diff options
Diffstat (limited to 'storage/innobase/trx/trx0undo.cc')
| -rw-r--r-- | storage/innobase/trx/trx0undo.cc | 1581 |
1 files changed, 1581 insertions, 0 deletions
diff --git a/storage/innobase/trx/trx0undo.cc b/storage/innobase/trx/trx0undo.cc new file mode 100644 index 00000000..cd21ebe1 --- /dev/null +++ b/storage/innobase/trx/trx0undo.cc @@ -0,0 +1,1581 @@ +/***************************************************************************** + +Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved. +Copyright (c) 2014, 2022, 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 trx/trx0undo.cc +Transaction undo log + +Created 3/26/1996 Heikki Tuuri +*******************************************************/ + +#include "trx0undo.h" +#include "fsp0fsp.h" +#include "mach0data.h" +#include "mtr0log.h" +#include "srv0mon.h" +#include "srv0srv.h" +#include "srv0start.h" +#include "trx0purge.h" +#include "trx0rec.h" +#include "trx0rseg.h" +#include "log.h" + +/* How should the old versions in the history list be managed? + ---------------------------------------------------------- +If each transaction is given a whole page for its update undo log, file +space consumption can be 10 times higher than necessary. Therefore, +partly filled update undo log pages should be reusable. But then there +is no way individual pages can be ordered so that the ordering agrees +with the serialization numbers of the transactions on the pages. Thus, +the history list must be formed of undo logs, not their header pages as +it was in the old implementation. + However, on a single header page the transactions are placed in +the order of their serialization numbers. As old versions are purged, we +may free the page when the last transaction on the page has been purged. + A problem is that the purge has to go through the transactions +in the serialization order. This means that we have to look through all +rollback segments for the one that has the smallest transaction number +in its history list. + When should we do a purge? A purge is necessary when space is +running out in any of the rollback segments. Then we may have to purge +also old version which might be needed by some consistent read. How do +we trigger the start of a purge? When a transaction writes to an undo log, +it may notice that the space is running out. When a read view is closed, +it may make some history superfluous. The server can have an utility which +periodically checks if it can purge some history. + In a parallellized purge we have the problem that a query thread +can remove a delete marked clustered index record before another query +thread has processed an earlier version of the record, which cannot then +be done because the row cannot be constructed from the clustered index +record. To avoid this problem, we will store in the update and delete mark +undo record also the columns necessary to construct the secondary index +entries which are modified. + We can latch the stack of versions of a single clustered index record +by taking a latch on the clustered index page. As long as the latch is held, +no new versions can be added and no versions removed by undo. But, a purge +can still remove old versions from the bottom of the stack. */ + +/* How to protect rollback segments, undo logs, and history lists with + ------------------------------------------------------------------- +latches? +------- +When a transaction does its first insert or modify in the clustered index, an +undo log is assigned for it. Then we must have an x-latch to the rollback +segment header. + When the transaction performs modifications or rolls back, its +undo log is protected by undo page latches. +Only the thread that is associated with the transaction may hold multiple +undo page latches at a time. Undo pages are always private to a single +transaction. Other threads that are performing MVCC reads +or checking for implicit locks will lock at most one undo page at a time +in trx_undo_get_undo_rec_low(). + When the transaction commits, its persistent undo log is added +to the history list. If it is not suitable for reuse, its slot is reset. +In both cases, an x-latch must be acquired on the rollback segment header page. + The purge operation steps through the history list without modifying +it until a truncate operation occurs, which can remove undo logs from the end +of the list and release undo log segments. In stepping through the list, +s-latches on the undo log pages are enough, but in a truncate, x-latches must +be obtained on the rollback segment and individual pages. */ + +/********************************************************************//** +Creates and initializes an undo log memory object. +@return own: the undo log memory object */ +static +trx_undo_t* +trx_undo_mem_create( +/*================*/ + trx_rseg_t* rseg, /*!< in: rollback segment memory object */ + ulint id, /*!< in: slot index within rseg */ + trx_id_t trx_id, /*!< in: id of the trx for which the undo log + is created */ + const XID* xid, /*!< in: X/Open XA transaction identification*/ + uint32_t page_no,/*!< in: undo log header page number */ + uint16_t offset);/*!< in: undo log header byte offset on page */ + +/** Determine the start offset of undo log records of an undo log page. +@param[in] block undo log page +@param[in] page_no undo log header page number +@param[in] offset undo log header offset +@return start offset */ +static +uint16_t trx_undo_page_get_start(const buf_block_t *block, uint32_t page_no, + uint16_t offset) +{ + return page_no == block->page.id().page_no() + ? mach_read_from_2(offset + TRX_UNDO_LOG_START + block->page.frame) + : TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_HDR_SIZE; +} + +/** Get the first undo log record on a page. +@param[in] block undo log page +@param[in] page_no undo log header page number +@param[in] offset undo log header page offset +@return pointer to first record +@retval NULL if none exists */ +static trx_undo_rec_t* +trx_undo_page_get_first_rec(const buf_block_t *block, uint32_t page_no, + uint16_t offset) +{ + uint16_t start= trx_undo_page_get_start(block, page_no, offset); + return start == trx_undo_page_get_end(block, page_no, offset) + ? nullptr : block->page.frame + start; +} + +/** Get the last undo log record on a page. +@param[in] page undo log page +@param[in] page_no undo log header page number +@param[in] offset undo log header page offset +@return pointer to last record +@retval NULL if none exists */ +static +trx_undo_rec_t* +trx_undo_page_get_last_rec(const buf_block_t *block, uint32_t page_no, + uint16_t offset) +{ + uint16_t end= trx_undo_page_get_end(block, page_no, offset); + return trx_undo_page_get_start(block, page_no, offset) == end + ? nullptr + : block->page.frame + mach_read_from_2(block->page.frame + end - 2); +} + +/** Get the previous record in an undo log from the previous page. +@param[in,out] block undo log page +@param[in] rec undo record offset in the page +@param[in] page_no undo log header page number +@param[in] offset undo log header offset on page +@param[in] shared latching mode: true=RW_S_LATCH, false=RW_X_LATCH +@param[in,out] mtr mini-transaction +@return undo log record, the page latched, NULL if none */ +static trx_undo_rec_t* +trx_undo_get_prev_rec_from_prev_page(buf_block_t *&block, uint16_t rec, + uint32_t page_no, uint16_t offset, + bool shared, mtr_t *mtr) +{ + uint32_t prev_page_no= mach_read_from_4(TRX_UNDO_PAGE_HDR + + TRX_UNDO_PAGE_NODE + + FLST_PREV + FIL_ADDR_PAGE + + block->page.frame); + + if (prev_page_no == FIL_NULL) + return nullptr; + + block= buf_page_get(page_id_t(block->page.id().space(), prev_page_no), + 0, shared ? RW_S_LATCH : RW_X_LATCH, mtr); + + return block ? trx_undo_page_get_last_rec(block, page_no, offset) : nullptr; +} + +/** Get the previous undo log record. +@param[in] block undo log page +@param[in] rec undo log record +@param[in] page_no undo log header page number +@param[in] offset undo log header page offset +@return pointer to record +@retval NULL if none */ +static +trx_undo_rec_t* +trx_undo_page_get_prev_rec(const buf_block_t *block, trx_undo_rec_t *rec, + uint32_t page_no, uint16_t offset) +{ + ut_ad(block->page.frame == page_align(rec)); + return + rec == block->page.frame + trx_undo_page_get_start(block, page_no, offset) + ? nullptr + : block->page.frame + mach_read_from_2(rec - 2); +} + +/** Get the previous record in an undo log. +@param[in,out] block undo log page +@param[in] rec undo record offset in the page +@param[in] page_no undo log header page number +@param[in] offset undo log header offset on page +@param[in] shared latching mode: true=RW_S_LATCH, false=RW_X_LATCH +@param[in,out] mtr mini-transaction +@return undo log record, the page latched, NULL if none */ +trx_undo_rec_t* +trx_undo_get_prev_rec(buf_block_t *&block, uint16_t rec, uint32_t page_no, + uint16_t offset, bool shared, mtr_t *mtr) +{ + if (trx_undo_rec_t *prev= trx_undo_page_get_prev_rec(block, + block->page.frame + rec, + page_no, offset)) + return prev; + + /* We have to go to the previous undo log page to look for the + previous record */ + + return trx_undo_get_prev_rec_from_prev_page(block, rec, page_no, offset, + shared, mtr); +} + +/** Get the next record in an undo log from the next page. +@param[in,out] block undo log page +@param[in] page_no undo log header page number +@param[in] offset undo log header offset on page +@param[in] mode latching mode: RW_S_LATCH or RW_X_LATCH +@param[in,out] mtr mini-transaction +@return undo log record, the page latched, NULL if none */ +static trx_undo_rec_t* +trx_undo_get_next_rec_from_next_page(const buf_block_t *&block, + uint32_t page_no, uint16_t offset, + ulint mode, mtr_t *mtr) +{ + if (page_no == block->page.id().page_no() && + mach_read_from_2(block->page.frame + offset + TRX_UNDO_NEXT_LOG)) + return nullptr; + + uint32_t next= mach_read_from_4(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + + FLST_NEXT + FIL_ADDR_PAGE + + block->page.frame); + if (next == FIL_NULL) + return nullptr; + + block= buf_page_get_gen(page_id_t(block->page.id().space(), next), 0, mode, + nullptr, BUF_GET_POSSIBLY_FREED, mtr); + + return block ? trx_undo_page_get_first_rec(block, page_no, offset) : nullptr; +} + +/** Get the next record in an undo log. +@param[in,out] block undo log page +@param[in] rec undo record offset in the page +@param[in] page_no undo log header page number +@param[in] offset undo log header offset on page +@param[in,out] mtr mini-transaction +@return undo log record, the page latched, NULL if none */ +trx_undo_rec_t* +trx_undo_get_next_rec(const buf_block_t *&block, uint16_t rec, + uint32_t page_no, uint16_t offset, mtr_t *mtr) +{ + if (trx_undo_rec_t *next= trx_undo_page_get_next_rec(block, rec, page_no, + offset)) + return next; + + return trx_undo_get_next_rec_from_next_page(block, page_no, offset, + RW_S_LATCH, mtr); +} + +/** Get the first record in an undo log. +@param[in] space undo log header space +@param[in] page_no undo log header page number +@param[in] offset undo log header offset on page +@param[in] mode latching mode: RW_S_LATCH or RW_X_LATCH +@param[out] block undo log page +@param[in,out] mtr mini-transaction +@param[out] err error code +@return undo log record, the page latched +@retval nullptr if none */ +trx_undo_rec_t* +trx_undo_get_first_rec(const fil_space_t &space, uint32_t page_no, + uint16_t offset, ulint mode, const buf_block_t*& block, + mtr_t *mtr, dberr_t *err) +{ + block= buf_page_get_gen(page_id_t{space.id, page_no}, 0, mode, + nullptr, BUF_GET, mtr, err); + if (!block) + return nullptr; + + if (trx_undo_rec_t *rec= trx_undo_page_get_first_rec(block, page_no, offset)) + return rec; + + return trx_undo_get_next_rec_from_next_page(block, page_no, offset, mode, + mtr); +} + +inline void UndorecApplier::assign_rec(const buf_block_t &block, + uint16_t offset) +{ + ut_ad(block.page.lock.have_s()); + this->offset= offset; + this->undo_rec= trx_undo_rec_copy(block.page.frame + offset, heap); +} + +inline void UndorecApplier::apply_undo_rec() +{ + if (!undo_rec) + return; + bool updated_extern= false; + undo_no_t undo_no= 0; + table_id_t table_id= 0; + undo_rec= trx_undo_rec_get_pars(undo_rec, &type, + &cmpl_info, + &updated_extern, &undo_no, &table_id); + dict_sys.freeze(SRW_LOCK_CALL); + dict_table_t *table= dict_sys.find_table(table_id); + dict_sys.unfreeze(); + + ut_ad(table); + if (!table->is_active_ddl()) + return; + + dict_index_t *index= dict_table_get_first_index(table); + const dtuple_t *undo_tuple; + switch (type) { + default: + ut_ad("invalid type" == 0); + MY_ASSERT_UNREACHABLE(); + case TRX_UNDO_INSERT_REC: + undo_rec= trx_undo_rec_get_row_ref(undo_rec, index, &undo_tuple, heap); + insert: + log_insert(*undo_tuple, index); + break; + case TRX_UNDO_UPD_EXIST_REC: + case TRX_UNDO_UPD_DEL_REC: + case TRX_UNDO_DEL_MARK_REC: + trx_id_t trx_id; + roll_ptr_t roll_ptr; + byte info_bits; + undo_rec= trx_undo_update_rec_get_sys_cols( + undo_rec, &trx_id, &roll_ptr, &info_bits); + + undo_rec= trx_undo_rec_get_row_ref(undo_rec, index, &undo_tuple, heap); + undo_rec= trx_undo_update_rec_get_update(undo_rec, index, type, trx_id, + roll_ptr, info_bits, + heap, &update); + if (type == TRX_UNDO_UPD_DEL_REC) + goto insert; + log_update(*undo_tuple, index); + } + + clear_undo_rec(); +} + +/** Apply any changes to tables for which online DDL is in progress. */ +ATTRIBUTE_COLD void trx_t::apply_log() +{ + const trx_undo_t *undo= rsegs.m_redo.undo; + if (!undo || !undo_no) + return; + page_id_t page_id{rsegs.m_redo.rseg->space->id, undo->hdr_page_no}; + page_id_t next_page_id(page_id); + mtr_t mtr; + mtr.start(); + buf_block_t *block= buf_page_get(page_id, 0, RW_S_LATCH, &mtr); + if (UNIV_UNLIKELY(!block)) + { + mtr.commit(); + return; + } + + UndorecApplier log_applier(page_id, id); + + for (;;) + { + trx_undo_rec_t *rec= trx_undo_page_get_first_rec(block, page_id.page_no(), + undo->hdr_offset); + while (rec) + { + log_applier.assign_rec(*block, page_offset(rec)); + mtr.commit(); + log_applier.apply_undo_rec(); + mtr.start(); + block= buf_page_get(log_applier.get_page_id(), 0, RW_S_LATCH, &mtr); + if (UNIV_UNLIKELY(!block)) + goto func_exit; + rec= trx_undo_page_get_next_rec(block, log_applier.get_offset(), + page_id.page_no(), undo->hdr_offset); + } + + uint32_t next= mach_read_from_4(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + + FLST_NEXT + FIL_ADDR_PAGE + + block->page.frame); + if (next == FIL_NULL) + break; + next_page_id.set_page_no(next); + mtr.commit(); + mtr.start(); + block= buf_page_get_gen(next_page_id, 0, RW_S_LATCH, block, BUF_GET, &mtr); + if (UNIV_UNLIKELY(!block)) + break; + log_applier.assign_next(next_page_id); + } +func_exit: + mtr.commit(); + apply_online_log= false; +} + +/*============== UNDO LOG FILE COPY CREATION AND FREEING ==================*/ + +/** Initialize an undo log page. +NOTE: This corresponds to a redo log record and must not be changed! +@see mtr_t::undo_create() +@param block undo log page */ +void trx_undo_page_init(const buf_block_t &block) +{ + mach_write_to_2(my_assume_aligned<2>(FIL_PAGE_TYPE + block.page.frame), + FIL_PAGE_UNDO_LOG); + static_assert(TRX_UNDO_PAGE_HDR == FIL_PAGE_DATA, "compatibility"); + memset_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_TYPE + block.page.frame, + 0, 2); + mach_write_to_2(my_assume_aligned<2> + (TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START + block.page.frame), + TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_HDR_SIZE); + memcpy_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_FREE + block.page.frame, + TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START + block.page.frame, + 2); + /* The following corresponds to flst_zero_both(), but without writing log. */ + memset_aligned<4>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + FLST_PREV + + FIL_ADDR_PAGE + block.page.frame, 0xff, 4); + memset_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + FLST_PREV + + FIL_ADDR_BYTE + block.page.frame, 0, 2); + memset_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + FLST_NEXT + + FIL_ADDR_PAGE + block.page.frame, 0xff, 4); + memset_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + FLST_NEXT + + FIL_ADDR_BYTE + block.page.frame, 0, 2); + static_assert(TRX_UNDO_PAGE_NODE + FLST_NEXT + FIL_ADDR_BYTE + 2 == + TRX_UNDO_PAGE_HDR_SIZE, "compatibility"); + /* Preserve TRX_UNDO_SEG_HDR, but clear the rest of the page. */ + memset_aligned<2>(TRX_UNDO_SEG_HDR + TRX_UNDO_SEG_HDR_SIZE + + block.page.frame, 0, + srv_page_size - (TRX_UNDO_SEG_HDR + TRX_UNDO_SEG_HDR_SIZE + + FIL_PAGE_DATA_END)); +} + +/** Look for a free slot for an undo log segment. +@param rseg_header rollback segment header +@return slot index +@retval ULINT_UNDEFINED if not found */ +static ulint trx_rsegf_undo_find_free(const buf_block_t *rseg_header) +{ + ulint max_slots= TRX_RSEG_N_SLOTS; + +#ifdef UNIV_DEBUG + if (trx_rseg_n_slots_debug) + max_slots= std::min<ulint>(trx_rseg_n_slots_debug, TRX_RSEG_N_SLOTS); +#endif + + for (ulint i= 0; i < max_slots; i++) + if (trx_rsegf_get_nth_undo(rseg_header, i) == FIL_NULL) + return i; + + return ULINT_UNDEFINED; +} + +/** Create an undo log segment. +@param[in,out] space tablespace +@param[in,out] rseg_hdr rollback segment header (x-latched) +@param[out] id undo slot number +@param[out] err error code +@param[in,out] mtr mini-transaction +@return undo log block +@retval NULL on failure */ +static MY_ATTRIBUTE((nonnull, warn_unused_result)) +buf_block_t* +trx_undo_seg_create(fil_space_t *space, buf_block_t *rseg_hdr, ulint *id, + dberr_t *err, mtr_t *mtr) +{ + buf_block_t* block; + uint32_t n_reserved; + + const ulint slot_no = trx_rsegf_undo_find_free(rseg_hdr); + + if (slot_no == ULINT_UNDEFINED) { + ib::warn() << "Cannot find a free slot for an undo log. Do" + " you have too many active transactions running" + " concurrently?"; + + *err = DB_TOO_MANY_CONCURRENT_TRXS; + return NULL; + } + + ut_ad(slot_no < TRX_RSEG_N_SLOTS); + + *err = fsp_reserve_free_extents(&n_reserved, space, 2, FSP_UNDO, + mtr); + if (UNIV_UNLIKELY(*err != DB_SUCCESS)) { + return NULL; + } + + /* Allocate a new file segment for the undo log */ + block = fseg_create(space, TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER, + mtr, err, true); + + space->release_free_extents(n_reserved); + + if (!block) { + return block; + } + + mtr->undo_create(*block); + trx_undo_page_init(*block); + + mtr->write<2>(*block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_FREE + + block->page.frame, + TRX_UNDO_SEG_HDR + TRX_UNDO_SEG_HDR_SIZE); + mtr->write<2,mtr_t::MAYBE_NOP>(*block, + TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG + + block->page.frame, 0U); + + flst_init(*block, TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST + + block->page.frame, mtr); + + *err = flst_add_last(block, TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST, + block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE, + mtr); + + *id = slot_no; + mtr->write<4>(*rseg_hdr, TRX_RSEG + TRX_RSEG_UNDO_SLOTS + + slot_no * TRX_RSEG_SLOT_SIZE + rseg_hdr->page.frame, + block->page.id().page_no()); + + MONITOR_INC(MONITOR_NUM_UNDO_SLOT_USED); + + *err = DB_SUCCESS; + return block; +} + +/** Initialize an undo log header. +@param[in,out] undo_page undo log segment header page +@param[in] trx_id transaction identifier +@param[in,out] mtr mini-transaction +@return header byte offset on page */ +static uint16_t trx_undo_header_create(buf_block_t *undo_page, trx_id_t trx_id, + mtr_t* mtr) +{ + /* Reset the TRX_UNDO_PAGE_TYPE in case this page is being + repurposed after upgrading to MariaDB 10.3. */ + byte *undo_type= my_assume_aligned<2> + (TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_TYPE + undo_page->page.frame); + ut_ad(mach_read_from_2(undo_type) <= 2); + mtr->write<2,mtr_t::MAYBE_NOP>(*undo_page, undo_type, 0U); + byte *start= my_assume_aligned<4>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START + + undo_page->page.frame); + const uint16_t free= mach_read_from_2(start + 2); + static_assert(TRX_UNDO_PAGE_START + 2 == TRX_UNDO_PAGE_FREE, + "compatibility"); + ut_a(free + TRX_UNDO_LOG_XA_HDR_SIZE < srv_page_size - 100); + + mach_write_to_2(start, free + TRX_UNDO_LOG_XA_HDR_SIZE); + /* A WRITE of 2 bytes is never longer than a MEMMOVE. + So, WRITE 2+2 bytes is better than WRITE+MEMMOVE. + But, a MEMSET will only be 1+2 bytes, that is, 1 byte shorter! */ + memcpy_aligned<2>(start + 2, start, 2); + mtr->memset(*undo_page, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START, 4, + start, 2); + uint16_t prev_log= mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG + + undo_page->page.frame); + alignas(4) byte buf[4]; + mach_write_to_2(buf, TRX_UNDO_ACTIVE); + mach_write_to_2(buf + 2, free); + static_assert(TRX_UNDO_STATE + 2 == TRX_UNDO_LAST_LOG, "compatibility"); + static_assert(!((TRX_UNDO_SEG_HDR + TRX_UNDO_STATE) % 4), "alignment"); + mtr->memcpy(*undo_page, my_assume_aligned<4> + (TRX_UNDO_SEG_HDR + TRX_UNDO_STATE + undo_page->page.frame), + buf, 4); + if (prev_log) + mtr->write<2>(*undo_page, prev_log + TRX_UNDO_NEXT_LOG + + undo_page->page.frame, free); + mtr->write<8,mtr_t::MAYBE_NOP>(*undo_page, free + TRX_UNDO_TRX_ID + + undo_page->page.frame, trx_id); + if (UNIV_UNLIKELY(mach_read_from_8(free + TRX_UNDO_TRX_NO + + undo_page->page.frame) != 0)) + mtr->memset(undo_page, free + TRX_UNDO_TRX_NO, 8, 0); + + /* Write TRX_UNDO_NEEDS_PURGE=1 and TRX_UNDO_LOG_START. */ + mach_write_to_2(buf, 1); + memcpy_aligned<2>(buf + 2, start, 2); + static_assert(TRX_UNDO_NEEDS_PURGE + 2 == TRX_UNDO_LOG_START, + "compatibility"); + mtr->memcpy<mtr_t::MAYBE_NOP>(*undo_page, free + TRX_UNDO_NEEDS_PURGE + + undo_page->page.frame, buf, 4); + /* Initialize all fields TRX_UNDO_XID_EXISTS to TRX_UNDO_HISTORY_NODE. */ + if (prev_log) + { + mtr->memset(undo_page, free + TRX_UNDO_XID_EXISTS, + TRX_UNDO_PREV_LOG - TRX_UNDO_XID_EXISTS, 0); + mtr->write<2,mtr_t::MAYBE_NOP>(*undo_page, free + TRX_UNDO_PREV_LOG + + undo_page->page.frame, prev_log); + static_assert(TRX_UNDO_PREV_LOG + 2 == TRX_UNDO_HISTORY_NODE, + "compatibility"); + mtr->memset(undo_page, free + TRX_UNDO_HISTORY_NODE, FLST_NODE_SIZE, 0); + static_assert(TRX_UNDO_LOG_OLD_HDR_SIZE == TRX_UNDO_HISTORY_NODE + + FLST_NODE_SIZE, "compatibility"); + } + else + mtr->memset(undo_page, free + TRX_UNDO_XID_EXISTS, + TRX_UNDO_LOG_OLD_HDR_SIZE - TRX_UNDO_XID_EXISTS, 0); + return free; +} + +/** Write X/Open XA Transaction Identifier (XID) to undo log header +@param[in,out] block undo header page +@param[in] offset undo header record offset +@param[in] xid distributed transaction identifier +@param[in,out] mtr mini-transaction */ +static void trx_undo_write_xid(buf_block_t *block, uint16_t offset, + const XID &xid, mtr_t *mtr) +{ + DBUG_ASSERT(xid.gtrid_length > 0); + DBUG_ASSERT(xid.bqual_length >= 0); + DBUG_ASSERT(xid.gtrid_length <= MAXGTRIDSIZE); + DBUG_ASSERT(xid.bqual_length <= MAXBQUALSIZE); + static_assert(MAXGTRIDSIZE + MAXBQUALSIZE == XIDDATASIZE, + "gtrid and bqual don't fit xid data"); + DBUG_ASSERT(mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG + + block->page.frame) == offset); + + trx_ulogf_t* log_hdr= block->page.frame + offset; + + mtr->write<4,mtr_t::MAYBE_NOP>(*block, log_hdr + TRX_UNDO_XA_FORMAT, + static_cast<uint32_t>(xid.formatID)); + mtr->write<4,mtr_t::MAYBE_NOP>(*block, log_hdr + TRX_UNDO_XA_TRID_LEN, + static_cast<uint32_t>(xid.gtrid_length)); + mtr->write<4,mtr_t::MAYBE_NOP>(*block, log_hdr + TRX_UNDO_XA_BQUAL_LEN, + static_cast<uint32_t>(xid.bqual_length)); + const ulint xid_length= static_cast<ulint>(xid.gtrid_length + + xid.bqual_length); + mtr->memcpy(*block, &block->page.frame[offset + TRX_UNDO_XA_XID], + xid.data, xid_length); + if (UNIV_LIKELY(xid_length < XIDDATASIZE)) + mtr->memset(block, offset + TRX_UNDO_XA_XID + xid_length, + XIDDATASIZE - xid_length, 0); +} + +/********************************************************************//** +Read X/Open XA Transaction Identification (XID) from undo log header */ +static +void +trx_undo_read_xid(const trx_ulogf_t* log_hdr, XID* xid) +{ + xid->formatID=static_cast<long>(mach_read_from_4( + log_hdr + TRX_UNDO_XA_FORMAT)); + + xid->gtrid_length=static_cast<long>(mach_read_from_4( + log_hdr + TRX_UNDO_XA_TRID_LEN)); + + xid->bqual_length=static_cast<long>(mach_read_from_4( + log_hdr + TRX_UNDO_XA_BQUAL_LEN)); + + memcpy(xid->data, log_hdr + TRX_UNDO_XA_XID, XIDDATASIZE); +} + +/** Allocate an undo log page. +@param[in,out] undo undo log +@param[in,out] mtr mini-transaction that does not hold any page latch +@param[out] err error code +@return X-latched block if success +@retval nullptr on failure */ +buf_block_t *trx_undo_add_page(trx_undo_t *undo, mtr_t *mtr, dberr_t *err) +{ + buf_block_t *new_block= nullptr; + uint32_t n_reserved; + + /* When we add a page to an undo log, this is analogous to + a pessimistic insert in a B-tree, and we must reserve the + counterpart of the tree latch, which is the rseg mutex. */ + + trx_rseg_t *rseg= undo->rseg; + rseg->latch.wr_lock(SRW_LOCK_CALL); + + buf_block_t *header_block= + buf_page_get_gen(page_id_t{rseg->space->id, undo->hdr_page_no}, + 0, RW_X_LATCH, nullptr, BUF_GET, mtr, err); + if (!header_block) + goto func_exit; + *err= fsp_reserve_free_extents(&n_reserved, rseg->space, 1, FSP_UNDO, mtr); + + if (UNIV_UNLIKELY(*err != DB_SUCCESS)) + goto func_exit; + + new_block= + fseg_alloc_free_page_general(TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER + + header_block->page.frame, + undo->top_page_no + 1, FSP_UP, true, + mtr, mtr, err); + rseg->space->release_free_extents(n_reserved); + + if (!new_block) + goto func_exit; + + undo->last_page_no= new_block->page.id().page_no(); + + mtr->undo_create(*new_block); + trx_undo_page_init(*new_block); + *err= flst_add_last(header_block, TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST, + new_block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE, mtr); + if (UNIV_UNLIKELY(*err != DB_SUCCESS)) + new_block= nullptr; + else + { + undo->size++; + rseg->curr_size++; + } + +func_exit: + rseg->latch.wr_unlock(); + return new_block; +} + +/********************************************************************//** +Frees an undo log page that is not the header page. +@return last page number in remaining log */ +static +uint32_t +trx_undo_free_page( +/*===============*/ + trx_rseg_t* rseg, /*!< in: rollback segment */ + bool in_history, /*!< in: TRUE if the undo log is in the history + list */ + uint32_t hdr_page_no, /*!< in: header page number */ + uint32_t page_no, /*!< in: page number to free: must not be the + header page */ + mtr_t* mtr, /*!< in: mtr which does not have a latch to any + undo log page; the caller must have reserved + the rollback segment mutex */ + dberr_t* err) /*!< out: error code */ +{ + ut_a(hdr_page_no != page_no); + + buf_block_t* undo_block = buf_page_get_gen(page_id_t(rseg->space->id, + page_no), + 0, RW_X_LATCH, nullptr, + BUF_GET, mtr, err); + if (UNIV_UNLIKELY(!undo_block)) { + return FIL_NULL; + } + buf_block_t* header_block = buf_page_get_gen(page_id_t(rseg->space->id, + hdr_page_no), + 0, RW_X_LATCH, nullptr, + BUF_GET, mtr, err); + if (UNIV_UNLIKELY(!header_block)) { + return FIL_NULL; + } + + *err = flst_remove(header_block, TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST, + undo_block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE, + mtr); + + if (UNIV_UNLIKELY(*err != DB_SUCCESS)) { + return FIL_NULL; + } + + *err = fseg_free_page(TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER + + header_block->page.frame, + rseg->space, page_no, mtr); + if (UNIV_UNLIKELY(*err != DB_SUCCESS)) { + return FIL_NULL; + } + buf_page_free(rseg->space, page_no, mtr); + + const fil_addr_t last_addr = flst_get_last( + TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST + + header_block->page.frame); + rseg->curr_size--; + + if (!in_history) { + } else if (buf_block_t* rseg_header = rseg->get(mtr, err)) { + byte* rseg_hist_size = TRX_RSEG + TRX_RSEG_HISTORY_SIZE + + rseg_header->page.frame; + uint32_t hist_size = mach_read_from_4(rseg_hist_size); + ut_ad(hist_size > 0); + mtr->write<4>(*rseg_header, rseg_hist_size, hist_size - 1); + } else { + return FIL_NULL; + } + + return(last_addr.page); +} + +/** Free the last undo log page. The caller must hold the rseg mutex. +@param[in,out] undo undo log +@param[in,out] mtr mini-transaction that does not hold any undo log page + or that has allocated the undo log page +@return error code */ +dberr_t trx_undo_free_last_page(trx_undo_t *undo, mtr_t *mtr) +{ + ut_ad(undo->hdr_page_no != undo->last_page_no); + ut_ad(undo->size > 0); + undo->size--; + + dberr_t err; + undo->last_page_no= trx_undo_free_page(undo->rseg, false, undo->hdr_page_no, + undo->last_page_no, mtr, &err); + return err; +} + +/** Truncate the tail of an undo log during rollback. +@param[in,out] undo undo log +@param[in] limit all undo logs after this limit will be discarded +@param[in] is_temp whether this is temporary undo log +@return error code */ +static dberr_t trx_undo_truncate_end(trx_undo_t &undo, undo_no_t limit, + bool is_temp) +{ + ut_ad(is_temp == !undo.rseg->is_persistent()); + + for (mtr_t mtr;;) + { + mtr.start(); + if (is_temp) + mtr.set_log_mode(MTR_LOG_NO_REDO); + + trx_undo_rec_t *trunc_here= nullptr; + undo.rseg->latch.wr_lock(SRW_LOCK_CALL); + dberr_t err; + buf_block_t *undo_block= + buf_page_get_gen(page_id_t{undo.rseg->space->id, undo.last_page_no}, + 0, RW_X_LATCH, nullptr, BUF_GET, &mtr, &err); + if (UNIV_UNLIKELY(!undo_block)) + goto func_exit; + + for (trx_undo_rec_t *rec= + trx_undo_page_get_last_rec(undo_block, + undo.hdr_page_no, undo.hdr_offset); + rec; ) + { + if (trx_undo_rec_get_undo_no(rec) < limit) + goto func_exit; + /* Truncate at least this record off, maybe more */ + trunc_here= rec; + rec= trx_undo_page_get_prev_rec(undo_block, rec, + undo.hdr_page_no, undo.hdr_offset); + } + + if (undo.last_page_no != undo.hdr_page_no) + { + err= trx_undo_free_last_page(&undo, &mtr); + if (UNIV_UNLIKELY(err != DB_SUCCESS)) + goto func_exit; + undo.rseg->latch.wr_unlock(); + mtr.commit(); + continue; + } + +func_exit: + undo.rseg->latch.wr_unlock(); + + if (trunc_here && err == DB_SUCCESS) + mtr.write<2>(*undo_block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_FREE + + undo_block->page.frame, + ulint(trunc_here - undo_block->page.frame)); + + mtr.commit(); + return err; + } +} + +/** Try to truncate the undo logs. +@param trx transaction +@return error code */ +dberr_t trx_undo_try_truncate(const trx_t &trx) +{ + if (trx_undo_t *undo= trx.rsegs.m_redo.undo) + { + ut_ad(undo->rseg == trx.rsegs.m_redo.rseg); + if (dberr_t err= trx_undo_truncate_end(*undo, trx.undo_no, false)) + return err; + } + + if (trx_undo_t *undo = trx.rsegs.m_noredo.undo) + { + ut_ad(undo->rseg == trx.rsegs.m_noredo.rseg); + if (dberr_t err= trx_undo_truncate_end(*undo, trx.undo_no, true)) + return err; + } + + return DB_SUCCESS; +} + +/** Truncate the head of an undo log. +NOTE that only whole pages are freed; the header page is not +freed, but emptied, if all the records there are below the limit. +@param[in,out] rseg rollback segment +@param[in] hdr_page_no header page number +@param[in] hdr_offset header offset on the page +@param[in] limit first undo number to preserve +(everything below the limit will be truncated) +@return error code */ +dberr_t +trx_undo_truncate_start( + trx_rseg_t* rseg, + uint32_t hdr_page_no, + uint16_t hdr_offset, + undo_no_t limit) +{ + trx_undo_rec_t* rec; + trx_undo_rec_t* last_rec; + mtr_t mtr; + + if (!limit) { + return DB_SUCCESS; + } +loop: + mtr_start(&mtr); + + if (!rseg->is_persistent()) { + mtr.set_log_mode(MTR_LOG_NO_REDO); + } + + dberr_t err; + const buf_block_t* undo_page; + rec = trx_undo_get_first_rec(*rseg->space, hdr_page_no, hdr_offset, + RW_X_LATCH, undo_page, &mtr, &err); + if (rec == NULL) { + /* Already empty */ +done: + mtr.commit(); + return err; + } + + last_rec = trx_undo_page_get_last_rec(undo_page, hdr_page_no, + hdr_offset); + if (trx_undo_rec_get_undo_no(last_rec) >= limit) { + goto done; + } + + if (undo_page->page.id().page_no() == hdr_page_no) { + uint16_t end = mach_read_from_2(hdr_offset + TRX_UNDO_NEXT_LOG + + undo_page->page.frame); + if (end == 0) { + end = mach_read_from_2(TRX_UNDO_PAGE_HDR + + TRX_UNDO_PAGE_FREE + + undo_page->page.frame); + } + + mtr.write<2>(*undo_page, undo_page->page.frame + hdr_offset + + TRX_UNDO_LOG_START, end); + } else { + trx_undo_free_page(rseg, true, hdr_page_no, + undo_page->page.id().page_no(), &mtr, &err); + if (err != DB_SUCCESS) { + goto done; + } + } + + mtr.commit(); + goto loop; +} + +/** Frees an undo log segment which is not in the history list. +@param undo temporary undo log */ +static void trx_undo_seg_free(const trx_undo_t *undo) +{ + ut_ad(undo->id < TRX_RSEG_N_SLOTS); + + trx_rseg_t *const rseg= undo->rseg; + bool finished; + mtr_t mtr; + ut_ad(rseg->space == fil_system.temp_space); + + do + { + mtr.start(); + mtr.set_log_mode(MTR_LOG_NO_REDO); + + finished= true; + + if (buf_block_t *block= + buf_page_get(page_id_t(SRV_TMP_SPACE_ID, undo->hdr_page_no), 0, + RW_X_LATCH, &mtr)) + { + fseg_header_t *file_seg= TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER + + block->page.frame; + + finished= fseg_free_step(file_seg, &mtr); + + if (!finished); + else if (buf_block_t* rseg_header = rseg->get(&mtr, nullptr)) + { + static_assert(FIL_NULL == 0xffffffff, "compatibility"); + mtr.memset(rseg_header, TRX_RSEG + TRX_RSEG_UNDO_SLOTS + + undo->id * TRX_RSEG_SLOT_SIZE, 4, 0xff); + MONITOR_DEC(MONITOR_NUM_UNDO_SLOT_USED); + } + } + + mtr.commit(); + } + while (!finished); +} + +/*========== UNDO LOG MEMORY COPY INITIALIZATION =====================*/ + +/** Read an undo log when starting up the database. +@param[in,out] rseg rollback segment +@param[in] id rollback segment slot +@param[in] page_no undo log segment page number +@param[in,out] max_trx_id the largest observed transaction ID +@return the undo log +@retval nullptr on error */ +trx_undo_t * +trx_undo_mem_create_at_db_start(trx_rseg_t *rseg, ulint id, uint32_t page_no, + trx_id_t &max_trx_id) +{ + mtr_t mtr; + XID xid; + + ut_ad(id < TRX_RSEG_N_SLOTS); + + mtr.start(); + const buf_block_t* block = buf_page_get( + page_id_t(rseg->space->id, page_no), 0, RW_X_LATCH, &mtr); + if (UNIV_UNLIKELY(!block)) { +corrupted: + mtr.commit(); + return nullptr; + } + + const uint16_t type = mach_read_from_2(TRX_UNDO_PAGE_HDR + + TRX_UNDO_PAGE_TYPE + + block->page.frame); + if (UNIV_UNLIKELY(type > 2)) { +corrupted_type: + sql_print_error("InnoDB: unsupported undo header type %u", + type); + goto corrupted; + } + + uint16_t offset = mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG + + block->page.frame); + if (offset < TRX_UNDO_SEG_HDR + TRX_UNDO_SEG_HDR_SIZE || + offset >= srv_page_size - TRX_UNDO_LOG_OLD_HDR_SIZE) { + sql_print_error("InnoDB: invalid undo header offset %u", + offset); + goto corrupted; + } + + const trx_ulogf_t* const undo_header = block->page.frame + offset; + uint16_t state = mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_STATE + + block->page.frame); + switch (state) { + case TRX_UNDO_ACTIVE: + case TRX_UNDO_PREPARED: + if (UNIV_LIKELY(type != 1)) { + break; + } + sql_print_error("InnoDB: upgrade from older version than" + " MariaDB 10.3 requires clean shutdown"); + goto corrupted; + default: + sql_print_error("InnoDB: unsupported undo header state %u", + state); + goto corrupted; + case TRX_UNDO_CACHED: + if (UNIV_UNLIKELY(type != 0)) { + /* This undo page was not updated by MariaDB + 10.3 or later. The TRX_UNDO_TRX_NO field may + contain garbage. */ + break; + } + goto read_trx_no; + case TRX_UNDO_TO_PURGE: + if (UNIV_UNLIKELY(type == 1)) { + goto corrupted_type; + } + read_trx_no: + trx_id_t id = mach_read_from_8(TRX_UNDO_TRX_NO + undo_header); + if (id >> 48) { + sql_print_error("InnoDB: corrupted TRX_NO %llx", id); + goto corrupted; + } + if (id > max_trx_id) { + max_trx_id = id; + } + } + + /* Read X/Open XA transaction identification if it exists, or + set it to NULL. */ + + if (undo_header[TRX_UNDO_XID_EXISTS]) { + trx_undo_read_xid(undo_header, &xid); + } else { + xid.null(); + } + + trx_id_t trx_id = mach_read_from_8(undo_header + TRX_UNDO_TRX_ID); + if (trx_id >> 48) { + sql_print_error("InnoDB: corrupted TRX_ID %llx", trx_id); + goto corrupted; + } + if (trx_id > max_trx_id) { + max_trx_id = trx_id; + } + + trx_undo_t* undo = trx_undo_mem_create( + rseg, id, trx_id, &xid, page_no, offset); + if (!undo) { + return undo; + } + + undo->dict_operation = undo_header[TRX_UNDO_DICT_TRANS]; + undo->size = flst_get_len(TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST + + block->page.frame); + + fil_addr_t last_addr = flst_get_last( + TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST + block->page.frame); + + undo->last_page_no = last_addr.page; + undo->top_page_no = last_addr.page; + + const buf_block_t* last = buf_page_get( + page_id_t(rseg->space->id, undo->last_page_no), 0, + RW_X_LATCH, &mtr); + + if (UNIV_UNLIKELY(!last)) { + ut_free(undo); + goto corrupted; + } + + if (const trx_undo_rec_t* rec = trx_undo_page_get_last_rec( + last, page_no, offset)) { + undo->top_offset = static_cast<uint16_t>( + rec - last->page.frame); + undo->top_undo_no = trx_undo_rec_get_undo_no(rec); + ut_ad(!undo->empty()); + } else { + undo->top_undo_no = IB_ID_MAX; + ut_ad(undo->empty()); + } + + undo->state = state; + + if (state != TRX_UNDO_CACHED) { + UT_LIST_ADD_LAST(rseg->undo_list, undo); + } else { + UT_LIST_ADD_LAST(rseg->undo_cached, undo); + MONITOR_INC(MONITOR_NUM_UNDO_SLOT_CACHED); + } + + mtr.commit(); + return undo; +} + +/********************************************************************//** +Creates and initializes an undo log memory object. +@return own: the undo log memory object */ +static +trx_undo_t* +trx_undo_mem_create( +/*================*/ + trx_rseg_t* rseg, /*!< in: rollback segment memory object */ + ulint id, /*!< in: slot index within rseg */ + trx_id_t trx_id, /*!< in: id of the trx for which the undo log + is created */ + const XID* xid, /*!< in: X/Open transaction identification */ + uint32_t page_no,/*!< in: undo log header page number */ + uint16_t offset) /*!< in: undo log header byte offset on page */ +{ + trx_undo_t* undo; + + ut_a(id < TRX_RSEG_N_SLOTS); + + undo = static_cast<trx_undo_t*>(ut_malloc_nokey(sizeof(*undo))); + + if (undo == NULL) { + + return(NULL); + } + + undo->id = id; + undo->state = TRX_UNDO_ACTIVE; + undo->trx_id = trx_id; + undo->xid = *xid; + + undo->dict_operation = FALSE; + + undo->rseg = rseg; + + undo->hdr_page_no = page_no; + undo->hdr_offset = offset; + undo->last_page_no = page_no; + undo->size = 1; + + undo->top_undo_no = IB_ID_MAX; + undo->top_page_no = page_no; + undo->guess_block = NULL; + ut_ad(undo->empty()); + + return(undo); +} + +/********************************************************************//** +Initializes a cached undo log object for new use. */ +static +void +trx_undo_mem_init_for_reuse( +/*========================*/ + trx_undo_t* undo, /*!< in: undo log to init */ + trx_id_t trx_id, /*!< in: id of the trx for which the undo log + is created */ + const XID* xid, /*!< in: X/Open XA transaction identification*/ + uint16_t offset) /*!< in: undo log header byte offset on page */ +{ + ut_a(undo->id < TRX_RSEG_N_SLOTS); + + undo->state = TRX_UNDO_ACTIVE; + undo->trx_id = trx_id; + undo->xid = *xid; + + undo->dict_operation = FALSE; + + undo->hdr_offset = offset; + undo->top_undo_no = IB_ID_MAX; + ut_ad(undo->empty()); +} + +/** Create an undo log. +@param[in,out] trx transaction +@param[in,out] rseg rollback segment +@param[out] undo undo log object +@param[out] err error code +@param[in,out] mtr mini-transaction +@return undo log block +@retval NULL on failure */ +static MY_ATTRIBUTE((nonnull, warn_unused_result)) +buf_block_t* +trx_undo_create(trx_t* trx, trx_rseg_t* rseg, trx_undo_t** undo, + dberr_t* err, mtr_t* mtr) +{ + ulint id; + buf_block_t* block = rseg->get(mtr, err); + + if (block) { + block = trx_undo_seg_create(rseg->space, block, &id, err, mtr); + } + + if (!block) { + return NULL; + } + + rseg->curr_size++; + + uint16_t offset = trx_undo_header_create(block, trx->id, mtr); + + *undo = trx_undo_mem_create(rseg, id, trx->id, &trx->xid, + block->page.id().page_no(), offset); + if (*undo == NULL) { + *err = DB_OUT_OF_MEMORY; + /* FIXME: this will not free the undo block to the file */ + return NULL; + } else if (rseg != trx->rsegs.m_redo.rseg) { + return block; + } + + if (trx->dict_operation) { + (*undo)->dict_operation = true; + mtr->write<1,mtr_t::MAYBE_NOP>(*block, + block->page.frame + offset + + TRX_UNDO_DICT_TRANS, 1U); + mtr->write<8,mtr_t::MAYBE_NOP>(*block, + block->page.frame + offset + + TRX_UNDO_TABLE_ID, 0U); + } + + *err = DB_SUCCESS; + return block; +} + +/*================ UNDO LOG ASSIGNMENT AND CLEANUP =====================*/ + +/** Reuse a cached undo log block. +@param[in,out] trx transaction +@param[in,out] rseg rollback segment +@param[out] pundo the undo log memory object +@param[in,out] mtr mini-transaction +@return the undo log block +@retval NULL if none cached */ +static +buf_block_t* +trx_undo_reuse_cached(trx_t* trx, trx_rseg_t* rseg, trx_undo_t** pundo, + mtr_t* mtr) +{ + trx_undo_t* undo = UT_LIST_GET_FIRST(rseg->undo_cached); + if (!undo) { + return NULL; + } + + ut_ad(undo->size == 1); + ut_ad(undo->id < TRX_RSEG_N_SLOTS); + + buf_block_t* block = buf_page_get(page_id_t(undo->rseg->space->id, + undo->hdr_page_no), + 0, RW_X_LATCH, mtr); + if (!block) { + return NULL; + } + + UT_LIST_REMOVE(rseg->undo_cached, undo); + MONITOR_DEC(MONITOR_NUM_UNDO_SLOT_CACHED); + + *pundo = undo; + + uint16_t offset = trx_undo_header_create(block, trx->id, mtr); + + trx_undo_mem_init_for_reuse(undo, trx->id, &trx->xid, offset); + + if (rseg != trx->rsegs.m_redo.rseg) { + return block; + } + + if (trx->dict_operation) { + undo->dict_operation = TRUE; + mtr->write<1,mtr_t::MAYBE_NOP>(*block, + block->page.frame + offset + + TRX_UNDO_DICT_TRANS, 1U); + mtr->write<8,mtr_t::MAYBE_NOP>(*block, + block->page.frame + offset + + TRX_UNDO_TABLE_ID, 0U); + } + + return block; +} + +/** Assign an undo log for a persistent transaction. +A new undo log is created or a cached undo log reused. +@param[in,out] trx transaction +@param[out] err error code +@param[in,out] mtr mini-transaction +@return the undo log block +@retval NULL on error */ +buf_block_t* +trx_undo_assign(trx_t* trx, dberr_t* err, mtr_t* mtr) +{ + ut_ad(mtr->get_log_mode() == MTR_LOG_ALL); + + trx_undo_t* undo = trx->rsegs.m_redo.undo; + + if (undo) { + return buf_page_get_gen( + page_id_t(undo->rseg->space->id, undo->last_page_no), + 0, RW_X_LATCH, undo->guess_block, + BUF_GET, mtr, err); + } + + trx_rseg_t* rseg = trx->rsegs.m_redo.rseg; + + rseg->latch.wr_lock(SRW_LOCK_CALL); + buf_block_t* block = trx_undo_reuse_cached( + trx, rseg, &trx->rsegs.m_redo.undo, mtr); + + if (!block) { + block = trx_undo_create(trx, rseg, &trx->rsegs.m_redo.undo, + err, mtr); + ut_ad(!block == (*err != DB_SUCCESS)); + if (!block) { + goto func_exit; + } + } else { + *err = DB_SUCCESS; + } + + UT_LIST_ADD_FIRST(rseg->undo_list, trx->rsegs.m_redo.undo); + +func_exit: + rseg->latch.wr_unlock(); + return block; +} + +/** Assign an undo log for a transaction. +A new undo log is created or a cached undo log reused. +@param[in,out] trx transaction +@param[in] rseg rollback segment +@param[out] undo the undo log +@param[out] err error code +@param[in,out] mtr mini-transaction +@return the undo log block +@retval NULL on error */ +buf_block_t* +trx_undo_assign_low(trx_t* trx, trx_rseg_t* rseg, trx_undo_t** undo, + dberr_t* err, mtr_t* mtr) +{ + ut_d(const bool is_temp = rseg == trx->rsegs.m_noredo.rseg); + ut_ad(rseg == trx->rsegs.m_redo.rseg + || rseg == trx->rsegs.m_noredo.rseg); + ut_ad(undo == (is_temp + ? &trx->rsegs.m_noredo.undo + : &trx->rsegs.m_redo.undo)); + ut_ad(mtr->get_log_mode() + == (is_temp ? MTR_LOG_NO_REDO : MTR_LOG_ALL)); + + if (*undo) { + return buf_page_get_gen( + page_id_t(rseg->space->id, (*undo)->last_page_no), + 0, RW_X_LATCH, (*undo)->guess_block, + BUF_GET, mtr, err); + } + + DBUG_EXECUTE_IF( + "ib_create_table_fail_too_many_trx", + *err = DB_TOO_MANY_CONCURRENT_TRXS; return NULL; + ); + + rseg->latch.wr_lock(SRW_LOCK_CALL); + + buf_block_t* block = trx_undo_reuse_cached(trx, rseg, undo, mtr); + + if (!block) { + block = trx_undo_create(trx, rseg, undo, err, mtr); + ut_ad(!block == (*err != DB_SUCCESS)); + if (!block) { + goto func_exit; + } + } else { + *err = DB_SUCCESS; + } + + UT_LIST_ADD_FIRST(rseg->undo_list, *undo); + +func_exit: + rseg->latch.wr_unlock(); + return block; +} + +/******************************************************************//** +Sets the state of the undo log segment at a transaction finish. +@return undo log segment header page, x-latched */ +buf_block_t* +trx_undo_set_state_at_finish( +/*=========================*/ + trx_undo_t* undo, /*!< in: undo log memory copy */ + mtr_t* mtr) /*!< in: mtr */ +{ + ut_ad(undo->id < TRX_RSEG_N_SLOTS); + + buf_block_t *block= + buf_page_get(page_id_t(undo->rseg->space->id, undo->hdr_page_no), 0, + RW_X_LATCH, mtr); + /* This function is invoked during transaction commit, which is not + allowed to fail. If we get a corrupted undo header, we will crash here. */ + ut_a(block); + const uint16_t state = undo->size == 1 && + TRX_UNDO_PAGE_REUSE_LIMIT > + mach_read_from_2(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_FREE + + block->page.frame) + ? TRX_UNDO_CACHED + : TRX_UNDO_TO_PURGE; + + undo->state= state; + mtr->write<2>(*block, TRX_UNDO_SEG_HDR + TRX_UNDO_STATE + block->page.frame, + state); + return block; +} + +/** Set the state of the undo log segment at a XA PREPARE or XA ROLLBACK. +@param[in,out] trx transaction +@param[in,out] undo undo log +@param[in] rollback false=XA PREPARE, true=XA ROLLBACK +@param[in,out] mtr mini-transaction +@return undo log segment header page, x-latched */ +void trx_undo_set_state_at_prepare(trx_t *trx, trx_undo_t *undo, bool rollback, + mtr_t *mtr) +{ + ut_a(undo->id < TRX_RSEG_N_SLOTS); + + buf_block_t* block = buf_page_get( + page_id_t(undo->rseg->space->id, undo->hdr_page_no), 0, + RW_X_LATCH, mtr); + if (UNIV_UNLIKELY(!block)) { + /* In case of !rollback the undo header page + corruption would leave the transaction object in an + unexpected (active) state. */ + ut_a(rollback); + return; + } + + if (rollback) { + ut_ad(undo->state == TRX_UNDO_PREPARED); + mtr->write<2>(*block, TRX_UNDO_SEG_HDR + TRX_UNDO_STATE + + block->page.frame, TRX_UNDO_ACTIVE); + return; + } + + /*------------------------------*/ + ut_ad(undo->state == TRX_UNDO_ACTIVE); + undo->state = TRX_UNDO_PREPARED; + undo->xid = trx->xid; + /*------------------------------*/ + + mtr->write<2>(*block, TRX_UNDO_SEG_HDR + TRX_UNDO_STATE + + block->page.frame, undo->state); + uint16_t offset = mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG + + block->page.frame); + mtr->write<1>(*block, block->page.frame + offset + TRX_UNDO_XID_EXISTS, + 1U); + + trx_undo_write_xid(block, offset, undo->xid, mtr); +} + +/** Free temporary undo log after commit or rollback. +The information is not needed after a commit or rollback, therefore +the data can be discarded. +@param undo temporary undo log */ +void trx_undo_commit_cleanup(trx_undo_t *undo) +{ + trx_rseg_t* rseg = undo->rseg; + ut_ad(rseg->space == fil_system.temp_space); + + rseg->latch.wr_lock(SRW_LOCK_CALL); + + UT_LIST_REMOVE(rseg->undo_list, undo); + + if (undo->state == TRX_UNDO_CACHED) { + UT_LIST_ADD_FIRST(rseg->undo_cached, undo); + MONITOR_INC(MONITOR_NUM_UNDO_SLOT_CACHED); + undo = nullptr; + } else { + ut_ad(undo->state == TRX_UNDO_TO_PURGE); + + /* Delete first the undo log segment in the file */ + trx_undo_seg_free(undo); + + ut_ad(rseg->curr_size > undo->size); + rseg->curr_size -= undo->size; + } + + rseg->latch.wr_unlock(); + ut_free(undo); +} + +/** At shutdown, frees the undo logs of a transaction. */ +void trx_undo_free_at_shutdown(trx_t *trx) +{ + if (trx_undo_t*& undo = trx->rsegs.m_redo.undo) { + switch (undo->state) { + case TRX_UNDO_PREPARED: + break; + case TRX_UNDO_CACHED: + case TRX_UNDO_TO_PURGE: + ut_ad(trx_state_eq(trx, + TRX_STATE_COMMITTED_IN_MEMORY)); + /* fall through */ + case TRX_UNDO_ACTIVE: + /* trx_t::commit_state() assigns + trx->state = TRX_STATE_COMMITTED_IN_MEMORY. */ + ut_a(!srv_was_started + || srv_read_only_mode + || srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO + || srv_fast_shutdown); + break; + default: + ut_error; + } + + UT_LIST_REMOVE(trx->rsegs.m_redo.rseg->undo_list, undo); + ut_free(undo); + undo = NULL; + } + if (trx_undo_t*& undo = trx->rsegs.m_noredo.undo) { + ut_a(undo->state == TRX_UNDO_PREPARED); + + UT_LIST_REMOVE(trx->rsegs.m_noredo.rseg->undo_list, undo); + ut_free(undo); + undo = NULL; + } +} |