/***************************************************************
Checks if also the previous version of the clustered index record was
modified or inserted by the same transaction, and its undo number is such
that it should be undone in the same rollback. */
UNIV_INLINE
ibool
row_undo_mod_undo_also_prev_vers(
/*=============================*/
/* out: TRUE if also previous modify or
insert of this row should be undone */
undo_node_t* node, /* in: row undo node */
dulint* undo_no)/* out: the undo number */
{
trx_undo_rec_t* undo_rec;
trx_t* trx;
trx = node->trx;
if (0 != ut_dulint_cmp(node->new_trx_id, trx->id)) {
*undo_no = ut_dulint_zero;
return(FALSE);
}
undo_rec = trx_undo_get_undo_rec_low(node->new_roll_ptr, node->heap);
*undo_no = trx_undo_rec_get_undo_no(undo_rec);
return(ut_dulint_cmp(trx->roll_limit, *undo_no) <= 0);
}
/***************************************************************
Checks if also the previous version of the clustered index record was
modified or inserted by the same transaction, and its undo number is such
that it should be undone in the same rollback. */
UNIV_INLINE
ibool
row_undo_mod_undo_also_prev_vers(
/*=============================*/
/* out: TRUE if also previous modify or
insert of this row should be undone */
undo_node_t* node, /* in: row undo node */
que_thr_t* thr, /* in: query thread */
dulint* undo_no)/* out: the undo number */
{
trx_undo_rec_t* undo_rec;
ibool ret;
trx_t* trx;
UT_NOT_USED(thr);
trx = node->trx;
if (0 != ut_dulint_cmp(node->new_trx_id, trx->id)) {
return(FALSE);
}
undo_rec = trx_undo_get_undo_rec_low(node->new_roll_ptr, node->heap);
*undo_no = trx_undo_rec_get_undo_no(undo_rec);
if (ut_dulint_cmp(trx->roll_limit, *undo_no) <= 0) {
ret = TRUE;
} else {
ret = FALSE;
}
return(ret);
}
/***********************************************************//**
Checks if also the previous version of the clustered index record was
modified or inserted by the same transaction, and its undo number is such
that it should be undone in the same rollback.
@return TRUE if also previous modify or insert of this row should be undone */
static
ibool
row_undo_mod_undo_also_prev_vers(
/*=============================*/
undo_node_t* node, /*!< in: row undo node */
undo_no_t* undo_no)/*!< out: the undo number */
{
trx_undo_rec_t* undo_rec;
trx_t* trx;
trx = node->trx;
if (node->new_trx_id != trx->id) {
*undo_no = 0;
return(FALSE);
}
undo_rec = trx_undo_get_undo_rec_low(node->new_roll_ptr, node->heap);
*undo_no = trx_undo_rec_get_undo_no(undo_rec);
return(trx->roll_limit <= *undo_no);
}
/***********************************************************//**
Checks if also the previous version of the clustered index record was
modified or inserted by the same transaction, and its undo number is such
that it should be undone in the same rollback.
@return TRUE if also previous modify or insert of this row should be undone */
static
ibool
row_undo_mod_undo_also_prev_vers(
/*=============================*/
undo_node_t* node, /*!< in: row undo node */
undo_no_t* undo_no)/*!< out: the undo number */
{
trx_undo_rec_t* undo_rec;
trx_t* trx;
trx = node->trx;
if (0 != ut_dulint_cmp(node->new_trx_id, trx->id)) {
*undo_no = ut_dulint_zero;
return(FALSE);
}
undo_rec = trx_undo_get_undo_rec_low(node->new_roll_ptr, node->heap);
*undo_no = trx_undo_rec_get_undo_no(undo_rec);
return(ut_dulint_cmp(trx->roll_limit, *undo_no) <= 0);
}
/***********************************************************//**
Fetches an undo log record and does the undo for the recorded operation.
If none left, or a partial rollback completed, returns control to the
parent node, which is always a query thread node.
@return DB_SUCCESS if operation successfully completed, else error code */
static
ulint
row_undo(
/*=====*/
undo_node_t* node, /*!< in: row undo node */
que_thr_t* thr) /*!< in: query thread */
{
ulint err;
trx_t* trx;
roll_ptr_t roll_ptr;
ibool locked_data_dict;
ut_ad(node && thr);
trx = node->trx;
if (node->state == UNDO_NODE_FETCH_NEXT) {
node->undo_rec = trx_roll_pop_top_rec_of_trx(trx,
trx->roll_limit,
&roll_ptr,
node->heap);
if (!node->undo_rec) {
/* Rollback completed for this query thread */
thr->run_node = que_node_get_parent(node);
return(DB_SUCCESS);
}
node->roll_ptr = roll_ptr;
node->undo_no = trx_undo_rec_get_undo_no(node->undo_rec);
if (trx_undo_roll_ptr_is_insert(roll_ptr)) {
node->state = UNDO_NODE_INSERT;
} else {
node->state = UNDO_NODE_MODIFY;
}
} else if (node->state == UNDO_NODE_PREV_VERS) {
/* Undo should be done to the same clustered index record
again in this same rollback, restoring the previous version */
roll_ptr = node->new_roll_ptr;
node->undo_rec = trx_undo_get_undo_rec_low(roll_ptr,
node->heap);
node->roll_ptr = roll_ptr;
node->undo_no = trx_undo_rec_get_undo_no(node->undo_rec);
if (trx_undo_roll_ptr_is_insert(roll_ptr)) {
node->state = UNDO_NODE_INSERT;
} else {
node->state = UNDO_NODE_MODIFY;
}
}
/* Prevent DROP TABLE etc. while we are rolling back this row.
If we are doing a TABLE CREATE or some other dictionary operation,
then we already have dict_operation_lock locked in x-mode. Do not
try to lock again, because that would cause a hang. */
locked_data_dict = (trx->dict_operation_lock_mode == 0);
if (locked_data_dict) {
row_mysql_lock_data_dictionary(trx);
}
if (node->state == UNDO_NODE_INSERT) {
err = row_undo_ins(node);
node->state = UNDO_NODE_FETCH_NEXT;
} else {
ut_ad(node->state == UNDO_NODE_MODIFY);
err = row_undo_mod(node, thr);
}
if (locked_data_dict) {
row_mysql_unlock_data_dictionary(trx);
}
/* Do some cleanup */
btr_pcur_close(&(node->pcur));
mem_heap_empty(node->heap);
thr->run_node = node;
return(err);
}
/*****************************************************************//**
Constructs the version of a clustered index record which a consistent
read should see. We assume that the trx id stored in rec is such that
the consistent read should not see rec in its present version.
@return DB_SUCCESS or DB_MISSING_HISTORY */
UNIV_INTERN
ulint
row_vers_build_for_consistent_read(
/*===============================*/
const rec_t* rec, /*!< in: record in a clustered index; the
caller must have a latch on the page; this
latch locks the top of the stack of versions
of this records */
mtr_t* mtr, /*!< in: mtr holding the latch on rec */
dict_index_t* index, /*!< in: the clustered index */
ulint** offsets,/*!< in/out: offsets returned by
rec_get_offsets(rec, index) */
read_view_t* view, /*!< in: the consistent read view */
mem_heap_t** offset_heap,/*!< in/out: memory heap from which
the offsets are allocated */
mem_heap_t* in_heap,/*!< in: memory heap from which the memory for
*old_vers is allocated; memory for possible
intermediate versions is allocated and freed
locally within the function */
rec_t** old_vers)/*!< out, own: old version, or NULL if the
record does not exist in the view, that is,
it was freshly inserted afterwards */
{
const rec_t* version;
rec_t* prev_version;
trx_id_t trx_id;
mem_heap_t* heap = NULL;
byte* buf;
ulint err;
ut_ad(dict_index_is_clust(index));
ut_ad(mtr_memo_contains_page(mtr, rec, MTR_MEMO_PAGE_X_FIX)
|| mtr_memo_contains_page(mtr, rec, MTR_MEMO_PAGE_S_FIX));
#ifdef UNIV_SYNC_DEBUG
ut_ad(!rw_lock_own(&(purge_sys->latch), RW_LOCK_SHARED));
#endif /* UNIV_SYNC_DEBUG */
ut_ad(rec_offs_validate(rec, index, *offsets));
trx_id = row_get_rec_trx_id(rec, index, *offsets);
ut_ad(!read_view_sees_trx_id(view, trx_id));
rw_lock_s_lock(&(purge_sys->latch));
version = rec;
for (;;) {
mem_heap_t* heap2 = heap;
trx_undo_rec_t* undo_rec;
roll_ptr_t roll_ptr;
undo_no_t undo_no;
heap = mem_heap_create(1024);
/* If we have high-granularity consistent read view and
creating transaction of the view is the same as trx_id in
the record we see this record only in the case when
undo_no of the record is < undo_no in the view. */
if (view->type == VIEW_HIGH_GRANULARITY
&& ut_dulint_cmp(view->creator_trx_id, trx_id) == 0) {
roll_ptr = row_get_rec_roll_ptr(version, index,
*offsets);
undo_rec = trx_undo_get_undo_rec_low(roll_ptr, heap);
undo_no = trx_undo_rec_get_undo_no(undo_rec);
mem_heap_empty(heap);
if (ut_dulint_cmp(view->undo_no, undo_no) > 0) {
/* The view already sees this version: we can
copy it to in_heap and return */
#if defined UNIV_DEBUG || defined UNIV_BLOB_LIGHT_DEBUG
ut_a(!rec_offs_any_null_extern(
version, *offsets));
#endif /* UNIV_DEBUG || UNIV_BLOB_LIGHT_DEBUG */
buf = mem_heap_alloc(in_heap,
rec_offs_size(*offsets));
*old_vers = rec_copy(buf, version, *offsets);
rec_offs_make_valid(*old_vers, index,
*offsets);
err = DB_SUCCESS;
break;
}
}
err = trx_undo_prev_version_build(rec, mtr, version, index,
*offsets, heap,
&prev_version);
if (heap2) {
mem_heap_free(heap2); /* free version */
}
if (err != DB_SUCCESS) {
break;
}
if (prev_version == NULL) {
/* It was a freshly inserted version */
*old_vers = NULL;
err = DB_SUCCESS;
break;
}
*offsets = rec_get_offsets(prev_version, index, *offsets,
ULINT_UNDEFINED, offset_heap);
#if defined UNIV_DEBUG || defined UNIV_BLOB_LIGHT_DEBUG
ut_a(!rec_offs_any_null_extern(prev_version, *offsets));
#endif /* UNIV_DEBUG || UNIV_BLOB_LIGHT_DEBUG */
trx_id = row_get_rec_trx_id(prev_version, index, *offsets);
if (read_view_sees_trx_id(view, trx_id)) {
/* The view already sees this version: we can copy
it to in_heap and return */
buf = mem_heap_alloc(in_heap, rec_offs_size(*offsets));
*old_vers = rec_copy(buf, prev_version, *offsets);
rec_offs_make_valid(*old_vers, index, *offsets);
err = DB_SUCCESS;
break;
}
version = prev_version;
}/* for (;;) */
mem_heap_free(heap);
rw_lock_s_unlock(&(purge_sys->latch));
return(err);
}
