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MDEV-34458: Remove more traces of BTR_MODIFY_PREV

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In commit 2f6df9374806665db0764c74187a384b562b150a
we fixed an observed case of the bug by removing
some code related to the no longer needed
BTR_MODIFY_PREV mode.

In commit 73ad436e16c3ac022a2f1c477eac0e9a7e702707
an alternative fix was applied that also fixes the
BTR_SEARCH_PREV case.

Let us clean up some implicit references to BTR_MODIFY_PREV
that were missed in 2f6df9374806665db0764c74187a384b562b150a.

btr_pcur_move_backward_from_page(): Assume that the latch mode was
BTR_SEARCH_LEAF.

btr_pcur_move_to_prev(): Assert that the latch mode is BTR_SEARCH_LEAF.
This function is mostly invoked in row0sel.cc for read operations,
as well as in row0merge.cc for reading from the clustered index.
All callers indeed use a cursor in the BTR_SEARCH_LEAF mode.
This commit is contained in:
Marko Mäkelä 2024-07-29 14:13:30 +03:00
parent 88711ee509
commit 7ead48a72b
2 changed files with 8 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
storage/innobase/btr/btr0cur.cc
View File

@ -1301,11 +1301,9 @@ dberr_t btr_cur_t::search_leaf(const dtuple_t *tuple, page_cur_mode_t mode,
} }
switch (latch_mode) { switch (latch_mode) {
case BTR_SEARCH_PREV: case BTR_SEARCH_PREV: /* btr_pcur_move_to_prev() */
static_assert(BTR_SEARCH_PREV & BTR_SEARCH_LEAF, "");
ut_ad(!latch_by_caller); ut_ad(!latch_by_caller);
ut_ad(rw_latch == ut_ad(rw_latch == RW_S_LATCH);
rw_lock_type_t(latch_mode & (RW_X_LATCH | RW_S_LATCH)));
/* latch also siblings from left to right */ /* latch also siblings from left to right */
if (page_has_prev(block->page.frame) && if (page_has_prev(block->page.frame) &&
@ -1479,7 +1477,7 @@ release_tree:
rw_latch= RW_X_LATCH; rw_latch= RW_X_LATCH;
break; break;
case BTR_SEARCH_PREV: /* btr_pcur_move_to_prev() */ case BTR_SEARCH_PREV: /* btr_pcur_move_to_prev() */
ut_ad(rw_latch == RW_S_LATCH || rw_latch == RW_X_LATCH); ut_ad(rw_latch == RW_S_LATCH);
if (!not_first_access) if (!not_first_access)
buf_read_ahead_linear(page_id, zip_size); buf_read_ahead_linear(page_id, zip_size);

17
storage/innobase/btr/btr0pcur.cc
View File

@ -336,10 +336,9 @@ btr_pcur_t::restore_position(btr_latch_mode restore_latch_mode, mtr_t *mtr)
ut_a(old_n_core_fields <= index->n_core_fields); ut_a(old_n_core_fields <= index->n_core_fields);
ut_a(old_n_fields); ut_a(old_n_fields);
static_assert(BTR_SEARCH_PREV == (4 | BTR_SEARCH_LEAF), ""); static_assert(int{BTR_SEARCH_PREV} == (4 | BTR_SEARCH_LEAF), "");
switch (restore_latch_mode | 4) { if ((restore_latch_mode | 4) == BTR_SEARCH_PREV) {
case BTR_SEARCH_PREV:
/* Try optimistic restoration. */ /* Try optimistic restoration. */
if (btr_pcur_optimistic_latch_leaves(this, &restore_latch_mode, if (btr_pcur_optimistic_latch_leaves(this, &restore_latch_mode,
mtr)) { mtr)) {
@ -561,19 +560,13 @@ btr_pcur_move_backward_from_page(
ut_ad(btr_pcur_is_before_first_on_page(cursor)); ut_ad(btr_pcur_is_before_first_on_page(cursor));
ut_ad(!btr_pcur_is_before_first_in_tree(cursor)); ut_ad(!btr_pcur_is_before_first_in_tree(cursor));
const auto latch_mode = cursor->latch_mode;
ut_ad(latch_mode == BTR_SEARCH_LEAF || latch_mode == BTR_MODIFY_LEAF);
btr_pcur_store_position(cursor, mtr); btr_pcur_store_position(cursor, mtr);
mtr_commit(mtr); mtr_commit(mtr);
mtr_start(mtr); mtr_start(mtr);
static_assert(BTR_SEARCH_PREV == (4 | BTR_SEARCH_LEAF), ""); if (UNIV_UNLIKELY(cursor->restore_position(BTR_SEARCH_PREV, mtr)
if (UNIV_UNLIKELY(cursor->restore_position(
btr_latch_mode(4 | latch_mode), mtr)
== btr_pcur_t::CORRUPTED)) { == btr_pcur_t::CORRUPTED)) {
return true; return true;
} }
@ -605,7 +598,7 @@ btr_pcur_move_backward_from_page(
mtr->rollback_to_savepoint(1); mtr->rollback_to_savepoint(1);
ut_ad(block == mtr->at_savepoint(0)); ut_ad(block == mtr->at_savepoint(0));
cursor->latch_mode = latch_mode; cursor->latch_mode = BTR_SEARCH_LEAF;
cursor->old_rec = nullptr; cursor->old_rec = nullptr;
return false; return false;
} }
@ -622,7 +615,7 @@ btr_pcur_move_to_prev(
mtr_t* mtr) /*!< in: mtr */ mtr_t* mtr) /*!< in: mtr */
{ {
ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED); ut_ad(cursor->pos_state == BTR_PCUR_IS_POSITIONED);
ut_ad(cursor->latch_mode != BTR_NO_LATCHES); ut_ad(cursor->latch_mode == BTR_SEARCH_LEAF);
cursor->old_rec = nullptr; cursor->old_rec = nullptr;