diff options
Diffstat (limited to 'src/third_party/wiredtiger/src/btree/bt_curprev.c')
| -rw-r--r-- | src/third_party/wiredtiger/src/btree/bt_curprev.c | 52 |
1 files changed, 30 insertions, 22 deletions
diff --git a/src/third_party/wiredtiger/src/btree/bt_curprev.c b/src/third_party/wiredtiger/src/btree/bt_curprev.c index 1e4b1daa090..a083ec4016e 100644 --- a/src/third_party/wiredtiger/src/btree/bt_curprev.c +++ b/src/third_party/wiredtiger/src/btree/bt_curprev.c @@ -1,5 +1,5 @@ /*- - * Copyright (c) 2014-2015 MongoDB, Inc. + * Copyright (c) 2014-2016 MongoDB, Inc. * Copyright (c) 2008-2014 WiredTiger, Inc. * All rights reserved. * @@ -139,10 +139,20 @@ __cursor_fix_append_prev(WT_CURSOR_BTREE *cbt, bool newpage) if ((cbt->ins = WT_SKIP_LAST(cbt->ins_head)) == NULL) return (WT_NOTFOUND); } else { + /* Move to the previous record in the append list, if any. */ + if (cbt->ins != NULL && + cbt->recno <= WT_INSERT_RECNO(cbt->ins)) + WT_RET(__cursor_skip_prev(cbt)); + /* * Handle the special case of leading implicit records, that is, - * there aren't any records in the tree not on the append list, - * and the first record on the append list isn't record 1. + * there aren't any records in the page not on the append list, + * and the append list's first record isn't the first record on + * the page. (Although implemented as a test of the page values, + * this is really a test for a tree where the first inserted + * record wasn't record 1, any other page with only an append + * list will have a first page record number matching the first + * record in the append list.) * * The "right" place to handle this is probably in our caller. * The high-level cursor-previous routine would: @@ -156,27 +166,26 @@ __cursor_fix_append_prev(WT_CURSOR_BTREE *cbt, bool newpage) * into our caller. Anyway, if this code breaks for any reason, * that's the way I'd go. * - * If we're not pointing to a WT_INSERT entry, or we can't find - * a WT_INSERT record that precedes our record name-space, check - * if there are any records on the page. If there aren't, then - * we're in the magic zone, keep going until we get to a record - * number of 1. + * If we're not pointing to a WT_INSERT entry (we didn't find a + * WT_INSERT record preceding our record name-space), check if + * we've reached the beginning of this page, a possibility if a + * page had a large number of items appended, and then split. + * If not, check if there are any records on the page. If there + * aren't, then we're in the magic zone, keep going until we get + * to a record number matching the first record on the page. */ - if (cbt->ins != NULL && - cbt->recno <= WT_INSERT_RECNO(cbt->ins)) - WT_RET(__cursor_skip_prev(cbt)); if (cbt->ins == NULL && - (cbt->recno == 1 || __col_fix_last_recno(page) != 0)) + (cbt->recno == page->pg_fix_recno || + __col_fix_last_recno(page) != 0)) return (WT_NOTFOUND); } /* - * This code looks different from the cursor-next code. The append - * list appears on the last page of the tree and contains the last - * records in the tree. If we're iterating through the tree, starting - * at the last record in the tree, by definition we're starting a new - * iteration and we set the record number to the last record found in - * the tree. Otherwise, decrement the record. + * This code looks different from the cursor-next code. The append list + * may be preceded by other rows. If we're iterating through the tree, + * starting at the last record in the tree, by definition we're starting + * a new iteration and we set the record number to the last record found + * on the page. Otherwise, decrement the record. */ if (newpage) __cursor_set_recno(cbt, WT_INSERT_RECNO(cbt->ins)); @@ -556,12 +565,11 @@ __wt_btcur_prev(WT_CURSOR_BTREE *cbt, bool truncating) */ for (newpage = false;; newpage = true) { page = cbt->ref == NULL ? NULL : cbt->ref->page; - WT_ASSERT(session, page == NULL || !WT_PAGE_IS_INTERNAL(page)); /* - * The last page in a column-store has appended entries. - * We handle it separately from the usual cursor code: - * it's only that one page and it's in a simple format. + * Column-store pages may have appended entries. Handle it + * separately from the usual cursor code, it's in a simple + * format. */ if (newpage && page != NULL && page->type != WT_PAGE_ROW_LEAF && (cbt->ins_head = WT_COL_APPEND(page)) != NULL) |