diff options
Diffstat (limited to '')
| -rw-r--r-- | storage/innobase/row/row0vers.cc | 1353 |
1 files changed, 1353 insertions, 0 deletions
diff --git a/storage/innobase/row/row0vers.cc b/storage/innobase/row/row0vers.cc new file mode 100644 index 00000000..b7378607 --- /dev/null +++ b/storage/innobase/row/row0vers.cc @@ -0,0 +1,1353 @@ +/***************************************************************************** + +Copyright (c) 1997, 2017, Oracle and/or its affiliates. All Rights Reserved. +Copyright (c) 2017, 2021, MariaDB Corporation. + +This program is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free Software +Foundation; version 2 of the License. + +This program is distributed in the hope that it will be useful, but WITHOUT +ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS +FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. + +You should have received a copy of the GNU General Public License along with +this program; if not, write to the Free Software Foundation, Inc., +51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA + +*****************************************************************************/ + +/**************************************************//** +@file row/row0vers.cc +Row versions + +Created 2/6/1997 Heikki Tuuri +*******************************************************/ + +#include "row0vers.h" +#include "dict0dict.h" +#include "dict0boot.h" +#include "btr0btr.h" +#include "mach0data.h" +#include "trx0rseg.h" +#include "trx0trx.h" +#include "trx0roll.h" +#include "trx0undo.h" +#include "trx0purge.h" +#include "trx0rec.h" +#include "que0que.h" +#include "row0row.h" +#include "row0upd.h" +#include "rem0cmp.h" +#include "lock0lock.h" +#include "row0mysql.h" + +/** Check whether all non-virtual index fields are equal. +@param[in] index the secondary index +@param[in] a first index entry to compare +@param[in] b second index entry to compare +@return whether all non-virtual fields are equal */ +static +bool +row_vers_non_virtual_fields_equal( + const dict_index_t* index, + const dfield_t* a, + const dfield_t* b) +{ + const dict_field_t* end = &index->fields[index->n_fields]; + + for (const dict_field_t* ifield = index->fields; ifield != end; + ifield++) { + if (!ifield->col->is_virtual() + && cmp_dfield_dfield(a++, b++)) { + return false; + } + } + + return true; +} + +/** Determine if an active transaction has inserted or modified a secondary +index record. +@param[in,out] caller_trx trx of current thread +@param[in] clust_rec clustered index record +@param[in] clust_index clustered index +@param[in] rec secondary index record +@param[in] index secondary index +@param[in] offsets rec_get_offsets(rec, index) +@param[in,out] mtr mini-transaction +@return the active transaction; state must be rechecked after +trx_mutex_enter(), and trx->release_reference() must be invoked +@retval NULL if the record was committed */ +UNIV_INLINE +trx_t* +row_vers_impl_x_locked_low( + trx_t* caller_trx, + const rec_t* clust_rec, + dict_index_t* clust_index, + const rec_t* rec, + dict_index_t* index, + const rec_offs* offsets, + mtr_t* mtr) +{ + trx_id_t trx_id; + rec_t* prev_version = NULL; + rec_offs clust_offsets_[REC_OFFS_NORMAL_SIZE]; + rec_offs* clust_offsets; + mem_heap_t* heap; + dtuple_t* ientry = NULL; + mem_heap_t* v_heap = NULL; + dtuple_t* cur_vrow = NULL; + + rec_offs_init(clust_offsets_); + + DBUG_ENTER("row_vers_impl_x_locked_low"); + + ut_ad(rec_offs_validate(rec, index, offsets)); + + if (ulint trx_id_offset = clust_index->trx_id_offset) { + trx_id = mach_read_from_6(clust_rec + trx_id_offset); + if (trx_id == 0) { + /* The transaction history was already purged. */ + DBUG_RETURN(0); + } + } + + heap = mem_heap_create(1024); + + clust_offsets = rec_get_offsets(clust_rec, clust_index, clust_offsets_, + clust_index->n_core_fields, + ULINT_UNDEFINED, &heap); + + trx_id = row_get_rec_trx_id(clust_rec, clust_index, clust_offsets); + if (trx_id == 0) { + /* The transaction history was already purged. */ + mem_heap_free(heap); + DBUG_RETURN(0); + } + + ut_ad(!clust_index->table->is_temporary()); + + trx_t* trx; + + if (trx_id == caller_trx->id) { + trx = caller_trx; + trx->reference(); + } else { + trx = trx_sys.find(caller_trx, trx_id); + if (trx == 0) { + /* The transaction that modified or inserted + clust_rec is no longer active, or it is + corrupt: no implicit lock on rec */ + lock_check_trx_id_sanity(trx_id, clust_rec, + clust_index, clust_offsets); + mem_heap_free(heap); + DBUG_RETURN(0); + } + } + + const ulint comp = page_rec_is_comp(rec); + ut_ad(index->table == clust_index->table); + ut_ad(!!comp == dict_table_is_comp(index->table)); + ut_ad(!comp == !page_rec_is_comp(clust_rec)); + + const ulint rec_del = rec_get_deleted_flag(rec, comp); + + if (dict_index_has_virtual(index)) { + ulint est_size = DTUPLE_EST_ALLOC(index->n_fields); + + /* Allocate the dtuple for virtual columns extracted from undo + log with its own heap, so to avoid it being freed as we + iterating in the version loop below. */ + v_heap = mem_heap_create(est_size); + ientry = row_rec_to_index_entry(rec, index, offsets, v_heap); + } + + /* We look up if some earlier version, which was modified by + the trx_id transaction, of the clustered index record would + require rec to be in a different state (delete marked or + unmarked, or have different field values, or not existing). If + there is such a version, then rec was modified by the trx_id + transaction, and it has an implicit x-lock on rec. Note that + if clust_rec itself would require rec to be in a different + state, then the trx_id transaction has not yet had time to + modify rec, and does not necessarily have an implicit x-lock + on rec. */ + + for (const rec_t* version = clust_rec;; version = prev_version) { + row_ext_t* ext; + dtuple_t* row; + dtuple_t* entry; + ulint vers_del; + trx_id_t prev_trx_id; + mem_heap_t* old_heap = heap; + dtuple_t* vrow = NULL; + + /* We keep the semaphore in mtr on the clust_rec page, so + that no other transaction can update it and get an + implicit x-lock on rec until mtr_commit(mtr). */ + + heap = mem_heap_create(1024); + + trx_undo_prev_version_build( + clust_rec, mtr, version, clust_index, clust_offsets, + heap, &prev_version, NULL, + dict_index_has_virtual(index) ? &vrow : NULL, 0); + + trx_mutex_enter(trx); + const bool committed = trx_state_eq( + trx, TRX_STATE_COMMITTED_IN_MEMORY); + trx_mutex_exit(trx); + + /* The oldest visible clustered index version must not be + delete-marked, because we never start a transaction by + inserting a delete-marked record. */ + ut_ad(committed || prev_version + || !rec_get_deleted_flag(version, comp)); + + /* Free version and clust_offsets. */ + mem_heap_free(old_heap); + + if (committed) { + goto not_locked; + } + + if (prev_version == NULL) { + + /* We reached the oldest visible version without + finding an older version of clust_rec that would + match the secondary index record. If the secondary + index record is not delete marked, then clust_rec + is considered the correct match of the secondary + index record and hence holds the implicit lock. */ + + if (rec_del) { + /* The secondary index record is del marked. + So, the implicit lock holder of clust_rec + did not modify the secondary index record yet, + and is not holding an implicit lock on it. + + This assumes that whenever a row is inserted + or updated, the leaf page record always is + created with a clear delete-mark flag. + (We never insert a delete-marked record.) */ +not_locked: + trx->release_reference(); + trx = 0; + } + + break; + } + + clust_offsets = rec_get_offsets( + prev_version, clust_index, clust_offsets_, + clust_index->n_core_fields, + ULINT_UNDEFINED, &heap); + + vers_del = rec_get_deleted_flag(prev_version, comp); + + prev_trx_id = row_get_rec_trx_id(prev_version, clust_index, + clust_offsets); + + /* The stack of versions is locked by mtr. Thus, it + is safe to fetch the prefixes for externally stored + columns. */ + + row = row_build(ROW_COPY_POINTERS, clust_index, prev_version, + clust_offsets, + NULL, NULL, NULL, &ext, heap); + + if (dict_index_has_virtual(index)) { + if (vrow) { + /* Keep the virtual row info for the next + version */ + cur_vrow = dtuple_copy(vrow, v_heap); + dtuple_dup_v_fld(cur_vrow, v_heap); + } + + if (!cur_vrow) { + /* Build index entry out of row */ + entry = row_build_index_entry(row, ext, index, + heap); + + /* entry could only be NULL (the + clustered index record could contain + BLOB pointers that are NULL) if we + were accessing a freshly inserted + record before it was fully inserted. + prev_version cannot possibly be such + an incomplete record, because its + transaction would have to be committed + in order for later versions of the + record to be able to exist. */ + ut_ad(entry); + + /* If the indexed virtual columns has changed, + there must be log record to generate vrow. + Otherwise, it is not changed, so no need + to compare */ + if (!row_vers_non_virtual_fields_equal( + index, + ientry->fields, entry->fields)) { + if (rec_del != vers_del) { + break; + } + } else if (!rec_del) { + break; + } + + goto result_check; + } else { + ut_ad(row->n_v_fields == cur_vrow->n_v_fields); + dtuple_copy_v_fields(row, cur_vrow); + } + } + + entry = row_build_index_entry(row, ext, index, heap); + + /* entry could only be NULL (the clustered index + record could contain BLOB pointers that are NULL) if + we were accessing a freshly inserted record before it + was fully inserted. prev_version cannot possibly be + such an incomplete record, because its transaction + would have to be committed in order for later versions + of the record to be able to exist. */ + ut_ad(entry); + + /* If we get here, we know that the trx_id transaction + modified prev_version. Let us check if prev_version + would require rec to be in a different state. */ + + /* The previous version of clust_rec must be + accessible, because clust_rec was not a fresh insert. + There is no guarantee that the transaction is still + active. */ + + /* We check if entry and rec are identified in the alphabetical + ordering */ + if (0 == cmp_dtuple_rec(entry, rec, offsets)) { + /* The delete marks of rec and prev_version should be + equal for rec to be in the state required by + prev_version */ + + if (rec_del != vers_del) { + + break; + } + + /* It is possible that the row was updated so that the + secondary index record remained the same in + alphabetical ordering, but the field values changed + still. For example, 'abc' -> 'ABC'. Check also that. */ + + dtuple_set_types_binary( + entry, dtuple_get_n_fields(entry)); + + if (0 != cmp_dtuple_rec(entry, rec, offsets)) { + + break; + } + + } else if (!rec_del) { + /* The delete mark should be set in rec for it to be + in the state required by prev_version */ + + break; + } + +result_check: + if (trx->id != prev_trx_id) { + /* prev_version was the first version modified by + the trx_id transaction: no implicit x-lock */ + goto not_locked; + } + } + + if (trx) { + DBUG_PRINT("info", ("Implicit lock is held by trx:" TRX_ID_FMT, + trx_id)); + } + + if (v_heap != NULL) { + mem_heap_free(v_heap); + } + + mem_heap_free(heap); + DBUG_RETURN(trx); +} + +/** Determine if an active transaction has inserted or modified a secondary +index record. +@param[in,out] caller_trx trx of current thread +@param[in] rec secondary index record +@param[in] index secondary index +@param[in] offsets rec_get_offsets(rec, index) +@return the active transaction; state must be rechecked after +trx_mutex_enter(), and trx->release_reference() must be invoked +@retval NULL if the record was committed */ +trx_t* +row_vers_impl_x_locked( + trx_t* caller_trx, + const rec_t* rec, + dict_index_t* index, + const rec_offs* offsets) +{ + mtr_t mtr; + trx_t* trx; + const rec_t* clust_rec; + dict_index_t* clust_index; + + ut_ad(!lock_mutex_own()); + + mtr_start(&mtr); + + /* Search for the clustered index record. The latch on the + page of clust_rec locks the top of the stack of versions. The + bottom of the version stack is not locked; oldest versions may + disappear by the fact that transactions may be committed and + collected by the purge. This is not a problem, because we are + only interested in active transactions. */ + + clust_rec = row_get_clust_rec( + BTR_SEARCH_LEAF, rec, index, &clust_index, &mtr); + + if (!clust_rec) { + /* In a rare case it is possible that no clust rec is found + for a secondary index record: if in row0umod.cc + row_undo_mod_remove_clust_low() we have already removed the + clust rec, while purge is still cleaning and removing + secondary index records associated with earlier versions of + the clustered index record. In that case there cannot be + any implicit lock on the secondary index record, because + an active transaction which has modified the secondary index + record has also modified the clustered index record. And in + a rollback we always undo the modifications to secondary index + records before the clustered index record. */ + + trx = 0; + } else { + trx = row_vers_impl_x_locked_low( + caller_trx, clust_rec, clust_index, rec, index, + offsets, &mtr); + + ut_ad(trx == 0 || trx->is_referenced()); + } + + mtr_commit(&mtr); + + return(trx); +} + +/** build virtual column value from current cluster index record data +@param[in,out] row the cluster index row in dtuple form +@param[in] clust_index clustered index +@param[in] index the secondary index +@param[in] heap heap used to build virtual dtuple. */ +static +bool +row_vers_build_clust_v_col( + dtuple_t* row, + dict_index_t* clust_index, + dict_index_t* index, + mem_heap_t* heap) +{ + THD* thd= current_thd; + TABLE* maria_table= 0; + + ut_ad(dict_index_has_virtual(index)); + ut_ad(index->table == clust_index->table); + + DEBUG_SYNC(current_thd, "ib_clust_v_col_before_row_allocated"); + + ib_vcol_row vc(nullptr); + byte *record = vc.record(thd, index, &maria_table); + + ut_ad(maria_table); + + for (ulint i = 0; i < dict_index_get_n_fields(index); i++) { + const dict_col_t* c = dict_index_get_nth_col(index, i); + + if (c->is_virtual()) { + const dict_v_col_t* col + = reinterpret_cast<const dict_v_col_t*>(c); + + dfield_t *vfield = innobase_get_computed_value( + row, col, clust_index, &vc.heap, + heap, NULL, thd, maria_table, record, NULL, + NULL, NULL); + if (!vfield) { + innobase_report_computed_value_failed(row); + ut_ad(0); + return false; + } + } + } + + return true; +} + +/** Build latest virtual column data from undo log +@param[in] in_purge whether this is the purge thread +@param[in] rec clustered index record +@param[in] clust_index clustered index +@param[in,out] clust_offsets offsets on the clustered index record +@param[in] index the secondary index +@param[in] roll_ptr the rollback pointer for the purging record +@param[in] trx_id trx id for the purging record +@param[in,out] v_heap heap used to build vrow +@param[out] v_row dtuple holding the virtual rows +@param[in,out] mtr mtr holding the latch on rec */ +static +void +row_vers_build_cur_vrow_low( + bool in_purge, + const rec_t* rec, + dict_index_t* clust_index, + rec_offs* clust_offsets, + dict_index_t* index, + roll_ptr_t roll_ptr, + trx_id_t trx_id, + mem_heap_t* v_heap, + dtuple_t** vrow, + mtr_t* mtr) +{ + const rec_t* version; + rec_t* prev_version; + mem_heap_t* heap = NULL; + ulint num_v = dict_table_get_n_v_cols(index->table); + const dfield_t* field; + ulint i; + bool all_filled = false; + + *vrow = dtuple_create_with_vcol(v_heap, 0, num_v); + dtuple_init_v_fld(*vrow); + + for (i = 0; i < num_v; i++) { + dfield_get_type(dtuple_get_nth_v_field(*vrow, i))->mtype + = DATA_MISSING; + } + + version = rec; + + /* If this is called by purge thread, set TRX_UNDO_PREV_IN_PURGE + bit to search the undo log until we hit the current undo log with + roll_ptr */ + const ulint status = in_purge + ? TRX_UNDO_PREV_IN_PURGE | TRX_UNDO_GET_OLD_V_VALUE + : TRX_UNDO_GET_OLD_V_VALUE; + + while (!all_filled) { + mem_heap_t* heap2 = heap; + heap = mem_heap_create(1024); + roll_ptr_t cur_roll_ptr = row_get_rec_roll_ptr( + version, clust_index, clust_offsets); + + trx_undo_prev_version_build( + rec, mtr, version, clust_index, clust_offsets, + heap, &prev_version, NULL, vrow, status); + + if (heap2) { + mem_heap_free(heap2); + } + + if (!prev_version) { + /* Versions end here */ + break; + } + + clust_offsets = rec_get_offsets(prev_version, clust_index, + NULL, + clust_index->n_core_fields, + ULINT_UNDEFINED, &heap); + + ulint entry_len = dict_index_get_n_fields(index); + + all_filled = true; + + for (i = 0; i < entry_len; i++) { + const dict_col_t* col + = dict_index_get_nth_col(index, i); + + if (!col->is_virtual()) { + continue; + } + + const dict_v_col_t* v_col + = reinterpret_cast<const dict_v_col_t*>(col); + field = dtuple_get_nth_v_field(*vrow, v_col->v_pos); + + if (dfield_get_type(field)->mtype == DATA_MISSING) { + all_filled = false; + break; + } + + } + + trx_id_t rec_trx_id = row_get_rec_trx_id( + prev_version, clust_index, clust_offsets); + + if (rec_trx_id < trx_id || roll_ptr == cur_roll_ptr) { + break; + } + + version = prev_version; + } + + mem_heap_free(heap); +} + +/** Check a virtual column value index secondary virtual index matches +that of current cluster index record, which is recreated from information +stored in undo log +@param[in] rec record in the clustered index +@param[in] icentry the index entry built from a cluster row +@param[in] clust_index cluster index +@param[in] clust_offsets offsets on the cluster record +@param[in] index the secondary index +@param[in] ientry the secondary index entry +@param[in] roll_ptr the rollback pointer for the purging record +@param[in] trx_id trx id for the purging record +@param[in,out] v_heap heap used to build virtual dtuple +@param[in,out] v_row dtuple holding the virtual rows (if needed) +@param[in] mtr mtr holding the latch on rec +@return true if matches, false otherwise */ +static +bool +row_vers_vc_matches_cluster( + const rec_t* rec, + const dtuple_t* icentry, + dict_index_t* clust_index, + rec_offs* clust_offsets, + dict_index_t* index, + const dtuple_t* ientry, + roll_ptr_t roll_ptr, + trx_id_t trx_id, + mem_heap_t* v_heap, + dtuple_t** vrow, + mtr_t* mtr) +{ + const rec_t* version; + rec_t* prev_version; + mem_heap_t* heap2; + mem_heap_t* heap = NULL; + mem_heap_t* tuple_heap; + ulint num_v = dict_table_get_n_v_cols(index->table); + bool compare[REC_MAX_N_FIELDS]; + ulint n_fields = dtuple_get_n_fields(ientry); + ulint n_non_v_col = 0; + ulint n_cmp_v_col = 0; + const dfield_t* field1; + dfield_t* field2; + ulint i; + + /* First compare non-virtual columns (primary keys) */ + ut_ad(index->n_fields == n_fields); + ut_ad(n_fields == dtuple_get_n_fields(icentry)); + { + const dfield_t* a = ientry->fields; + const dfield_t* b = icentry->fields; + + for (const dict_field_t *ifield = index->fields, + *const end = &index->fields[index->n_fields]; + ifield != end; ifield++, a++, b++) { + if (!ifield->col->is_virtual()) { + if (cmp_dfield_dfield(a, b)) { + return false; + } + n_non_v_col++; + } + } + } + + tuple_heap = mem_heap_create(1024); + + ut_ad(n_fields > n_non_v_col); + + *vrow = dtuple_create_with_vcol(v_heap ? v_heap : tuple_heap, 0, num_v); + dtuple_init_v_fld(*vrow); + + for (i = 0; i < num_v; i++) { + dfield_get_type(dtuple_get_nth_v_field(*vrow, i))->mtype + = DATA_MISSING; + compare[i] = false; + } + + version = rec; + + while (n_cmp_v_col < n_fields - n_non_v_col) { + heap2 = heap; + heap = mem_heap_create(1024); + roll_ptr_t cur_roll_ptr = row_get_rec_roll_ptr( + version, clust_index, clust_offsets); + + ut_ad(cur_roll_ptr != 0); + ut_ad(roll_ptr != 0); + + trx_undo_prev_version_build( + rec, mtr, version, clust_index, clust_offsets, + heap, &prev_version, NULL, vrow, + TRX_UNDO_PREV_IN_PURGE | TRX_UNDO_GET_OLD_V_VALUE); + + if (heap2) { + mem_heap_free(heap2); + } + + if (!prev_version) { + /* Versions end here */ + goto func_exit; + } + + clust_offsets = rec_get_offsets(prev_version, clust_index, + NULL, + clust_index->n_core_fields, + ULINT_UNDEFINED, &heap); + + ulint entry_len = dict_index_get_n_fields(index); + + for (i = 0; i < entry_len; i++) { + const dict_field_t* ind_field + = dict_index_get_nth_field(index, i); + const dict_col_t* col = ind_field->col; + field1 = dtuple_get_nth_field(ientry, i); + + if (!col->is_virtual()) { + continue; + } + + const dict_v_col_t* v_col + = reinterpret_cast<const dict_v_col_t*>(col); + field2 + = dtuple_get_nth_v_field(*vrow, v_col->v_pos); + + if ((dfield_get_type(field2)->mtype != DATA_MISSING) + && (!compare[v_col->v_pos])) { + + if (ind_field->prefix_len != 0 + && !dfield_is_null(field2) + && field2->len > ind_field->prefix_len) { + field2->len = ind_field->prefix_len; + } + + /* The index field mismatch */ + if (v_heap + || cmp_dfield_dfield(field2, field1) != 0) { + if (v_heap) { + dtuple_dup_v_fld(*vrow, v_heap); + } + + mem_heap_free(tuple_heap); + mem_heap_free(heap); + return(false); + } + + compare[v_col->v_pos] = true; + n_cmp_v_col++; + } + } + + trx_id_t rec_trx_id = row_get_rec_trx_id( + prev_version, clust_index, clust_offsets); + + if (rec_trx_id < trx_id || roll_ptr == cur_roll_ptr) { + break; + } + + version = prev_version; + } + +func_exit: + if (n_cmp_v_col == 0) { + *vrow = NULL; + } + + mem_heap_free(tuple_heap); + mem_heap_free(heap); + + /* FIXME: In the case of n_cmp_v_col is not the same as + n_fields - n_non_v_col, callback is needed to compare the rest + columns. At the timebeing, we will need to return true */ + return (true); +} + +/** Build a dtuple contains virtual column data for current cluster index +@param[in] in_purge called by purge thread +@param[in] rec cluster index rec +@param[in] clust_index cluster index +@param[in] clust_offsets cluster rec offset +@param[in] index secondary index +@param[in] roll_ptr roll_ptr for the purge record +@param[in] trx_id transaction ID on the purging record +@param[in,out] heap heap memory +@param[in,out] v_heap heap memory to keep virtual colum dtuple +@param[in] mtr mtr holding the latch on rec +@return dtuple contains virtual column data */ +static +dtuple_t* +row_vers_build_cur_vrow( + bool in_purge, + const rec_t* rec, + dict_index_t* clust_index, + rec_offs** clust_offsets, + dict_index_t* index, + roll_ptr_t roll_ptr, + trx_id_t trx_id, + mem_heap_t* heap, + mem_heap_t* v_heap, + mtr_t* mtr) +{ + dtuple_t* cur_vrow = NULL; + + roll_ptr_t t_roll_ptr = row_get_rec_roll_ptr( + rec, clust_index, *clust_offsets); + + /* if the row is newly inserted, then the virtual + columns need to be computed */ + if (trx_undo_roll_ptr_is_insert(t_roll_ptr)) { + + ut_ad(!rec_get_deleted_flag(rec, page_rec_is_comp(rec))); + + /* This is a newly inserted record and cannot + be deleted, So the externally stored field + cannot be freed yet. */ + dtuple_t* row = row_build(ROW_COPY_POINTERS, clust_index, + rec, *clust_offsets, + NULL, NULL, NULL, NULL, heap); + + if (!row_vers_build_clust_v_col(row, clust_index, index, + heap)) { + return nullptr; + } + + cur_vrow = dtuple_copy(row, v_heap); + dtuple_dup_v_fld(cur_vrow, v_heap); + } else { + /* Try to fetch virtual column data from undo log */ + row_vers_build_cur_vrow_low( + in_purge, rec, clust_index, *clust_offsets, + index, roll_ptr, trx_id, v_heap, &cur_vrow, mtr); + } + + *clust_offsets = rec_get_offsets(rec, clust_index, NULL, + clust_index->n_core_fields, + ULINT_UNDEFINED, &heap); + return(cur_vrow); +} + +/** Finds out if a version of the record, where the version >= the current +purge view, should have ientry as its secondary index entry. We check +if there is any not delete marked version of the record where the trx +id >= purge view, and the secondary index entry == ientry; exactly in +this case we return TRUE. +@param[in] also_curr TRUE if also rec is included in the versions + to search; otherwise only versions prior + to it are searched +@param[in] rec record in the clustered index; the caller + must have a latch on the page +@param[in] mtr mtr holding the latch on rec; it will + also hold the latch on purge_view +@param[in] index secondary index +@param[in] ientry secondary index entry +@param[in] roll_ptr roll_ptr for the purge record +@param[in] trx_id transaction ID on the purging record +@return TRUE if earlier version should have */ +bool +row_vers_old_has_index_entry( + bool also_curr, + const rec_t* rec, + mtr_t* mtr, + dict_index_t* index, + const dtuple_t* ientry, + roll_ptr_t roll_ptr, + trx_id_t trx_id) +{ + const rec_t* version; + rec_t* prev_version; + dict_index_t* clust_index; + rec_offs* clust_offsets; + mem_heap_t* heap; + mem_heap_t* heap2; + dtuple_t* row; + const dtuple_t* entry; + ulint comp; + dtuple_t* vrow = NULL; + mem_heap_t* v_heap = NULL; + dtuple_t* cur_vrow = NULL; + + ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX + | MTR_MEMO_PAGE_S_FIX)); + clust_index = dict_table_get_first_index(index->table); + + comp = page_rec_is_comp(rec); + ut_ad(!dict_table_is_comp(index->table) == !comp); + heap = mem_heap_create(1024); + clust_offsets = rec_get_offsets(rec, clust_index, NULL, + clust_index->n_core_fields, + ULINT_UNDEFINED, &heap); + + if (dict_index_has_virtual(index)) { + v_heap = mem_heap_create(100); + } + + DBUG_EXECUTE_IF("ib_purge_virtual_index_crash", + DBUG_SUICIDE();); + + if (also_curr && !rec_get_deleted_flag(rec, comp)) { + row_ext_t* ext; + + /* The top of the stack of versions is locked by the + mtr holding a latch on the page containing the + clustered index record. The bottom of the stack is + locked by the fact that the purge_sys.view must + 'overtake' any read view of an active transaction. + Thus, it is safe to fetch the prefixes for + externally stored columns. */ + row = row_build(ROW_COPY_POINTERS, clust_index, + rec, clust_offsets, + NULL, NULL, NULL, &ext, heap); + + if (dict_index_has_virtual(index)) { + + +#ifdef DBUG_OFF +# define dbug_v_purge false +#else /* DBUG_OFF */ + bool dbug_v_purge = false; +#endif /* DBUG_OFF */ + + DBUG_EXECUTE_IF( + "ib_purge_virtual_index_callback", + dbug_v_purge = true;); + + roll_ptr_t t_roll_ptr = row_get_rec_roll_ptr( + rec, clust_index, clust_offsets); + + /* if the row is newly inserted, then the virtual + columns need to be computed */ + if (trx_undo_roll_ptr_is_insert(t_roll_ptr) + || dbug_v_purge) { + + if (!row_vers_build_clust_v_col( + row, clust_index, index, heap)) { + goto unsafe_to_purge; + } + + entry = row_build_index_entry( + row, ext, index, heap); + if (entry && !dtuple_coll_cmp(ientry, entry)) { + goto unsafe_to_purge; + } + } else { + /* Build index entry out of row */ + entry = row_build_index_entry(row, ext, index, heap); + /* entry could only be NULL if + the clustered index record is an uncommitted + inserted record whose BLOBs have not been + written yet. The secondary index record + can be safely removed, because it cannot + possibly refer to this incomplete + clustered index record. (Insert would + always first be completed for the + clustered index record, then proceed to + secondary indexes.) */ + + if (entry && row_vers_vc_matches_cluster( + rec, entry, + clust_index, clust_offsets, + index, ientry, roll_ptr, + trx_id, NULL, &vrow, mtr)) { + goto unsafe_to_purge; + } + } + clust_offsets = rec_get_offsets(rec, clust_index, NULL, + clust_index + ->n_core_fields, + ULINT_UNDEFINED, &heap); + } else { + + entry = row_build_index_entry( + row, ext, index, heap); + + /* If entry == NULL, the record contains unset BLOB + pointers. This must be a freshly inserted record. If + this is called from + row_purge_remove_sec_if_poss_low(), the thread will + hold latches on the clustered index and the secondary + index. Because the insert works in three steps: + + (1) insert the record to clustered index + (2) store the BLOBs and update BLOB pointers + (3) insert records to secondary indexes + + the purge thread can safely ignore freshly inserted + records and delete the secondary index record. The + thread that inserted the new record will be inserting + the secondary index records. */ + + /* NOTE that we cannot do the comparison as binary + fields because the row is maybe being modified so that + the clustered index record has already been updated to + a different binary value in a char field, but the + collation identifies the old and new value anyway! */ + if (entry && !dtuple_coll_cmp(ientry, entry)) { +unsafe_to_purge: + mem_heap_free(heap); + + if (v_heap) { + mem_heap_free(v_heap); + } + return true; + } + } + } else if (dict_index_has_virtual(index)) { + /* The current cluster index record could be + deleted, but the previous version of it might not. We will + need to get the virtual column data from undo record + associated with current cluster index */ + + cur_vrow = row_vers_build_cur_vrow( + also_curr, rec, clust_index, &clust_offsets, + index, roll_ptr, trx_id, heap, v_heap, mtr); + } + + version = rec; + + for (;;) { + heap2 = heap; + heap = mem_heap_create(1024); + vrow = NULL; + + trx_undo_prev_version_build(rec, mtr, version, + clust_index, clust_offsets, + heap, &prev_version, NULL, + dict_index_has_virtual(index) + ? &vrow : NULL, 0); + mem_heap_free(heap2); /* free version and clust_offsets */ + + if (!prev_version) { + /* Versions end here */ + mem_heap_free(heap); + + if (v_heap) { + mem_heap_free(v_heap); + } + + return false; + } + + clust_offsets = rec_get_offsets(prev_version, clust_index, + NULL, + clust_index->n_core_fields, + ULINT_UNDEFINED, &heap); + + if (dict_index_has_virtual(index)) { + if (vrow) { + /* Keep the virtual row info for the next + version, unless it is changed */ + mem_heap_empty(v_heap); + cur_vrow = dtuple_copy(vrow, v_heap); + dtuple_dup_v_fld(cur_vrow, v_heap); + } + + if (!cur_vrow) { + /* Nothing for this index has changed, + continue */ + version = prev_version; + continue; + } + } + + if (!rec_get_deleted_flag(prev_version, comp)) { + row_ext_t* ext; + + /* The stack of versions is locked by mtr. + Thus, it is safe to fetch the prefixes for + externally stored columns. */ + row = row_build(ROW_COPY_POINTERS, clust_index, + prev_version, clust_offsets, + NULL, NULL, NULL, &ext, heap); + + if (dict_index_has_virtual(index)) { + ut_ad(cur_vrow); + ut_ad(row->n_v_fields == cur_vrow->n_v_fields); + dtuple_copy_v_fields(row, cur_vrow); + } + + entry = row_build_index_entry(row, ext, index, heap); + + /* If entry == NULL, the record contains unset + BLOB pointers. This must be a freshly + inserted record that we can safely ignore. + For the justification, see the comments after + the previous row_build_index_entry() call. */ + + /* NOTE that we cannot do the comparison as binary + fields because maybe the secondary index record has + already been updated to a different binary value in + a char field, but the collation identifies the old + and new value anyway! */ + + if (entry && !dtuple_coll_cmp(ientry, entry)) { + goto unsafe_to_purge; + } + } + + version = prev_version; + } +} + +/*****************************************************************//** +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 */ +dberr_t +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 */ + rec_offs** offsets,/*!< in/out: offsets returned by + rec_get_offsets(rec, index) */ + ReadView* 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 history is missing or the record + does not exist in the view, that is, + it was freshly inserted afterwards */ + dtuple_t** vrow) /*!< out: virtual row */ +{ + const rec_t* version; + rec_t* prev_version; + trx_id_t trx_id; + mem_heap_t* heap = NULL; + byte* buf; + dberr_t err; + + ut_ad(index->is_primary()); + ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX + | MTR_MEMO_PAGE_S_FIX)); + ut_ad(!rw_lock_own(&(purge_sys.latch), RW_LOCK_S)); + + ut_ad(rec_offs_validate(rec, index, *offsets)); + + trx_id = row_get_rec_trx_id(rec, index, *offsets); + + ut_ad(!view->changes_visible(trx_id, index->table->name)); + + ut_ad(!vrow || !(*vrow)); + + version = rec; + + for (;;) { + mem_heap_t* prev_heap = heap; + + heap = mem_heap_create(1024); + + if (vrow) { + *vrow = NULL; + } + + /* If purge can't see the record then we can't rely on + the UNDO log record. */ + + bool purge_sees = trx_undo_prev_version_build( + rec, mtr, version, index, *offsets, heap, + &prev_version, NULL, vrow, 0); + + err = (purge_sees) ? DB_SUCCESS : DB_MISSING_HISTORY; + + if (prev_heap != NULL) { + mem_heap_free(prev_heap); + } + + if (prev_version == NULL) { + /* It was a freshly inserted version */ + *old_vers = NULL; + ut_ad(!vrow || !(*vrow)); + break; + } + + *offsets = rec_get_offsets( + prev_version, index, *offsets, + index->n_core_fields, 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 (view->changes_visible(trx_id, index->table->name)) { + + /* The view already sees this version: we can copy + it to in_heap and return */ + + buf = static_cast<byte*>( + mem_heap_alloc( + in_heap, rec_offs_size(*offsets))); + + *old_vers = rec_copy(buf, prev_version, *offsets); + rec_offs_make_valid(*old_vers, index, true, *offsets); + + if (vrow && *vrow) { + *vrow = dtuple_copy(*vrow, in_heap); + dtuple_dup_v_fld(*vrow, in_heap); + } + break; + } + + version = prev_version; + } + + mem_heap_free(heap); + + return(err); +} + +/*****************************************************************//** +Constructs the last committed version of a clustered index record, +which should be seen by a semi-consistent read. */ +void +row_vers_build_for_semi_consistent_read( +/*====================================*/ + trx_t* caller_trx,/*!<in/out: trx of current thread */ + 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 */ + rec_offs** offsets,/*!< in/out: offsets returned by + rec_get_offsets(rec, index) */ + 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 */ + const rec_t** old_vers,/*!< out: rec, old version, or NULL if the + record does not exist in the view, that is, + it was freshly inserted afterwards */ + dtuple_t** vrow) /*!< out: virtual row, old version, or NULL + if it is not updated in the view */ +{ + const rec_t* version; + mem_heap_t* heap = NULL; + byte* buf; + trx_id_t rec_trx_id = 0; + + ut_ad(index->is_primary()); + ut_ad(mtr->memo_contains_page_flagged(rec, MTR_MEMO_PAGE_X_FIX + | MTR_MEMO_PAGE_S_FIX)); + ut_ad(!rw_lock_own(&(purge_sys.latch), RW_LOCK_S)); + + ut_ad(rec_offs_validate(rec, index, *offsets)); + + version = rec; + ut_ad(!vrow || !(*vrow)); + + for (;;) { + mem_heap_t* heap2; + rec_t* prev_version; + trx_id_t version_trx_id; + + version_trx_id = row_get_rec_trx_id(version, index, *offsets); + if (rec == version) { + rec_trx_id = version_trx_id; + } + + if (!trx_sys.is_registered(caller_trx, version_trx_id)) { +committed_version_trx: + /* We found a version that belongs to a + committed transaction: return it. */ + +#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 */ + + if (rec == version) { + *old_vers = rec; + if (vrow) { + *vrow = NULL; + } + break; + } + + /* We assume that a rolled-back transaction stays in + TRX_STATE_ACTIVE state until all the changes have been + rolled back and the transaction is removed from + the global list of transactions. */ + + if (rec_trx_id == version_trx_id) { + /* The transaction was committed while + we searched for earlier versions. + Return the current version as a + semi-consistent read. */ + + version = rec; + *offsets = rec_get_offsets( + version, index, *offsets, + index->n_core_fields, ULINT_UNDEFINED, + offset_heap); + } + + buf = static_cast<byte*>( + mem_heap_alloc( + in_heap, rec_offs_size(*offsets))); + + *old_vers = rec_copy(buf, version, *offsets); + rec_offs_make_valid(*old_vers, index, true, *offsets); + if (vrow && *vrow) { + *vrow = dtuple_copy(*vrow, in_heap); + dtuple_dup_v_fld(*vrow, in_heap); + } + break; + } + + DEBUG_SYNC_C("after_row_vers_check_trx_active"); + + heap2 = heap; + heap = mem_heap_create(1024); + + if (!trx_undo_prev_version_build(rec, mtr, version, index, + *offsets, heap, + &prev_version, + in_heap, vrow, 0)) { + mem_heap_free(heap); + heap = heap2; + heap2 = NULL; + goto committed_version_trx; + } + + if (heap2) { + mem_heap_free(heap2); /* free version */ + } + + if (prev_version == NULL) { + /* It was a freshly inserted version */ + *old_vers = NULL; + ut_ad(!vrow || !(*vrow)); + break; + } + + version = prev_version; + *offsets = rec_get_offsets(version, index, *offsets, + index->n_core_fields, + ULINT_UNDEFINED, offset_heap); +#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 */ + }/* for (;;) */ + + if (heap) { + mem_heap_free(heap); + } +} |