diff options
Diffstat (limited to 'debian/htdig/htdig-3.2.0b6/db/bt_split.c')
| -rw-r--r-- | debian/htdig/htdig-3.2.0b6/db/bt_split.c | 1078 |
1 files changed, 1078 insertions, 0 deletions
diff --git a/debian/htdig/htdig-3.2.0b6/db/bt_split.c b/debian/htdig/htdig-3.2.0b6/db/bt_split.c new file mode 100644 index 00000000..5388cb00 --- /dev/null +++ b/debian/htdig/htdig-3.2.0b6/db/bt_split.c @@ -0,0 +1,1078 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996, 1997, 1998, 1999 + * Sleepycat Software. All rights reserved. + */ +/* + * Copyright (c) 1990, 1993, 1994, 1995, 1996 + * Keith Bostic. All rights reserved. + */ +/* + * Copyright (c) 1990, 1993, 1994, 1995 + * The Regents of the University of California. All rights reserved. + * + * 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. 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 "db_config.h" + +#ifndef lint +static const char sccsid[] = "@(#)bt_split.c 11.8 (Sleepycat) 10/21/99"; +#endif /* not lint */ + +#ifndef NO_SYSTEM_INCLUDES +#include <sys/types.h> + +#include <errno.h> +#include <limits.h> +#include <string.h> +#endif + +#include "db_int.h" +#include "db_page.h" +#include "db_shash.h" +#include "lock.h" +#include "btree.h" + +#ifdef DEBUG +#include "WordMonitor.h" +#endif /* DEBUG */ + +static int CDB___bam_broot __P((DBC *, PAGE *, PAGE *, PAGE *)); +static int CDB___bam_page __P((DBC *, EPG *, EPG *)); +static int CDB___bam_pinsert __P((DBC *, EPG *, PAGE *, PAGE *, int)); +static int CDB___bam_psplit __P((DBC *, EPG *, PAGE *, PAGE *, db_indx_t *)); +static int CDB___bam_root __P((DBC *, EPG *)); +static int CDB___ram_root __P((DBC *, PAGE *, PAGE *, PAGE *)); + +/* + * CDB___bam_split -- + * Split a page. + * + * PUBLIC: int CDB___bam_split __P((DBC *, void *)); + */ +int +CDB___bam_split(dbc, arg) + DBC *dbc; + void *arg; +{ + BTREE *t; + BTREE_CURSOR *cp; + DB *dbp; + enum { UP, DOWN } dir; + db_pgno_t root_pgno; + int exact, level, ret; + + dbp = dbc->dbp; + cp = dbc->internal; + root_pgno = ((BTREE *)dbp->bt_internal)->bt_root; + + /* + * The locking protocol we use to avoid deadlock to acquire locks by + * walking down the tree, but we do it as lazily as possible, locking + * the root only as a last resort. We expect all stack pages to have + * been discarded before we're called; we discard all short-term locks. + * + * When CDB___bam_split is first called, we know that a leaf page was too + * full for an insert. We don't know what leaf page it was, but we + * have the key/recno that caused the problem. We call XX_search to + * reacquire the leaf page, but this time get both the leaf page and + * its parent, locked. We then split the leaf page and see if the new + * internal key will fit into the parent page. If it will, we're done. + * + * If it won't, we discard our current locks and repeat the process, + * only this time acquiring the parent page and its parent, locked. + * This process repeats until we succeed in the split, splitting the + * root page as the final resort. The entire process then repeats, + * as necessary, until we split a leaf page. + * + * XXX + * A traditional method of speeding this up is to maintain a stack of + * the pages traversed in the original search. You can detect if the + * stack is correct by storing the page's LSN when it was searched and + * comparing that LSN with the current one when it's locked during the + * split. This would be an easy change for this code, but I have no + * numbers that indicate it's worthwhile. + */ + t = dbp->bt_internal; + for (dir = UP, level = LEAFLEVEL;; dir == UP ? ++level : --level) { + /* + * Acquire a page and its parent, locked. + */ + if ((ret = (dbp->type == DB_BTREE ? + CDB___bam_search(dbc, arg, S_WRPAIR, level, NULL, &exact) : + CDB___bam_rsearch(dbc, + (db_recno_t *)arg, S_WRPAIR, level, &exact))) != 0) + return (ret); + + /* + * Split the page if it still needs it (it's possible another + * thread of control has already split the page). If we are + * guaranteed that two items will fit on the page, the split + * is no longer necessary. + */ + if (t->bt_ovflsize * 2 <= + (db_indx_t)P_FREESPACE(cp->csp[0].page)) { + CDB___bam_stkrel(dbc, 1); + return (0); + } + ret = cp->csp[0].page->pgno == root_pgno ? + CDB___bam_root(dbc, &cp->csp[0]) : + CDB___bam_page(dbc, &cp->csp[-1], &cp->csp[0]); + BT_STK_CLR(cp); + + switch (ret) { + case 0: + /* Once we've split the leaf page, we're done. */ + if (level == LEAFLEVEL) + return (0); + + /* Switch directions. */ + if (dir == UP) + dir = DOWN; + break; + case DB_NEEDSPLIT: + /* + * It's possible to fail to split repeatedly, as other + * threads may be modifying the tree, or the page usage + * is sufficiently bad that we don't get enough space + * the first time. + */ + if (dir == DOWN) + dir = UP; + break; + default: + return (ret); + } + } + /* NOTREACHED */ +} + +/* + * CDB___bam_root -- + * Split the root page of a btree. + */ +static int +CDB___bam_root(dbc, cp) + DBC *dbc; + EPG *cp; +{ + DB *dbp; + PAGE *lp, *rp; + db_indx_t split; + int ret; + + dbp = dbc->dbp; + + /* Yeah, right. */ + if (cp->page->level >= MAXBTREELEVEL) { + ret = ENOSPC; + goto err; + } + + /* Create new left and right pages for the split. */ + lp = rp = NULL; + if ((ret = CDB___db_new(dbc, TYPE(cp->page), &lp)) != 0 || + (ret = CDB___db_new(dbc, TYPE(cp->page), &rp)) != 0) + goto err; + P_INIT(lp, dbp->pgsize, lp->pgno, + PGNO_INVALID, ISINTERNAL(cp->page) ? PGNO_INVALID : rp->pgno, + cp->page->level, TYPE(cp->page)); + P_INIT(rp, dbp->pgsize, rp->pgno, + ISINTERNAL(cp->page) ? PGNO_INVALID : lp->pgno, PGNO_INVALID, + cp->page->level, TYPE(cp->page)); + + /* Split the page. */ + if ((ret = CDB___bam_psplit(dbc, cp, lp, rp, &split)) != 0) + goto err; + + /* Log the change. */ + if (DB_LOGGING(dbc)) { + DBT __a; + DB_LSN __lsn; + memset(&__a, 0, sizeof(__a)); + __a.data = cp->page; + __a.size = dbp->pgsize; + ZERO_LSN(__lsn); + if ((ret = CDB___bam_split_log(dbp->dbenv, dbc->txn, + &LSN(cp->page), 0, dbp->log_fileid, PGNO(lp), &LSN(lp), + PGNO(rp), &LSN(rp), (u_int32_t)NUM_ENT(lp), 0, &__lsn, + &__a)) != 0) + goto err; + LSN(lp) = LSN(rp) = LSN(cp->page); + } + + /* Clean up the new root page. */ + if ((ret = (dbp->type == DB_RECNO ? + CDB___ram_root(dbc, cp->page, lp, rp) : + CDB___bam_broot(dbc, cp->page, lp, rp))) != 0) + goto err; + + /* Adjust any cursors. Do it last so we don't have to undo it. */ + CDB___bam_ca_split(dbp, cp->page->pgno, lp->pgno, rp->pgno, split, 1); + + /* Success -- write the real pages back to the store. */ + (void)CDB_memp_fput(dbp->mpf, cp->page, DB_MPOOL_DIRTY); + (void)__TLPUT(dbc, cp->lock); + (void)CDB_memp_fput(dbp->mpf, lp, DB_MPOOL_DIRTY); + (void)CDB_memp_fput(dbp->mpf, rp, DB_MPOOL_DIRTY); + + return (0); + +err: if (lp != NULL) + (void)CDB___db_free(dbc, lp); + if (rp != NULL) + (void)CDB___db_free(dbc, rp); + (void)CDB_memp_fput(dbp->mpf, cp->page, 0); + (void)__TLPUT(dbc, cp->lock); + return (ret); +} + +/* + * CDB___bam_page -- + * Split the non-root page of a btree. + */ +static int +CDB___bam_page(dbc, pp, cp) + DBC *dbc; + EPG *pp, *cp; +{ + DB *dbp; + DB_LOCK tplock; + DB_LSN save_lsn; + PAGE *lp, *rp, *alloc_rp, *tp; + db_indx_t split; + int ret, t_ret; + + dbp = dbc->dbp; + alloc_rp = lp = rp = tp = NULL; + tplock.off = LOCK_INVALID; + ret = -1; + + /* + * Create a new right page for the split, and fill in everything + * except its LSN and page number. + * + * We malloc space for both the left and right pages, so we don't get + * a new page from the underlying buffer pool until we know the split + * is going to succeed. The reason is that we can't release locks + * acquired during the get-a-new-page process because metadata page + * locks can't be discarded on failure since we may have modified the + * free list. So, if you assume that we're holding a write lock on the + * leaf page which ran out of space and started this split (e.g., we + * have already written records to the page, or we retrieved a record + * from it with the DB_RMW flag set), failing in a split with both a + * leaf page locked and the metadata page locked can potentially lock + * up the tree badly, because we've violated the rule of always locking + * down the tree, and never up. + */ + if ((ret = CDB___os_malloc(dbp->pgsize, NULL, &rp)) != 0) + goto err; + P_INIT(rp, dbp->pgsize, 0, + ISINTERNAL(cp->page) ? PGNO_INVALID : PGNO(cp->page), + ISINTERNAL(cp->page) ? PGNO_INVALID : NEXT_PGNO(cp->page), + cp->page->level, TYPE(cp->page)); + + /* + * Create new left page for the split, and fill in everything + * except its LSN and next-page page number. + */ + if ((ret = CDB___os_malloc(dbp->pgsize, NULL, &lp)) != 0) + goto err; + P_INIT(lp, dbp->pgsize, PGNO(cp->page), + ISINTERNAL(cp->page) ? PGNO_INVALID : PREV_PGNO(cp->page), + ISINTERNAL(cp->page) ? PGNO_INVALID : 0, + cp->page->level, TYPE(cp->page)); + + /* + * Split right. + * + * Only the indices are sorted on the page, i.e., the key/data pairs + * aren't, so it's simpler to copy the data from the split page onto + * two new pages instead of copying half the data to a new right page + * and compacting the left page in place. Since the left page can't + * change, we swap the original and the allocated left page after the + * split. + */ + if ((ret = CDB___bam_psplit(dbc, cp, lp, rp, &split)) != 0) + goto err; + + /* + * Test to see if we are going to be able to insert the new pages into + * the parent page. The interesting failure here is that the parent + * page can't hold the new keys, and has to be split in turn, in which + * case we want to release all the locks we can. + */ + if ((ret = CDB___bam_pinsert(dbc, pp, lp, rp, 1)) != 0) + goto err; + + /* + * Fix up the previous pointer of any leaf page following the split + * page. + * + * There's interesting deadlock situations here as we try to write-lock + * a page that's not in our direct ancestry. Consider a cursor walking + * backward through the leaf pages, that has our following page locked, + * and is waiting on a lock for the page we're splitting. In that case + * we're going to deadlock here . It's probably OK, stepping backward + * through the tree isn't a common operation. + */ + if (ISLEAF(cp->page) && NEXT_PGNO(cp->page) != PGNO_INVALID) { + if ((ret = CDB___db_lget(dbc, + 0, NEXT_PGNO(cp->page), DB_LOCK_WRITE, 0, &tplock)) != 0) + goto err; + if ((ret = + CDB_memp_fget(dbp->mpf, &NEXT_PGNO(cp->page), 0, &tp)) != 0) + goto err; + } + + /* + * We've got everything locked down we need, and we know the split + * is going to succeed. Go and get the additional page we'll need. + */ + if ((ret = CDB___db_new(dbc, TYPE(cp->page), &alloc_rp)) != 0) + goto err; + + /* + * Fix up the page numbers we didn't have before. We have to do this + * before calling CDB___bam_pinsert because it may copy a page number onto + * the parent page and it takes the page number from its page argument. + */ + PGNO(rp) = NEXT_PGNO(lp) = PGNO(alloc_rp); + + /* Actually update the parent page. */ + if ((ret = CDB___bam_pinsert(dbc, pp, lp, rp, 0)) != 0) + goto err; + + /* Log the change. */ + if (DB_LOGGING(dbc)) { + DBT __a; + DB_LSN __lsn; + memset(&__a, 0, sizeof(__a)); + __a.data = cp->page; + __a.size = dbp->pgsize; + if (tp == NULL) + ZERO_LSN(__lsn); + if ((ret = CDB___bam_split_log(dbp->dbenv, dbc->txn, + &LSN(cp->page), 0, dbp->log_fileid, PGNO(cp->page), + &LSN(cp->page), PGNO(alloc_rp), &LSN(alloc_rp), + (u_int32_t)NUM_ENT(lp), + tp == NULL ? 0 : PGNO(tp), + tp == NULL ? &__lsn : &LSN(tp), &__a)) != 0) + goto err; + + /* Update the LSNs for all involved pages. */ + LSN(alloc_rp) = LSN(lp) = LSN(rp) = LSN(cp->page); + if (tp != NULL) + LSN(tp) = LSN(cp->page); + } + + /* + * Copy the left and right pages into place. There are two paths + * through here. Either we are logging and we set the LSNs in the + * logging path. However, if we are not logging, then we do not + * have valid LSNs on lp or rp. The correct LSNs to use are the + * ones on the page we got from CDB___db_new or the one that was + * originally on cp->page. In both cases, we save the LSN from the + * real database page (not a malloc'd one) and reapply it after we + * do the copy. + */ + save_lsn = alloc_rp->lsn; + memcpy(alloc_rp, rp, LOFFSET(rp)); + memcpy((u_int8_t *)alloc_rp + HOFFSET(rp), + (u_int8_t *)rp + HOFFSET(rp), dbp->pgsize - HOFFSET(rp)); + alloc_rp->lsn = save_lsn; + + save_lsn = cp->page->lsn; + memcpy(cp->page, lp, LOFFSET(lp)); + memcpy((u_int8_t *)cp->page + HOFFSET(lp), + (u_int8_t *)lp + HOFFSET(lp), dbp->pgsize - HOFFSET(lp)); + cp->page->lsn = save_lsn; + + /* Fix up the next-page link. */ + if (tp != NULL) + PREV_PGNO(tp) = PGNO(rp); + + /* Adjust any cursors. Do it last so we don't have to undo it. */ + CDB___bam_ca_split(dbp, PGNO(cp->page), PGNO(cp->page), PGNO(rp), split, 0); + + CDB___os_free(lp, dbp->pgsize); + CDB___os_free(rp, dbp->pgsize); + + /* + * Success -- write the real pages back to the store. As we never + * acquired any sort of lock on the new page, we release it before + * releasing locks on the pages that reference it. We're finished + * modifying the page so it's not really necessary, but it's neater. + */ + if ((t_ret = + CDB_memp_fput(dbp->mpf, alloc_rp, DB_MPOOL_DIRTY)) != 0 && ret == 0) + ret = t_ret; + if ((t_ret = + CDB_memp_fput(dbp->mpf, pp->page, DB_MPOOL_DIRTY)) != 0 && ret == 0) + ret = t_ret; + (void)__TLPUT(dbc, pp->lock); + if ((t_ret = + CDB_memp_fput(dbp->mpf, cp->page, DB_MPOOL_DIRTY)) != 0 && ret == 0) + ret = t_ret; + (void)__TLPUT(dbc, cp->lock); + if (tp != NULL) { + if ((t_ret = + CDB_memp_fput(dbp->mpf, tp, DB_MPOOL_DIRTY)) != 0 && ret == 0) + ret = t_ret; + (void)__TLPUT(dbc, tplock); + } + return (ret); + +err: if (lp != NULL) + CDB___os_free(lp, dbp->pgsize); + if (rp != NULL) + CDB___os_free(rp, dbp->pgsize); + if (alloc_rp != NULL) + (void)CDB___db_free(dbc, alloc_rp); + + if (tp != NULL) + (void)CDB_memp_fput(dbp->mpf, tp, 0); + if (tplock.off != LOCK_INVALID) + /* We never updated the next page, we can release it. */ + (void)__LPUT(dbc, tplock); + + (void)CDB_memp_fput(dbp->mpf, pp->page, 0); + if (ret == DB_NEEDSPLIT) + (void)__LPUT(dbc, pp->lock); + else + (void)__TLPUT(dbc, pp->lock); + + (void)CDB_memp_fput(dbp->mpf, cp->page, 0); + if (ret == DB_NEEDSPLIT) + (void)__LPUT(dbc, cp->lock); + else + (void)__TLPUT(dbc, cp->lock); + + return (ret); +} + +/* + * CDB___bam_broot -- + * Fix up the btree root page after it has been split. + */ +static int +CDB___bam_broot(dbc, rootp, lp, rp) + DBC *dbc; + PAGE *rootp, *lp, *rp; +{ + BINTERNAL bi, *child_bi; + BKEYDATA *child_bk; + DB *dbp; + DBT hdr, data; + db_pgno_t root_pgno; + int ret; + + dbp = dbc->dbp; + + /* + * If the root page was a leaf page, change it into an internal page. + * We copy the key we split on (but not the key's data, in the case of + * a leaf page) to the new root page. + */ + root_pgno = ((BTREE *)dbp->bt_internal)->bt_root; + P_INIT(rootp, dbp->pgsize, + root_pgno, PGNO_INVALID, PGNO_INVALID, lp->level + 1, P_IBTREE); +#ifdef DEBUG + word_monitor_set(WORD_MONITOR_LEVEL, LEVEL(rootp)); +#endif /* DEBUG */ + + memset(&data, 0, sizeof(data)); + memset(&hdr, 0, sizeof(hdr)); + + /* + * The btree comparison code guarantees that the left-most key on any + * level of the tree is never used, so it doesn't need to be filled in. + */ + memset(&bi, 0, sizeof(bi)); + bi.len = 0; + B_TSET(bi.type, B_KEYDATA, 0); + bi.pgno = lp->pgno; + if (F_ISSET(dbp, DB_BT_RECNUM)) { + bi.nrecs = CDB___bam_total(lp); + RE_NREC_SET(rootp, bi.nrecs); + } + hdr.data = &bi; + hdr.size = SSZA(BINTERNAL, data); + if ((ret = + CDB___db_pitem(dbc, rootp, 0, BINTERNAL_SIZE(0), &hdr, NULL)) != 0) + return (ret); + + switch (TYPE(rp)) { + case P_IBTREE: + /* Copy the first key of the child page onto the root page. */ + child_bi = GET_BINTERNAL(rp, 0); + + bi.len = child_bi->len; + B_TSET(bi.type, child_bi->type, 0); + bi.pgno = rp->pgno; + if (F_ISSET(dbp, DB_BT_RECNUM)) { + bi.nrecs = CDB___bam_total(rp); + RE_NREC_ADJ(rootp, bi.nrecs); + } + hdr.data = &bi; + hdr.size = SSZA(BINTERNAL, data); + data.data = child_bi->data; + data.size = child_bi->len; + if ((ret = CDB___db_pitem(dbc, rootp, 1, + BINTERNAL_SIZE(child_bi->len), &hdr, &data)) != 0) + return (ret); + + /* Increment the overflow ref count. */ + if (B_TYPE(child_bi->type) == B_OVERFLOW) + if ((ret = CDB___db_ovref(dbc, + ((BOVERFLOW *)(child_bi->data))->pgno, 1)) != 0) + return (ret); + break; + case P_LBTREE: + /* Copy the first key of the child page onto the root page. */ + child_bk = GET_BKEYDATA(rp, 0); + switch (B_TYPE(child_bk->type)) { + case B_KEYDATA: + bi.len = child_bk->len; + B_TSET(bi.type, child_bk->type, 0); + bi.pgno = rp->pgno; + if (F_ISSET(dbp, DB_BT_RECNUM)) { + bi.nrecs = CDB___bam_total(rp); + RE_NREC_ADJ(rootp, bi.nrecs); + } + hdr.data = &bi; + hdr.size = SSZA(BINTERNAL, data); + data.data = child_bk->data; + data.size = child_bk->len; + if ((ret = CDB___db_pitem(dbc, rootp, 1, + BINTERNAL_SIZE(child_bk->len), &hdr, &data)) != 0) + return (ret); + break; + case B_DUPLICATE: + case B_OVERFLOW: + bi.len = BOVERFLOW_SIZE; + B_TSET(bi.type, child_bk->type, 0); + bi.pgno = rp->pgno; + if (F_ISSET(dbp, DB_BT_RECNUM)) { + bi.nrecs = CDB___bam_total(rp); + RE_NREC_ADJ(rootp, bi.nrecs); + } + hdr.data = &bi; + hdr.size = SSZA(BINTERNAL, data); + data.data = child_bk; + data.size = BOVERFLOW_SIZE; + if ((ret = CDB___db_pitem(dbc, rootp, 1, + BINTERNAL_SIZE(BOVERFLOW_SIZE), &hdr, &data)) != 0) + return (ret); + + /* Increment the overflow ref count. */ + if (B_TYPE(child_bk->type) == B_OVERFLOW) + if ((ret = CDB___db_ovref(dbc, + ((BOVERFLOW *)child_bk)->pgno, 1)) != 0) + return (ret); + break; + default: + return (CDB___db_pgfmt(dbp, rp->pgno)); + } + break; + default: + return (CDB___db_pgfmt(dbp, rp->pgno)); + } + return (0); +} + +/* + * CDB___ram_root -- + * Fix up the recno root page after it has been split. + */ +static int +CDB___ram_root(dbc, rootp, lp, rp) + DBC *dbc; + PAGE *rootp, *lp, *rp; +{ + DB *dbp; + DBT hdr; + RINTERNAL ri; + db_pgno_t root_pgno; + int ret; + + dbp = dbc->dbp; + root_pgno = ((BTREE *)dbp->bt_internal)->bt_root; + + /* Initialize the page. */ + P_INIT(rootp, dbp->pgsize, + root_pgno, PGNO_INVALID, PGNO_INVALID, lp->level + 1, P_IRECNO); + + /* Initialize the header. */ + memset(&hdr, 0, sizeof(hdr)); + hdr.data = &ri; + hdr.size = RINTERNAL_SIZE; + + /* Insert the left and right keys, set the header information. */ + ri.pgno = lp->pgno; + ri.nrecs = CDB___bam_total(lp); + if ((ret = CDB___db_pitem(dbc, rootp, 0, RINTERNAL_SIZE, &hdr, NULL)) != 0) + return (ret); + RE_NREC_SET(rootp, ri.nrecs); + ri.pgno = rp->pgno; + ri.nrecs = CDB___bam_total(rp); + if ((ret = CDB___db_pitem(dbc, rootp, 1, RINTERNAL_SIZE, &hdr, NULL)) != 0) + return (ret); + RE_NREC_ADJ(rootp, ri.nrecs); + return (0); +} + +/* + * CDB___bam_pinsert -- + * Insert a new key into a parent page, completing the split. + */ +static int +CDB___bam_pinsert(dbc, parent, lchild, rchild, space_check) + DBC *dbc; + EPG *parent; + PAGE *lchild, *rchild; + int space_check; +{ + BINTERNAL bi, *child_bi; + BKEYDATA *child_bk, *tmp_bk; + BTREE *t; + DB *dbp; + DBT a, b, hdr, data; + PAGE *ppage; + RINTERNAL ri; + db_indx_t off; + db_recno_t nrecs; + u_int32_t n, nbytes, nksize; + int ret; + + dbp = dbc->dbp; + t = dbp->bt_internal; + ppage = parent->page; + + /* If handling record numbers, count records split to the right page. */ + nrecs = !space_check && + (dbp->type == DB_RECNO || F_ISSET(dbp, DB_BT_RECNUM)) ? + CDB___bam_total(rchild) : 0; + + /* + * Now we insert the new page's first key into the parent page, which + * completes the split. The parent points to a PAGE and a page index + * offset, where the new key goes ONE AFTER the index, because we split + * to the right. + * + * XXX + * Some btree algorithms replace the key for the old page as well as + * the new page. We don't, as there's no reason to believe that the + * first key on the old page is any better than the key we have, and, + * in the case of a key being placed at index 0 causing the split, the + * key is unavailable. + */ + off = parent->indx + O_INDX; + + /* + * Calculate the space needed on the parent page. + * + * Prefix trees: space hack used when inserting into BINTERNAL pages. + * Retain only what's needed to distinguish between the new entry and + * the LAST entry on the page to its left. If the keys compare equal, + * retain the entire key. We ignore overflow keys, and the entire key + * must be retained for the next-to-leftmost key on the leftmost page + * of each level, or the search will fail. Applicable ONLY to internal + * pages that have leaf pages as children. Further reduction of the + * key between pairs of internal pages loses too much information. + */ + switch (TYPE(rchild)) { + case P_IBTREE: + child_bi = GET_BINTERNAL(rchild, 0); + nbytes = BINTERNAL_PSIZE(child_bi->len); + + if (P_FREESPACE(ppage) < nbytes) + return (DB_NEEDSPLIT); + if (space_check) + return (0); + + /* Add a new record for the right page. */ + memset(&bi, 0, sizeof(bi)); + bi.len = child_bi->len; + B_TSET(bi.type, child_bi->type, 0); + bi.pgno = rchild->pgno; + bi.nrecs = nrecs; + memset(&hdr, 0, sizeof(hdr)); + hdr.data = &bi; + hdr.size = SSZA(BINTERNAL, data); + memset(&data, 0, sizeof(data)); + data.data = child_bi->data; + data.size = child_bi->len; + if ((ret = CDB___db_pitem(dbc, ppage, off, + BINTERNAL_SIZE(child_bi->len), &hdr, &data)) != 0) + return (ret); + + /* Increment the overflow ref count. */ + if (B_TYPE(child_bi->type) == B_OVERFLOW) + if ((ret = CDB___db_ovref(dbc, + ((BOVERFLOW *)(child_bi->data))->pgno, 1)) != 0) + return (ret); + break; + case P_LBTREE: + child_bk = GET_BKEYDATA(rchild, 0); + switch (B_TYPE(child_bk->type)) { + case B_KEYDATA: + nbytes = BINTERNAL_PSIZE(child_bk->len); + nksize = child_bk->len; + if (t->bt_prefix == NULL) + goto noprefix; + if (ppage->prev_pgno == PGNO_INVALID && off <= 1) + goto noprefix; + tmp_bk = GET_BKEYDATA(lchild, NUM_ENT(lchild) - P_INDX); + if (B_TYPE(tmp_bk->type) != B_KEYDATA) + goto noprefix; + memset(&a, 0, sizeof(a)); + a.size = tmp_bk->len; + a.data = tmp_bk->data; + memset(&b, 0, sizeof(b)); + b.size = child_bk->len; + b.data = child_bk->data; + nksize = t->bt_prefix(&a, &b); + if ((n = BINTERNAL_PSIZE(nksize)) < nbytes) + nbytes = n; + else +noprefix: nksize = child_bk->len; + + if (P_FREESPACE(ppage) < nbytes) + return (DB_NEEDSPLIT); + if (space_check) + return (0); + + memset(&bi, 0, sizeof(bi)); + bi.len = nksize; + B_TSET(bi.type, child_bk->type, 0); + bi.pgno = rchild->pgno; + bi.nrecs = nrecs; + memset(&hdr, 0, sizeof(hdr)); + hdr.data = &bi; + hdr.size = SSZA(BINTERNAL, data); + memset(&data, 0, sizeof(data)); + data.data = child_bk->data; + data.size = nksize; + if ((ret = CDB___db_pitem(dbc, ppage, off, + BINTERNAL_SIZE(nksize), &hdr, &data)) != 0) + return (ret); + break; + case B_DUPLICATE: + case B_OVERFLOW: + nbytes = BINTERNAL_PSIZE(BOVERFLOW_SIZE); + + if (P_FREESPACE(ppage) < nbytes) + return (DB_NEEDSPLIT); + if (space_check) + return (0); + + memset(&bi, 0, sizeof(bi)); + bi.len = BOVERFLOW_SIZE; + B_TSET(bi.type, child_bk->type, 0); + bi.pgno = rchild->pgno; + bi.nrecs = nrecs; + memset(&hdr, 0, sizeof(hdr)); + hdr.data = &bi; + hdr.size = SSZA(BINTERNAL, data); + memset(&data, 0, sizeof(data)); + data.data = child_bk; + data.size = BOVERFLOW_SIZE; + if ((ret = CDB___db_pitem(dbc, ppage, off, + BINTERNAL_SIZE(BOVERFLOW_SIZE), &hdr, &data)) != 0) + return (ret); + + /* Increment the overflow ref count. */ + if (B_TYPE(child_bk->type) == B_OVERFLOW) + if ((ret = CDB___db_ovref(dbc, + ((BOVERFLOW *)child_bk)->pgno, 1)) != 0) + return (ret); + break; + default: + return (CDB___db_pgfmt(dbp, rchild->pgno)); + } + break; + case P_IRECNO: + case P_LRECNO: + nbytes = RINTERNAL_PSIZE; + + if (P_FREESPACE(ppage) < nbytes) + return (DB_NEEDSPLIT); + if (space_check) + return (0); + + /* Add a new record for the right page. */ + memset(&hdr, 0, sizeof(hdr)); + hdr.data = &ri; + hdr.size = RINTERNAL_SIZE; + ri.pgno = rchild->pgno; + ri.nrecs = nrecs; + if ((ret = CDB___db_pitem(dbc, + ppage, off, RINTERNAL_SIZE, &hdr, NULL)) != 0) + return (ret); + break; + default: + return (CDB___db_pgfmt(dbp, rchild->pgno)); + } + + /* Adjust the parent page's left page record count. */ + if (dbp->type == DB_RECNO || F_ISSET(dbp, DB_BT_RECNUM)) { + /* Log the change. */ + if (DB_LOGGING(dbc) && + (ret = CDB___bam_cadjust_log(dbp->dbenv, + dbc->txn, &LSN(ppage), 0, dbp->log_fileid, + PGNO(ppage), &LSN(ppage), (u_int32_t)parent->indx, + -(int32_t)nrecs, (int32_t)0)) != 0) + return (ret); + + /* Update the left page count. */ + if (dbp->type == DB_RECNO) + GET_RINTERNAL(ppage, parent->indx)->nrecs -= nrecs; + else + GET_BINTERNAL(ppage, parent->indx)->nrecs -= nrecs; + } + + return (0); +} + +/* + * CDB___bam_psplit -- + * Do the real work of splitting the page. + */ +static int +CDB___bam_psplit(dbc, cp, lp, rp, splitret) + DBC *dbc; + EPG *cp; + PAGE *lp, *rp; + db_indx_t *splitret; +{ + DB *dbp; + PAGE *pp; + db_indx_t half, nbytes, off, splitp, top; + int adjust, cnt, isbigkey, ret; + + dbp = dbc->dbp; + pp = cp->page; + adjust = TYPE(pp) == P_LBTREE ? P_INDX : O_INDX; + + /* + * If we're splitting the first (last) page on a level because we're + * inserting (appending) a key to it, it's likely that the data is + * sorted. Moving a single item to the new page is less work and can + * push the fill factor higher than normal. If we're wrong it's not + * a big deal, we'll just do the split the right way next time. + */ + off = 0; + if (NEXT_PGNO(pp) == PGNO_INVALID && + ((ISINTERNAL(pp) && cp->indx == NUM_ENT(cp->page) - 1) || + (!ISINTERNAL(pp) && cp->indx == NUM_ENT(cp->page)))) + off = NUM_ENT(cp->page) - adjust; + else if (PREV_PGNO(pp) == PGNO_INVALID && cp->indx == 0) + off = adjust; + + if (off != 0) + goto sort; + + /* + * Split the data to the left and right pages. Try not to split on + * an overflow key. (Overflow keys on internal pages will slow down + * searches.) Refuse to split in the middle of a set of duplicates. + * + * First, find the optimum place to split. + * + * It's possible to try and split past the last record on the page if + * there's a very large record at the end of the page. Make sure this + * doesn't happen by bounding the check at the next-to-last entry on + * the page. + * + * Note, we try and split half the data present on the page. This is + * because another process may have already split the page and left + * it half empty. We don't try and skip the split -- we don't know + * how much space we're going to need on the page, and we may need up + * to half the page for a big item, so there's no easy test to decide + * if we need to split or not. Besides, if two threads are inserting + * data into the same place in the database, we're probably going to + * need more space soon anyway. + */ + top = NUM_ENT(pp) - adjust; + half = (dbp->pgsize - HOFFSET(pp)) / 2; + for (nbytes = 0, off = 0; off < top && nbytes < half; ++off) + switch (TYPE(pp)) { + case P_IBTREE: + if (B_TYPE(GET_BINTERNAL(pp, off)->type) == B_KEYDATA) + nbytes += + BINTERNAL_SIZE(GET_BINTERNAL(pp, off)->len); + else + nbytes += BINTERNAL_SIZE(BOVERFLOW_SIZE); + break; + case P_LBTREE: + if (B_TYPE(GET_BKEYDATA(pp, off)->type) == B_KEYDATA) + nbytes += + BKEYDATA_SIZE(GET_BKEYDATA(pp, off)->len); + else + nbytes += BOVERFLOW_SIZE; + + ++off; + if (B_TYPE(GET_BKEYDATA(pp, off)->type) == B_KEYDATA) + nbytes += + BKEYDATA_SIZE(GET_BKEYDATA(pp, off)->len); + else + nbytes += BOVERFLOW_SIZE; + break; + case P_IRECNO: + nbytes += RINTERNAL_SIZE; + break; + case P_LRECNO: + nbytes += BKEYDATA_SIZE(GET_BKEYDATA(pp, off)->len); + break; + default: + return (CDB___db_pgfmt(dbp, pp->pgno)); + } +sort: splitp = off; + + /* + * Splitp is either at or just past the optimum split point. If + * it's a big key, try and find something close by that's not. + */ + if (TYPE(pp) == P_IBTREE) + isbigkey = B_TYPE(GET_BINTERNAL(pp, off)->type) != B_KEYDATA; + else if (TYPE(pp) == P_LBTREE) + isbigkey = B_TYPE(GET_BKEYDATA(pp, off)->type) != B_KEYDATA; + else + isbigkey = 0; + if (isbigkey) + for (cnt = 1; cnt <= 3; ++cnt) { + off = splitp + cnt * adjust; + if (off < (db_indx_t)NUM_ENT(pp) && + ((TYPE(pp) == P_IBTREE && + B_TYPE(GET_BINTERNAL(pp,off)->type) == B_KEYDATA) || + B_TYPE(GET_BKEYDATA(pp, off)->type) == B_KEYDATA)) { + splitp = off; + break; + } + if (splitp <= (db_indx_t)(cnt * adjust)) + continue; + off = splitp - cnt * adjust; + if (TYPE(pp) == P_IBTREE ? + B_TYPE(GET_BINTERNAL(pp, off)->type) == B_KEYDATA : + B_TYPE(GET_BKEYDATA(pp, off)->type) == B_KEYDATA) { + splitp = off; + break; + } + } + + /* + * We can't split in the middle a set of duplicates. We know that + * no duplicate set can take up more than about 25% of the page, + * because that's the point where we push it off onto a duplicate + * page set. So, this loop can't be unbounded. + */ + if (F_ISSET(dbp, DB_AM_DUP) && TYPE(pp) == P_LBTREE && + pp->inp[splitp] == pp->inp[splitp - adjust]) + for (cnt = 1;; ++cnt) { + off = splitp + cnt * adjust; + if (off < NUM_ENT(pp) && + pp->inp[splitp] != pp->inp[off]) { + splitp = off; + break; + } + if (splitp <= (db_indx_t)(cnt * adjust)) + continue; + off = splitp - cnt * adjust; + if (pp->inp[splitp] != pp->inp[off]) { + splitp = off + adjust; + break; + } + } + + + /* We're going to split at splitp. */ + if ((ret = CDB___bam_copy(dbp, pp, lp, 0, splitp)) != 0) + return (ret); + if ((ret = CDB___bam_copy(dbp, pp, rp, splitp, NUM_ENT(pp))) != 0) + return (ret); + + *splitret = splitp; + return (0); +} + +/* + * CDB___bam_copy -- + * Copy a set of records from one page to another. + * + * PUBLIC: int CDB___bam_copy __P((DB *, PAGE *, PAGE *, u_int32_t, u_int32_t)); + */ +int +CDB___bam_copy(dbp, pp, cp, nxt, stop) + DB *dbp; + PAGE *pp, *cp; + u_int32_t nxt, stop; +{ + db_indx_t nbytes, off; + + /* + * Copy the rest of the data to the right page. Nxt is the next + * offset placed on the target page. + */ + for (off = 0; nxt < stop; ++nxt, ++NUM_ENT(cp), ++off) { + switch (TYPE(pp)) { + case P_IBTREE: + if (B_TYPE(GET_BINTERNAL(pp, nxt)->type) == B_KEYDATA) + nbytes = + BINTERNAL_SIZE(GET_BINTERNAL(pp, nxt)->len); + else + nbytes = BINTERNAL_SIZE(BOVERFLOW_SIZE); + break; + case P_LBTREE: + /* + * If we're on a key and it's a duplicate, just copy + * the offset. + */ + if (off != 0 && (nxt % P_INDX) == 0 && + pp->inp[nxt] == pp->inp[nxt - P_INDX]) { + cp->inp[off] = cp->inp[off - P_INDX]; + continue; + } + /* FALLTHROUGH */ + case P_LRECNO: + if (B_TYPE(GET_BKEYDATA(pp, nxt)->type) == B_KEYDATA) + nbytes = + BKEYDATA_SIZE(GET_BKEYDATA(pp, nxt)->len); + else + nbytes = BOVERFLOW_SIZE; + break; + case P_IRECNO: + nbytes = RINTERNAL_SIZE; + break; + default: + return (CDB___db_pgfmt(dbp, pp->pgno)); + } + cp->inp[off] = HOFFSET(cp) -= nbytes; + memcpy(P_ENTRY(cp, off), P_ENTRY(pp, nxt), nbytes); + } + return (0); +} |