/***********************************************************//**
Determines if it is possible to remove a secondary index entry.
Removal is possible if the secondary index entry does not refer to any
not delete marked version of a clustered index record where DB_TRX_ID
is newer than the purge view.
NOTE: This function should only be called by the purge thread, only
while holding a latch on the leaf page of the secondary index entry
(or keeping the buffer pool watch on the page). It is possible that
this function first returns TRUE and then FALSE, if a user transaction
inserts a record that the secondary index entry would refer to.
However, in that case, the user transaction would also re-insert the
secondary index entry after purge has removed it and released the leaf
page latch.
@return TRUE if the secondary index record can be purged */
UNIV_INTERN
ibool
row_purge_poss_sec(
/*===============*/
purge_node_t* node, /*!< in/out: row purge node */
dict_index_t* index, /*!< in: secondary index */
const dtuple_t* entry) /*!< in: secondary index entry */
{
ibool can_delete;
mtr_t mtr;
ut_ad(!dict_index_is_clust(index));
mtr_start(&mtr);
can_delete = !row_purge_reposition_pcur(BTR_SEARCH_LEAF, node, &mtr)
|| !row_vers_old_has_index_entry(TRUE,
btr_pcur_get_rec(&node->pcur),
&mtr, index, entry);
btr_pcur_commit_specify_mtr(&node->pcur, &mtr);
return(can_delete);
}
/***************************************************************
Removes a secondary index entry if possible. */
static
ibool
row_purge_remove_sec_if_poss_low(
/*=============================*/
/* out: TRUE if success or if not found */
purge_node_t* node, /* in: row purge node */
que_thr_t* thr, /* in: query thread */
dict_index_t* index, /* in: index */
dtuple_t* entry, /* in: index entry */
ulint mode) /* in: latch mode BTR_MODIFY_LEAF or
BTR_MODIFY_TREE */
{
btr_pcur_t pcur;
btr_cur_t* btr_cur;
ibool success;
ibool old_has;
ibool found;
ulint err;
mtr_t mtr;
mtr_t* mtr_vers;
UT_NOT_USED(thr);
log_free_check();
mtr_start(&mtr);
found = row_search_index_entry(index, entry, mode, &pcur, &mtr);
if (!found) {
/* Not found */
/* printf("PURGE:........sec entry not found\n"); */
/* dtuple_print(entry); */
btr_pcur_close(&pcur);
mtr_commit(&mtr);
return(TRUE);
}
btr_cur = btr_pcur_get_btr_cur(&pcur);
/* We should remove the index record if no later version of the row,
which cannot be purged yet, requires its existence. If some requires,
we should do nothing. */
mtr_vers = mem_alloc(sizeof(mtr_t));
mtr_start(mtr_vers);
success = row_purge_reposition_pcur(BTR_SEARCH_LEAF, node, mtr_vers);
if (success) {
old_has = row_vers_old_has_index_entry(TRUE,
btr_pcur_get_rec(&(node->pcur)),
mtr_vers, index, entry);
}
btr_pcur_commit_specify_mtr(&(node->pcur), mtr_vers);
mem_free(mtr_vers);
if (!success || !old_has) {
/* Remove the index record */
if (mode == BTR_MODIFY_LEAF) {
success = btr_cur_optimistic_delete(btr_cur, &mtr);
} else {
ut_ad(mode == BTR_MODIFY_TREE);
btr_cur_pessimistic_delete(&err, FALSE, btr_cur,
FALSE, &mtr);
if (err == DB_SUCCESS) {
success = TRUE;
} else if (err == DB_OUT_OF_FILE_SPACE) {
success = FALSE;
} else {
ut_a(0);
}
}
}
btr_pcur_close(&pcur);
mtr_commit(&mtr);
return(success);
}
/***********************************************************//**
Delete marks or removes a secondary index entry if found.
@return DB_SUCCESS, DB_FAIL, or DB_OUT_OF_FILE_SPACE */
static
ulint
row_undo_mod_del_mark_or_remove_sec_low(
/*====================================*/
undo_node_t* node, /*!< in: row undo node */
que_thr_t* thr, /*!< in: query thread */
dict_index_t* index, /*!< in: index */
dtuple_t* entry, /*!< in: index entry */
ulint mode) /*!< in: latch mode BTR_MODIFY_LEAF or
BTR_MODIFY_TREE */
{
btr_pcur_t pcur;
btr_cur_t* btr_cur;
ibool success;
ibool old_has;
ulint err;
mtr_t mtr;
mtr_t mtr_vers;
enum row_search_result search_result;
log_free_check();
mtr_start(&mtr);
btr_cur = btr_pcur_get_btr_cur(&pcur);
ut_ad(mode == BTR_MODIFY_TREE || mode == BTR_MODIFY_LEAF);
search_result = row_search_index_entry(index, entry, mode,
&pcur, &mtr);
switch (UNIV_EXPECT(search_result, ROW_FOUND)) {
case ROW_NOT_FOUND:
/* In crash recovery, the secondary index record may
be missing if the UPDATE did not have time to insert
the secondary index records before the crash. When we
are undoing that UPDATE in crash recovery, the record
may be missing.
In normal processing, if an update ends in a deadlock
before it has inserted all updated secondary index
records, then the undo will not find those records. */
err = DB_SUCCESS;
goto func_exit;
case ROW_FOUND:
break;
case ROW_BUFFERED:
case ROW_NOT_DELETED_REF:
/* These are invalid outcomes, because the mode passed
to row_search_index_entry() did not include any of the
flags BTR_INSERT, BTR_DELETE, or BTR_DELETE_MARK. */
ut_error;
}
/* We should remove the index record if no prior version of the row,
which cannot be purged yet, requires its existence. If some requires,
we should delete mark the record. */
mtr_start(&mtr_vers);
success = btr_pcur_restore_position(BTR_SEARCH_LEAF, &(node->pcur),
&mtr_vers);
ut_a(success);
old_has = row_vers_old_has_index_entry(FALSE,
btr_pcur_get_rec(&(node->pcur)),
&mtr_vers, index, entry);
if (old_has) {
err = btr_cur_del_mark_set_sec_rec(BTR_NO_LOCKING_FLAG,
btr_cur, TRUE, thr, &mtr);
ut_ad(err == DB_SUCCESS);
} else {
/* Remove the index record */
if (mode == BTR_MODIFY_LEAF) {
success = btr_cur_optimistic_delete(btr_cur, &mtr);
if (success) {
err = DB_SUCCESS;
} else {
err = DB_FAIL;
}
} else {
ut_ad(mode == BTR_MODIFY_TREE);
/* No need to distinguish RB_RECOVERY_PURGE here,
because we are deleting a secondary index record:
the distinction between RB_NORMAL and
RB_RECOVERY_PURGE only matters when deleting a
record that contains externally stored
columns. */
ut_ad(!dict_index_is_clust(index));
btr_cur_pessimistic_delete(&err, FALSE, btr_cur,
RB_NORMAL, &mtr);
/* The delete operation may fail if we have little
file space left: TODO: easiest to crash the database
and restart with more file space */
}
}
btr_pcur_commit_specify_mtr(&(node->pcur), &mtr_vers);
func_exit:
btr_pcur_close(&pcur);
mtr_commit(&mtr);
return(err);
}
