diff options
Diffstat (limited to 'innobase/btr/btr0pcur.c')
| -rw-r--r-- | innobase/btr/btr0pcur.c | 70 |
1 files changed, 52 insertions, 18 deletions
diff --git a/innobase/btr/btr0pcur.c b/innobase/btr/btr0pcur.c index 5e625553929..8ca3d41f7f9 100644 --- a/innobase/btr/btr0pcur.c +++ b/innobase/btr/btr0pcur.c @@ -62,8 +62,10 @@ btr_pcur_free_for_mysql( /****************************************************************** The position of the cursor is stored by taking an initial segment of the record the cursor is positioned on, before, or after, and copying it to the -cursor data structure. NOTE that the page where the cursor is positioned -must not be empty! */ +cursor data structure, or just setting a flag if the cursor id before the +first in an EMPTY tree, or after the last in an EMPTY tree. NOTE that the +page where the cursor is positioned must not be empty if the index tree is +not totally empty! */ void btr_pcur_store_position( @@ -93,9 +95,21 @@ btr_pcur_store_position( ut_a(cursor->latch_mode != BTR_NO_LATCHES); if (page_get_n_recs(page) == 0) { + /* It must be an empty index tree */ - /* Cannot store position! */ - btr_pcur_close(cursor); + ut_a(btr_page_get_next(page, mtr) == FIL_NULL + && btr_page_get_prev(page, mtr) == FIL_NULL); + + if (rec == page_get_supremum_rec(page)) { + + cursor->rel_pos = BTR_PCUR_AFTER_LAST_IN_TREE; + cursor->old_stored = BTR_PCUR_OLD_STORED; + + return; + } + + cursor->rel_pos = BTR_PCUR_BEFORE_FIRST_IN_TREE; + cursor->old_stored = BTR_PCUR_OLD_STORED; return; } @@ -140,13 +154,15 @@ btr_pcur_copy_stored_position( ut_memcpy((byte*)pcur_receive, (byte*)pcur_donate, sizeof(btr_pcur_t)); - pcur_receive->old_rec_buf = mem_alloc(pcur_donate->buf_size); + if (pcur_donate->old_rec_buf) { + + pcur_receive->old_rec_buf = mem_alloc(pcur_donate->buf_size); - ut_memcpy(pcur_receive->old_rec_buf, pcur_donate->old_rec_buf, + ut_memcpy(pcur_receive->old_rec_buf, pcur_donate->old_rec_buf, pcur_donate->buf_size); - pcur_receive->old_rec = pcur_receive->old_rec_buf + pcur_receive->old_rec = pcur_receive->old_rec_buf + (pcur_donate->old_rec - pcur_donate->old_rec_buf); - + } } /****************************************************************** @@ -158,7 +174,9 @@ to the last record LESS OR EQUAL to the stored record; the last record LESS than the user record which was the successor of the page infimum; (3) cursor was positioned on the page supremum: restores to the first record -GREATER than the user record which was the predecessor of the supremum. */ +GREATER than the user record which was the predecessor of the supremum. +(4) cursor was positioned before the first or after the last in an empty tree: +restores to before first or after the last in the tree. */ ibool btr_pcur_restore_position( @@ -177,17 +195,33 @@ btr_pcur_restore_position( dtuple_t* tuple; ulint mode; ulint old_mode; + ibool from_left; mem_heap_t* heap; - ut_a((cursor->pos_state == BTR_PCUR_WAS_POSITIONED) - || (cursor->pos_state == BTR_PCUR_IS_POSITIONED)); + ut_a(cursor->pos_state == BTR_PCUR_WAS_POSITIONED + || cursor->pos_state == BTR_PCUR_IS_POSITIONED); ut_a(cursor->old_stored == BTR_PCUR_OLD_STORED); + + if (cursor->rel_pos == BTR_PCUR_AFTER_LAST_IN_TREE + || cursor->rel_pos == BTR_PCUR_BEFORE_FIRST_IN_TREE) { + + if (cursor->rel_pos == BTR_PCUR_BEFORE_FIRST_IN_TREE) { + from_left = TRUE; + } else { + from_left = FALSE; + } + + btr_cur_open_at_index_side(from_left, + btr_pcur_get_btr_cur(cursor)->index, latch_mode, + btr_pcur_get_btr_cur(cursor), mtr); + return(FALSE); + } + ut_a(cursor->old_rec); page = btr_cur_get_page(btr_pcur_get_btr_cur(cursor)); - if ((latch_mode == BTR_SEARCH_LEAF) - || (latch_mode == BTR_MODIFY_LEAF)) { + if (latch_mode == BTR_SEARCH_LEAF || latch_mode == BTR_MODIFY_LEAF) { /* Try optimistic restoration */ if (buf_page_optimistic_get(latch_mode, page, @@ -242,16 +276,15 @@ btr_pcur_restore_position( /* Restore the old search mode */ cursor->search_mode = old_mode; - if ((cursor->rel_pos == BTR_PCUR_ON) - && btr_pcur_is_on_user_rec(cursor, mtr) - && (0 == cmp_dtuple_rec(tuple, btr_pcur_get_rec(cursor)))) { + if (cursor->rel_pos == BTR_PCUR_ON + && btr_pcur_is_on_user_rec(cursor, mtr) + && 0 == cmp_dtuple_rec(tuple, btr_pcur_get_rec(cursor))) { /* We have to store the NEW value for the modify clock, since the cursor can now be on a different page! */ cursor->modify_clock = buf_frame_get_modify_clock( - buf_frame_align( - btr_pcur_get_rec(cursor))); + buf_frame_align(btr_pcur_get_rec(cursor))); mem_heap_free(heap); return(TRUE); @@ -366,6 +399,7 @@ btr_pcur_move_backward_from_page( latch_mode2 = BTR_MODIFY_PREV; } else { + latch_mode2 = 0; /* To eliminate compiler warning */ ut_error; } |