/***************************************************************************** Copyright (c) 1996, 2019, Oracle and/or its affiliates. All Rights Reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2.0, as published by the Free Software Foundation. This program is also distributed with certain software (including but not limited to OpenSSL) that is licensed under separate terms, as designated in a particular file or component or in included license documentation. The authors of MySQL hereby grant you an additional permission to link the program and your derivative works with the separately licensed software that they have included with MySQL. 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, version 2.0, 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 St, Fifth Floor, Boston, MA 02110-1301 USA *****************************************************************************/ /** @file include/trx0rec.h Transaction undo log record Created 3/26/1996 Heikki Tuuri *******************************************************/ #ifndef trx0rec_h #define trx0rec_h #include "univ.i" #include "data0data.h" #include "dict0types.h" #include "lob0undo.h" #include "mtr0mtr.h" #include "page0types.h" #include "rem0types.h" #include "row0log.h" #include "row0types.h" #include "trx0types.h" #ifndef UNIV_HOTBACKUP #include "que0types.h" #include "lizard0undo0types.h" #include "lizard0read0types.h" /** Copies the undo record to the heap. @param[in] undo_rec undo log record @param[in] heap heap where copied @return own: copy of undo log record */ UNIV_INLINE trx_undo_rec_t *trx_undo_rec_copy(const trx_undo_rec_t *undo_rec, mem_heap_t *heap); /** Reads the undo log record type. @return record type */ UNIV_INLINE ulint trx_undo_rec_get_type( const trx_undo_rec_t *undo_rec); /*!< in: undo log record */ /** Reads from an undo log record the record compiler info. @return compiler info */ UNIV_INLINE ulint trx_undo_rec_get_cmpl_info( const trx_undo_rec_t *undo_rec); /*!< in: undo log record */ /** Returns TRUE if an undo log record contains an extern storage field. @return true if extern */ UNIV_INLINE ibool trx_undo_rec_get_extern_storage( const trx_undo_rec_t *undo_rec); /*!< in: undo log record */ /** Reads the undo log record number. @return undo no */ UNIV_INLINE undo_no_t trx_undo_rec_get_undo_no( const trx_undo_rec_t *undo_rec); /*!< in: undo log record */ /** Returns the start of the undo record data area. */ #define trx_undo_rec_get_ptr(undo_rec, undo_no) \ ((undo_rec) + trx_undo_rec_get_offset(undo_no)) /** Reads from an undo log record the table ID @param[in] undo_rec Undo log record @return the table ID */ table_id_t trx_undo_rec_get_table_id(const trx_undo_rec_t *undo_rec) MY_ATTRIBUTE((warn_unused_result)); /** Builds a row reference from an undo log record. @return pointer to remaining part of undo record */ byte *trx_undo_rec_get_row_ref( byte *ptr, /*!< in: remaining part of a copy of an undo log record, at the start of the row reference; NOTE that this copy of the undo log record must be preserved as long as the row reference is used, as we do NOT copy the data in the record! */ dict_index_t *index, /*!< in: clustered index */ dtuple_t **ref, /*!< out, own: row reference */ mem_heap_t *heap); /*!< in: memory heap from which the memory needed is allocated */ /** Reads from an undo log update record the system field values of the old version. @return remaining part of undo log record after reading these values */ byte *trx_undo_update_rec_get_sys_cols( const byte *ptr, /*!< in: remaining part of undo log record after reading general parameters */ trx_id_t *trx_id, /*!< out: trx id */ roll_ptr_t *roll_ptr, /*!< out: roll ptr */ ulint *info_bits); /*!< out: info bits state */ struct type_cmpl_t; /** Builds an update vector based on a remaining part of an undo log record. @return remaining part of the record, NULL if an error detected, which means that the record is corrupted. */ byte *trx_undo_update_rec_get_update( const byte *ptr, /*!< in: remaining part in update undo log record, after reading the row reference NOTE that this copy of the undo log record must be preserved as long as the update vector is used, as we do NOT copy the data in the record! */ const dict_index_t *index, /*!< in: clustered index */ ulint type, /*!< in: TRX_UNDO_UPD_EXIST_REC, TRX_UNDO_UPD_DEL_REC, or TRX_UNDO_DEL_MARK_REC; in the last case, only trx id and roll ptr fields are added to the update vector */ trx_id_t trx_id, /*!< in: transaction id from this undo record */ roll_ptr_t roll_ptr, /*!< in: roll pointer from this undo record */ ulint info_bits, /*!< in: info bits from this undo record */ trx_t *trx, /*!< in: transaction */ mem_heap_t *heap, /*!< in: memory heap from which the memory needed is allocated */ upd_t **upd, /*!< out, own: update vector */ lob::undo_vers_t *lob_undo, /*!< out: LOB undo information. */ type_cmpl_t &type_cmpl, /*!< out: type compilation info */ txn_info_t txn_info); /*!< in: txn information */ /** Builds a partial row from an update undo log record, for purge. It contains the columns which occur as ordering in any index of the table. Any missing columns are indicated by col->mtype == DATA_MISSING. @return pointer to remaining part of undo record */ byte *trx_undo_rec_get_partial_row( const byte *ptr, /*!< in: remaining part in update undo log record of a suitable type, at the start of the stored index columns; NOTE that this copy of the undo log record must be preserved as long as the partial row is used, as we do NOT copy the data in the record! */ dict_index_t *index, /*!< in: clustered index */ dtuple_t **row, /*!< out, own: partial row */ ibool ignore_prefix, /*!< in: flag to indicate if we expect blob prefixes in undo. Used only in the assertion. */ mem_heap_t *heap) /*!< in: memory heap from which the memory needed is allocated */ MY_ATTRIBUTE((warn_unused_result)); /** Writes information to an undo log about an insert, update, or a delete marking of a clustered index record. This information is used in a rollback of the transaction and in consistent reads that must look to the history of this transaction. @return DB_SUCCESS or error code */ dberr_t trx_undo_report_row_operation( ulint flags, /*!< in: if BTR_NO_UNDO_LOG_FLAG bit is set, does nothing */ ulint op_type, /*!< in: TRX_UNDO_INSERT_OP or TRX_UNDO_MODIFY_OP */ que_thr_t *thr, /*!< in: query thread */ dict_index_t *index, /*!< in: clustered index */ const dtuple_t *clust_entry, /*!< in: in the case of an insert, index entry to insert into the clustered index, otherwise NULL */ const upd_t *update, /*!< in: in the case of an update, the update vector, otherwise NULL */ ulint cmpl_info, /*!< in: compiler info on secondary index updates */ const rec_t *rec, /*!< in: case of an update or delete marking, the record in the clustered index, otherwise NULL */ const ulint *offsets, /*!< in: rec_get_offsets(rec) */ roll_ptr_t *roll_ptr) /*!< out: rollback pointer to the inserted undo log record, 0 if BTR_NO_UNDO_LOG flag was specified */ MY_ATTRIBUTE((warn_unused_result)); /** status bit used for trx_undo_prev_version_build() */ /** TRX_UNDO_PREV_IN_PURGE tells trx_undo_prev_version_build() that it is being called purge view and we would like to get the purge record even it is in the purge view (in normal case, it will return without fetching the purge record */ #define TRX_UNDO_PREV_IN_PURGE 0x1 /** This tells trx_undo_prev_version_build() to fetch the old value in the undo log (which is the after image for an update) */ #define TRX_UNDO_GET_OLD_V_VALUE 0x2 /** Build a previous version of a clustered index record. The caller must hold a latch on the index page of the clustered index record. If the vrow passed to this function is not null, then this function will store information about virtual columns from the requested version in vrow, unless the change did not affect any secondary index nor ordering field of clustered index (the change has UPD_NODE_NO_ORD_CHANGE flag) in which case the requested information can not be reconstructed from undo log, and the caller may assume that the (virtual) columns of secondary index have the same values they have in the more recent version (the one `rec` comes from). Equivalently, if the vrow is not returned, it is either because it was not requested, or not available due to UPD_NODE_NO_ORD_CHANGE. Obviously vrow is also not set in case rec is the oldest version in history, in which case we also set old_vers to NULL. @param[in] index_rec clustered index record in the index tree @param[in] index_mtr mtr which contains the latch to index_rec page and purge_view @param[in] rec version of a clustered index record @param[in] index clustered index @param[in,out] offsets rec_get_offsets(rec, index) @param[in] heap memory heap from which the memory needed is allocated @param[out] old_vers previous version, or NULL if rec is the first inserted version, or if history data has been deleted @param[in] v_heap memory heap used to create vrow dtuple if it is not yet created. This heap diffs from "heap" above in that it could be prebuilt->old_vers_heap for selection @param[out] vrow virtual column info, if any @param[in] v_status status determine if it is going into this function by purge thread or not. And if we read "after image" of undo log has been rebuilt @param[in] lob_undo LOB undo information. @param[in] vision vision used by as-of query. (lizard) @retval true if previous version was built, or if it was an insert or the table has been rebuilt @retval false if the previous version is earlier than purge_view, or being purged, which means that it may have been removed */ bool trx_undo_prev_version_build(const rec_t *index_rec, mtr_t *index_mtr, const rec_t *rec, const dict_index_t *index, ulint *offsets, mem_heap_t *heap, rec_t **old_vers, mem_heap_t *v_heap, const dtuple_t **vrow, ulint v_status, lob::undo_vers_t *lob_undo, const lizard::Vision *vision); #endif /* !UNIV_HOTBACKUP */ /** Parses a redo log record of adding an undo log record. @return end of log record or NULL */ byte *trx_undo_parse_add_undo_rec(byte *ptr, /*!< in: buffer */ byte *end_ptr, /*!< in: buffer end */ page_t *page); /*!< in: page or NULL */ /** Parses a redo log record of erasing of an undo page end. @return end of log record or NULL */ byte *trx_undo_parse_erase_page_end(byte *ptr, /*!< in: buffer */ byte *end_ptr, /*!< in: buffer end */ page_t *page, /*!< in: page or NULL */ mtr_t *mtr); /*!< in: mtr or NULL */ /** Read from an undo log record a non-virtual column value. @param[in,out] ptr pointer to remaining part of the undo record @param[in,out] field stored field @param[in,out] len length of the field, or UNIV_SQL_NULL @param[in,out] orig_len original length of the locally stored part of an externally stored column, or 0 @return remaining part of undo log record after reading these values */ byte *trx_undo_rec_get_col_val(const byte *ptr, const byte **field, ulint *len, ulint *orig_len); /** Read virtual column value from undo log @param[in] table the table @param[in] ptr undo log pointer @param[in,out] row the dtuple to fill @param[in] in_purge called by purge thread @param[in] online true if this is from online DDL log @param[in] col_map online rebuild column map @param[in,out] heap memory heap to keep value when necessary */ void trx_undo_read_v_cols(const dict_table_t *table, const byte *ptr, const dtuple_t *row, bool in_purge, bool online, const ulint *col_map, mem_heap_t *heap); /** Read virtual column index from undo log if the undo log contains such info, and verify the column is still indexed, and output its position @param[in] table the table @param[in] ptr undo log pointer @param[in] first_v_col if this is the first virtual column, which has the version marker @param[in,out] is_undo_log his function is used to parse both undo log, and online log for virtual columns. So check to see if this is undo log @param[out] field_no the column number @return remaining part of undo log record after reading these values */ const byte *trx_undo_read_v_idx(const dict_table_t *table, const byte *ptr, bool first_v_col, bool *is_undo_log, ulint *field_no); #ifndef UNIV_HOTBACKUP /* Types of an undo log record: these have to be smaller than 16, as the compilation info multiplied by 16 is ORed to this value in an undo log record */ #define TRX_UNDO_INSERT_REC 11 /* fresh insert into clustered index */ #define TRX_UNDO_UPD_EXIST_REC \ 12 /* update of a non-delete-marked \ record */ #define TRX_UNDO_UPD_DEL_REC \ 13 /* update of a delete marked record to \ a not delete marked record; also the \ fields of the record can change */ #define TRX_UNDO_DEL_MARK_REC \ 14 /* delete marking of a record; fields \ do not change */ #define TRX_UNDO_CMPL_INFO_MULT \ 16 /* compilation info is multiplied by \ this and ORed to the type above */ #define TRX_UNDO_MODIFY_BLOB \ 64 /* If this bit is set in type_cmpl, \ then the undo log record has support \ for partial update of BLOBs. Also to \ make the undo log format extensible, \ introducing a new flag next to the \ type_cmpl flag. */ #define TRX_UNDO_UPD_EXTERN \ 128 /* This bit can be ORed to type_cmpl \ to denote that we updated external \ storage fields: used by purge to \ free the external storage */ /* Operation type flags used in trx_undo_report_row_operation */ #define TRX_UNDO_INSERT_OP 1 #define TRX_UNDO_MODIFY_OP 2 /** The type and compilation info flag in the undo record for update. For easier understanding let the 8 bits be numbered as 7, 6, 5, 4, 3, 2, 1, 0. */ struct type_cmpl_t { type_cmpl_t() : m_flag(0) {} const byte *read(const byte *ptr) { m_flag = mach_read_from_1(ptr); return (ptr + 1); } ulint type_info() { /* Get 0-3 */ return (m_flag & 0x0F); } ulint cmpl_info() { /* Get bits 5 and 4 */ return ((m_flag >> 4) & 0x03); } /** Is an LOB updated by this update operation. @return true if LOB is updated, false otherwise. */ bool is_lob_updated() { /* Check if bit 7 is set. */ return (m_flag & TRX_UNDO_UPD_EXTERN); } /** Does the undo log record contains information about LOB partial update vector. @return true if undo contains LOB update info. */ bool is_lob_undo() const { /* Check if bit 6 is set. */ return (m_flag & TRX_UNDO_MODIFY_BLOB); } private: uint8_t m_flag; }; /** Reads from an undo log record the general parameters. @return remaining part of undo log record after reading these values */ byte *trx_undo_rec_get_pars( trx_undo_rec_t *undo_rec, /*!< in: undo log record */ ulint *type, /*!< out: undo record type: TRX_UNDO_INSERT_REC, ... */ ulint *cmpl_info, /*!< out: compiler info, relevant only for update type records */ bool *updated_extern, /*!< out: true if we updated an externally stored fild */ undo_no_t *undo_no, /*!< out: undo log record number */ table_id_t *table_id, /*!< out: table id */ type_cmpl_t &type_cmpl); /*!< out: type compilation info. */ /** Get the max free space of undo log by assuming it's a fresh new page and the free space doesn't count for the undo log header too. */ size_t trx_undo_max_free_space(); /** Decide if the following undo log record is a multi-value virtual column @param[in] undo_rec undo log record @return true if this is a multi-value virtual column log, otherwise false */ bool trx_undo_rec_is_multi_value(const byte *undo_rec); /** Read from an undo log record a non-virtual column value. @param[in,out] ptr pointer to remaining part of the undo record @param[in,out] field stored field @param[in,out] heap memory heap @return remaining part of undo log record after reading these values */ const byte *trx_undo_rec_get_multi_value(const byte *ptr, dfield_t *field, mem_heap_t *heap); #include "trx0rec.ic" #endif /* !UNIV_HOTBACKUP */ #endif /* trx0rec_h */