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author | Ulrich Drepper <drepper@redhat.com> | 1999-06-13 13:36:34 +0000 |
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committer | Ulrich Drepper <drepper@redhat.com> | 1999-06-13 13:36:34 +0000 |
commit | ec239360d13518a13f572b635d036c7d10028010 (patch) | |
tree | bdb5111363f45d2107849c2456b575d72779174c /db2/db/db_join.c | |
parent | fc3703521650a9b6db910a50c4fc0f410496e134 (diff) | |
download | glibc-ec239360d13518a13f572b635d036c7d10028010.tar.gz glibc-ec239360d13518a13f572b635d036c7d10028010.tar.xz glibc-ec239360d13518a13f572b635d036c7d10028010.zip |
Update.
* db2/Makefile (distribute): Remove files which do not exist anymore.
Diffstat (limited to 'db2/db/db_join.c')
-rw-r--r-- | db2/db/db_join.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/db2/db/db_join.c b/db2/db/db_join.c new file mode 100644 index 0000000000..a4051c20b0 --- /dev/null +++ b/db2/db/db_join.c @@ -0,0 +1,271 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1998 + * Sleepycat Software. All rights reserved. + */ + +#include "config.h" + +#ifndef lint +static const char sccsid[] = "@(#)db_join.c 10.10 (Sleepycat) 10/9/98"; +#endif /* not lint */ + +#ifndef NO_SYSTEM_INCLUDES +#include <sys/types.h> + +#include <errno.h> +#include <string.h> +#endif + +#include "db_int.h" +#include "db_page.h" +#include "db_join.h" +#include "db_am.h" +#include "common_ext.h" + +static int __db_join_close __P((DBC *)); +static int __db_join_del __P((DBC *, u_int32_t)); +static int __db_join_get __P((DBC *, DBT *, DBT *, u_int32_t)); +static int __db_join_put __P((DBC *, DBT *, DBT *, u_int32_t)); + +/* + * This is the duplicate-assisted join functionality. Right now we're + * going to write it such that we return one item at a time, although + * I think we may need to optimize it to return them all at once. + * It should be easier to get it working this way, and I believe that + * changing it should be fairly straightforward. + * + * XXX + * Right now we do not maintain the number of duplicates so we do + * not optimize the join. If the caller does, then best performance + * will be achieved by putting the cursor with the smallest cardinality + * first. + * + * The first cursor moves sequentially through the duplicate set while + * the others search explicitly for the duplicate in question. + * + */ + +/* + * __db_join -- + * This is the interface to the duplicate-assisted join functionality. + * In the same way that cursors mark a position in a database, a cursor + * can mark a position in a join. While most cursors are created by the + * cursor method of a DB, join cursors are created through an explicit + * call to DB->join. + * + * The curslist is an array of existing, intialized cursors and primary + * is the DB of the primary file. The data item that joins all the + * cursors in the curslist is used as the key into the primary and that + * key and data are returned. When no more items are left in the join + * set, the c_next operation off the join cursor will return DB_NOTFOUND. + * + * PUBLIC: int __db_join __P((DB *, DBC **, u_int32_t, DBC **)); + */ +int +__db_join(primary, curslist, flags, dbcp) + DB *primary; + DBC **curslist, **dbcp; + u_int32_t flags; +{ + DBC *dbc; + JOIN_CURSOR *jc; + int i, ret; + + DB_PANIC_CHECK(primary); + + if ((ret = __db_joinchk(primary, flags)) != 0) + return (ret); + + if (curslist == NULL || curslist[0] == NULL) + return (EINVAL); + + dbc = NULL; + jc = NULL; + + if ((ret = __os_calloc(1, sizeof(DBC), &dbc)) != 0) + goto err; + + if ((ret = __os_calloc(1, sizeof(JOIN_CURSOR), &jc)) != 0) + goto err; + + if ((ret = __os_malloc(256, NULL, &jc->j_key.data)) != 0) + goto err; + jc->j_key.ulen = 256; + F_SET(&jc->j_key, DB_DBT_USERMEM); + + for (jc->j_curslist = curslist; + *jc->j_curslist != NULL; jc->j_curslist++) + ; + if ((ret = __os_calloc((jc->j_curslist - curslist + 1), + sizeof(DBC *), &jc->j_curslist)) != 0) + goto err; + for (i = 0; curslist[i] != NULL; i++) { + if (i != 0) + F_SET(curslist[i], DBC_KEYSET); + jc->j_curslist[i] = curslist[i]; + } + + dbc->c_close = __db_join_close; + dbc->c_del = __db_join_del; + dbc->c_get = __db_join_get; + dbc->c_put = __db_join_put; + dbc->internal = jc; + dbc->dbp = primary; + jc->j_init = 1; + jc->j_primary = primary; + + *dbcp = dbc; + + return (0); + +err: if (jc != NULL) { + if (jc->j_curslist != NULL) + __os_free(jc->j_curslist, + (jc->j_curslist - curslist + 1) * sizeof(DBC *)); + __os_free(jc, sizeof(JOIN_CURSOR)); + } + if (dbc != NULL) + __os_free(dbc, sizeof(DBC)); + return (ret); +} + +static int +__db_join_put(dbc, key, data, flags) + DBC *dbc; + DBT *key; + DBT *data; + u_int32_t flags; +{ + DB_PANIC_CHECK(dbc->dbp); + + COMPQUIET(key, NULL); + COMPQUIET(data, NULL); + COMPQUIET(flags, 0); + return (EINVAL); +} + +static int +__db_join_del(dbc, flags) + DBC *dbc; + u_int32_t flags; +{ + DB_PANIC_CHECK(dbc->dbp); + + COMPQUIET(flags, 0); + return (EINVAL); +} + +static int +__db_join_get(dbc, key, data, flags) + DBC *dbc; + DBT *key, *data; + u_int32_t flags; +{ + DB *dbp; + DBC **cpp; + JOIN_CURSOR *jc; + int ret; + u_int32_t operation; + + dbp = dbc->dbp; + + DB_PANIC_CHECK(dbp); + + operation = LF_ISSET(DB_OPFLAGS_MASK); + if (operation != 0 && operation != DB_JOIN_ITEM) + return (__db_ferr(dbp->dbenv, "DBcursor->c_get", 0)); + + LF_CLR(DB_OPFLAGS_MASK); + if ((ret = + __db_fchk(dbp->dbenv, "DBcursor->c_get", flags, DB_RMW)) != 0) + return (ret); + + jc = (JOIN_CURSOR *)dbc->internal; +retry: + ret = jc->j_curslist[0]->c_get(jc->j_curslist[0], + &jc->j_key, key, jc->j_init ? DB_CURRENT : DB_NEXT_DUP); + + if (ret == ENOMEM) { + jc->j_key.ulen <<= 1; + if ((ret = __os_realloc(&jc->j_key.data, jc->j_key.ulen)) != 0) + return (ret); + goto retry; + } + if (ret != 0) + return (ret); + + jc->j_init = 0; + do { + /* + * We have the first element; now look for it in the + * other cursors. + */ + for (cpp = jc->j_curslist + 1; *cpp != NULL; cpp++) { +retry2: if ((ret = ((*cpp)->c_get)(*cpp, + &jc->j_key, key, DB_GET_BOTH)) == DB_NOTFOUND) + break; + if (ret == ENOMEM) { + jc->j_key.ulen <<= 1; + if ((ret = __os_realloc(&jc->j_key.data, + jc->j_key.ulen)) != 0) + return (ret); + goto retry2; + } + if (F_ISSET(*cpp, DBC_KEYSET)) { + F_CLR(*cpp, DBC_KEYSET); + F_SET(*cpp, DBC_CONTINUE); + } + } + + /* + * If we got out of here with ret != 0, then we failed to + * find the duplicate in one of the files, so we go on to + * the next item in the outermost relation. If ret was + * equal to 0, then we've got something to return. + */ + if (ret == 0) + break; + } while ((ret = jc->j_curslist[0]->c_get(jc->j_curslist[0], + &jc->j_key, key, DB_NEXT_DUP)) == 0); + + /* + * If ret != 0 here, we've exhausted the first file. Otherwise, + * key and data are set and we need to do the lookup on the + * primary. + */ + if (ret != 0) + return (ret); + + if (operation == DB_JOIN_ITEM) + return (0); + else + return ((jc->j_primary->get)(jc->j_primary, + jc->j_curslist[0]->txn, key, data, 0)); +} + +static int +__db_join_close(dbc) + DBC *dbc; +{ + JOIN_CURSOR *jc; + int i; + + DB_PANIC_CHECK(dbc->dbp); + + jc = (JOIN_CURSOR *)dbc->internal; + + /* + * Clear the optimization flag in the cursors. + */ + for (i = 0; jc->j_curslist[i] != NULL; i++) + F_CLR(jc->j_curslist[i], DBC_CONTINUE | DBC_KEYSET); + + __os_free(jc->j_curslist, 0); + __os_free(jc->j_key.data, jc->j_key.ulen); + __os_free(jc, sizeof(JOIN_CURSOR)); + __os_free(dbc, sizeof(DBC)); + + return (0); +} |