) } DPRINTF("Sub-db %u for db %u root page %zu", mx->mx_cursor.mc_dbi, mc->mc_dbi, mx->mx_db.md_root); - if (F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY)) - mx->mx_dbx.md_dirty = 1; + mx->mx_dbflag = (F_ISSET(mc->mc_pg[mc->mc_top]->mp_flags, P_DIRTY)) ? + DB_DIRTY : 0; mx->mx_dbx.md_name.mv_data = NODEKEY(node); mx->mx_dbx.md_name.mv_size = node->mn_ksize; if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(size_t)) @@ -4244,6 +4292,7 @@ mdb_cursor_init(MDB_cursor *mc, MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx) mc->mc_txn = txn; mc->mc_db = &txn->mt_dbs[dbi]; mc->mc_dbx = &txn->mt_dbxs[dbi]; + mc->mc_dbflag = &txn->mt_dbflags[dbi]; mc->mc_snum = 0; mc->mc_flags = 0; if (txn->mt_dbs[dbi].md_flags & MDB_DUPSORT) { @@ -5152,7 +5201,7 @@ int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi) { MDB_val key, data; MDB_dbi i; - int rc, dirty = 0; + int rc, dbflag = 0; size_t len; if (txn->mt_dbxs[FREE_DBI].md_cmp == NULL) { @@ -5201,7 +5250,7 @@ int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi) dummy.md_flags = flags & 0xffff; mdb_cursor_init(&mc, txn, MAIN_DBI, NULL); rc = mdb_cursor_put(&mc, &key, &data, F_SUBDATA); - dirty = 1; + dbflag = DB_DIRTY; } /* OK, got info, add to table */ @@ -5209,8 +5258,7 @@ int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi) txn->mt_dbxs[txn->mt_numdbs].md_name.mv_data = strdup(name); txn->mt_dbxs[txn->mt_numdbs].md_name.mv_size = len; txn->mt_dbxs[txn->mt_numdbs].md_rel = NULL; - txn->mt_dbxs[txn->mt_numdbs].md_parent = MAIN_DBI; - txn->mt_dbxs[txn->mt_numdbs].md_dirty = dirty; + txn->mt_dbflags[txn->mt_numdbs] = dbflag; memcpy(&txn->mt_dbs[txn->mt_numdbs], data.mv_data, sizeof(MDB_db)); *dbi = txn->mt_numdbs; txn->mt_env->me_dbs[0][txn->mt_numdbs] = txn->mt_dbs[txn->mt_numdbs]; @@ -5230,17 +5278,35 @@ int mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *arg) return mdb_stat0(txn->mt_env, &txn->mt_dbs[dbi], arg); } -void mdb_close(MDB_txn *txn, MDB_dbi dbi) +void mdb_close(MDB_env *env, MDB_dbi dbi) { char *ptr; - if (dbi <= MAIN_DBI || dbi >= txn->mt_numdbs) + if (dbi <= MAIN_DBI || dbi >= env->me_numdbs) return; - ptr = txn->mt_dbxs[dbi].md_name.mv_data; - txn->mt_dbxs[dbi].md_name.mv_data = NULL; - txn->mt_dbxs[dbi].md_name.mv_size = 0; + ptr = env->me_dbxs[dbi].md_name.mv_data; + env->me_dbxs[dbi].md_name.mv_data = NULL; + env->me_dbxs[dbi].md_name.mv_size = 0; free(ptr); } +int mdb_drop(MDB_env *env, MDB_dbi dbi) +{ + MDB_txn *txn; + int rc; + + if (!env || !dbi || dbi >= env->me_numdbs) + return EINVAL; + + if (env->me_txn) + return EBUSY; + + rc = mdb_txn_begin(env, 0, &txn); + if (rc) + return rc; + + +} + int mdb_set_compare(MDB_txn *txn, MDB_dbi dbi, MDB_cmp_func *cmp) { if (txn == NULL || !dbi || dbi >= txn->mt_numdbs) diff --git a/libraries/libmdb/mdb.h b/libraries/libmdb/mdb.h index b99ece7..04293d4 100644 --- a/libraries/libmdb/mdb.h +++ b/libraries/libmdb/mdb.h @@ -592,15 +592,34 @@ int mdb_open(MDB_txn *txn, const char *name, unsigned int flags, MDB_dbi *dbi); int mdb_stat(MDB_txn *txn, MDB_dbi dbi, MDB_stat *stat); /** Close a database handle. - * @param[in] txn A transaction handle returned by #mdb_txn_begin() + * This call is not mutex protected. Handles should only be closed by + * a single thread, and only if no other threads are going to reference + * the database handle any further. + * @param[in] env An environment handle returned by #mdb_env_create() + * @param[in] dbi A database handle returned by #mdb_open() + */ +void mdb_close(MDB_env *env, MDB_dbi dbi); + + /** Delete a database and free all its pages. + * This function acquires its own write transaction to perform its + * work, so it must not be called if there is already an open write + * transaction in the environment. The database handle will also be + * closed as part of this operation. + * @param[in] env An environment handle returned by #mdb_env_create() * @param[in] dbi A database handle returned by #mdb_open() + * @return A non-zero error value on failure and 0 on success. Some possible + * errors are: + * */ -void mdb_close(MDB_txn *txn, MDB_dbi dbi); +int mdb_drop(MDB_env *env, MDB_dbi dbi); /** Set a custom key comparison function for a database. * The comparison function is called whenever it is necessary to compare a * key specified by the application with a key currently stored in the database. - * If no comparison function is specified, and no special key flags were specified + * If no comparison function is specified, and no speAGAINcial key flags were specified * with #mdb_open(), the keys are compared lexically, with shorter keys collating * before longer keys. * @warning This function must be called before any data access functions are used, diff --git a/libraries/libmdb/mdb_stat.c b/libraries/libmdb/mdb_stat.c index 4bcdb92..931ec61 100644 --- a/libraries/libmdb/mdb_stat.c +++ b/libraries/libmdb/mdb_stat.c @@ -56,7 +56,7 @@ int main(int argc,char * argv[]) printf("Leaf pages: %zu\n", mst.ms_leaf_pages); printf("Overflow pages: %zu\n", mst.ms_overflow_pages); printf("Entries: %zu\n", mst.ms_entries); - mdb_close(txn, dbi); + mdb_close(env, dbi); mdb_txn_abort(txn); mdb_env_close(env); diff --git a/libraries/libmdb/mtest.c b/libraries/libmdb/mtest.c index 8f2ecbf..89f0ac4 100644 --- a/libraries/libmdb/mtest.c +++ b/libraries/libmdb/mtest.c @@ -146,7 +146,7 @@ int main(int argc,char * argv[]) } #endif mdb_cursor_close(cursor); - mdb_close(txn, dbi); + mdb_close(env, dbi); mdb_txn_abort(txn); mdb_env_close(env); diff --git a/libraries/libmdb/mtest2.c b/libraries/libmdb/mtest2.c index 5aeb97d..17c1ecf 100644 --- a/libraries/libmdb/mtest2.c +++ b/libraries/libmdb/mtest2.c @@ -108,7 +108,7 @@ int main(int argc,char * argv[]) (int) data.mv_size, (char *) data.mv_data); } mdb_cursor_close(cursor); - mdb_close(txn, dbi); + mdb_close(env, dbi); mdb_txn_abort(txn); mdb_env_close(env); diff --git a/libraries/libmdb/mtest3.c b/libraries/libmdb/mtest3.c index 467a123..43e3481 100644 --- a/libraries/libmdb/mtest3.c +++ b/libraries/libmdb/mtest3.c @@ -118,7 +118,7 @@ int main(int argc,char * argv[]) (int) data.mv_size, (char *) data.mv_data); } mdb_cursor_close(cursor); - mdb_close(txn, dbi); + mdb_close(env, dbi); mdb_txn_abort(txn); mdb_env_close(env); diff --git a/libraries/libmdb/mtest4.c b/libraries/libmdb/mtest4.c index d3a7877..821055a 100644 --- a/libraries/libmdb/mtest4.c +++ b/libraries/libmdb/mtest4.c @@ -152,7 +152,7 @@ int main(int argc,char * argv[]) (int) data.mv_size, (char *) data.mv_data); } mdb_cursor_close(cursor); - mdb_close(txn, dbi); + mdb_close(env, dbi); mdb_txn_abort(txn); mdb_env_close(env); diff --git a/libraries/libmdb/mtest5.c b/libraries/libmdb/mtest5.c index 472b100..5fb6bb0 100644 --- a/libraries/libmdb/mtest5.c +++ b/libraries/libmdb/mtest5.c @@ -120,7 +120,7 @@ int main(int argc,char * argv[]) (int) data.mv_size, (char *) data.mv_data); } mdb_cursor_close(cursor); - mdb_close(txn, dbi); + mdb_close(env, dbi); mdb_txn_abort(txn); mdb_env_close(env);