Adding upstream version 1:10.5.12.upstream/1%10.5.12upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 268 insertions, 0 deletions

diff --git a/storage/innobase/include/trx0purge.h b/storage/innobase/include/trx0purge.h
new file mode 100644
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+++ b/storage/innobase/include/trx0purge.h
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+/*****************************************************************************
+
+Copyright (c) 1996, 2016, 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 include/trx0purge.h
+Purge old versions
+
+Created 3/26/1996 Heikki Tuuri
+*******************************************************/
+
+#ifndef trx0purge_h
+#define trx0purge_h
+
+#include "trx0rseg.h"
+#include "que0types.h"
+
+#include <queue>
+
+/** A dummy undo record used as a return value when we have a whole undo log
+which needs no purge */
+extern trx_undo_rec_t	trx_purge_dummy_rec;
+
+/** Prepend the history list with an undo log.
+Remove the undo log segment from the rseg slot if it is too big for reuse.
+@param[in]	trx		transaction
+@param[in,out]	undo		undo log
+@param[in,out]	mtr		mini-transaction */
+void
+trx_purge_add_undo_to_history(const trx_t* trx, trx_undo_t*& undo, mtr_t* mtr);
+/**
+Run a purge batch.
+@param n_tasks   number of purge tasks to submit to the queue
+@param truncate  whether to truncate the history at the end of the batch
+@return number of undo log pages handled in the batch */
+ulint trx_purge(ulint n_tasks, bool truncate);
+
+/** Rollback segements from a given transaction with trx-no
+scheduled for purge. */
+class TrxUndoRsegs {
+private:
+	typedef std::vector<trx_rseg_t*, ut_allocator<trx_rseg_t*> >
+		trx_rsegs_t;
+public:
+	typedef trx_rsegs_t::iterator iterator;
+	typedef trx_rsegs_t::const_iterator const_iterator;
+
+	TrxUndoRsegs() {}
+
+	/** Constructor */
+	TrxUndoRsegs(trx_rseg_t& rseg)
+		: trx_no(rseg.last_trx_no()), m_rsegs(1, &rseg) {}
+	/** Constructor */
+	TrxUndoRsegs(trx_id_t trx_no, trx_rseg_t& rseg)
+		: trx_no(trx_no), m_rsegs(1, &rseg) {}
+
+	bool operator!=(const TrxUndoRsegs& other) const
+	{ return trx_no != other.trx_no; }
+	bool empty() const { return m_rsegs.empty(); }
+	void erase(iterator& it) { m_rsegs.erase(it); }
+	iterator begin() { return(m_rsegs.begin()); }
+	iterator end() { return(m_rsegs.end()); }
+	const_iterator begin() const { return m_rsegs.begin(); }
+	const_iterator end() const { return m_rsegs.end(); }
+
+	/** Compare two TrxUndoRsegs based on trx_no.
+	@param elem1 first element to compare
+	@param elem2 second element to compare
+	@return true if elem1 > elem2 else false.*/
+	bool operator()(const TrxUndoRsegs& lhs, const TrxUndoRsegs& rhs)
+	{
+		return(lhs.trx_no > rhs.trx_no);
+	}
+
+	/** Copy of trx_rseg_t::last_trx_no() */
+	trx_id_t trx_no= 0;
+private:
+	/** Rollback segments of a transaction, scheduled for purge. */
+	trx_rsegs_t m_rsegs{};
+};
+
+typedef std::priority_queue<
+	TrxUndoRsegs,
+	std::vector<TrxUndoRsegs, ut_allocator<TrxUndoRsegs> >,
+	TrxUndoRsegs>	purge_pq_t;
+
+/** Chooses the rollback segment with the oldest committed transaction */
+struct TrxUndoRsegsIterator {
+	/** Constructor */
+	TrxUndoRsegsIterator();
+	/** Sets the next rseg to purge in purge_sys.
+	Executed in the purge coordinator thread.
+	@return whether anything is to be purged */
+	inline bool set_next();
+
+private:
+	// Disable copying
+	TrxUndoRsegsIterator(const TrxUndoRsegsIterator&);
+	TrxUndoRsegsIterator& operator=(const TrxUndoRsegsIterator&);
+
+	/** The current element to process */
+	TrxUndoRsegs			m_rsegs;
+	/** Track the current element in m_rsegs */
+	TrxUndoRsegs::const_iterator	m_iter;
+};
+
+/** The control structure used in the purge operation */
+class purge_sys_t
+{
+public:
+	/** latch protecting view, m_enabled */
+	MY_ALIGNED(CACHE_LINE_SIZE)
+	mutable rw_lock_t		latch;
+private:
+	/** The purge will not remove undo logs which are >= this view */
+	MY_ALIGNED(CACHE_LINE_SIZE)
+	ReadViewBase	view;
+	/** whether purge is enabled; protected by latch and std::atomic */
+	std::atomic<bool>		m_enabled;
+	/** number of pending stop() calls without resume() */
+	Atomic_counter<int32_t>		m_paused;
+public:
+	que_t*		query;		/*!< The query graph which will do the
+					parallelized purge operation */
+
+	/** Iterator to the undo log records of committed transactions */
+	struct iterator
+	{
+		bool operator<=(const iterator& other) const
+		{
+			if (trx_no < other.trx_no) return true;
+			if (trx_no > other.trx_no) return false;
+			return undo_no <= other.undo_no;
+		}
+
+		/** trx_t::no of the committed transaction */
+		trx_id_t	trx_no;
+		/** The record number within the committed transaction's undo
+		log, increasing, purged from from 0 onwards */
+		undo_no_t	undo_no;
+	};
+
+	/** The tail of the purge queue; the last parsed undo log of a
+	committed transaction. */
+	iterator	tail;
+	/** The head of the purge queue; any older undo logs of committed
+	transactions may be discarded (history list truncation). */
+	iterator	head;
+	/*-----------------------------*/
+	bool		next_stored;	/*!< whether rseg holds the next record
+					to purge */
+	trx_rseg_t*	rseg;		/*!< Rollback segment for the next undo
+					record to purge */
+	uint32_t	page_no;	/*!< Page number for the next undo
+					record to purge, page number of the
+					log header, if dummy record */
+	uint32_t	hdr_page_no;	/*!< Header page of the undo log where
+					the next record to purge belongs */
+	uint16_t	offset;		/*!< Page offset for the next undo
+					record to purge, 0 if the dummy
+					record */
+	uint16_t	hdr_offset;	/*!< Header byte offset on the page */
+
+
+	TrxUndoRsegsIterator
+			rseg_iter;	/*!< Iterator to get the next rseg
+					to process */
+
+	purge_pq_t	purge_queue;	/*!< Binary min-heap, ordered on
+					TrxUndoRsegs::trx_no. It is protected
+					by the pq_mutex */
+	PQMutex		pq_mutex;	/*!< Mutex protecting purge_queue */
+
+	/** Undo tablespace file truncation (only accessed by the
+	srv_purge_coordinator_thread) */
+	struct {
+		/** The undo tablespace that is currently being truncated */
+		fil_space_t*	current;
+		/** The undo tablespace that was last truncated */
+		fil_space_t*	last;
+	} truncate;
+
+	/** Heap for reading the undo log records */
+	mem_heap_t*	heap;
+  /**
+    Constructor.
+
+    Some members may require late initialisation, thus we just mark object as
+    uninitialised. Real initialisation happens in create().
+  */
+
+  purge_sys_t(): m_enabled(false), heap(nullptr) {}
+
+  /** Create the instance */
+  void create();
+
+  /** Close the purge system on shutdown */
+  void close();
+
+  /** @return whether purge is enabled */
+  bool enabled() { return m_enabled.load(std::memory_order_relaxed); }
+  /** @return whether the purge coordinator is paused */
+  bool paused()
+  { return m_paused != 0; }
+
+  /** Enable purge at startup. Not protected by latch; the main thread
+  will wait for purge_sys.enabled() in srv_start() */
+  void coordinator_startup()
+  {
+    ut_ad(!enabled());
+    m_enabled.store(true, std::memory_order_relaxed);
+  }
+
+  /** Disable purge at shutdown */
+  void coordinator_shutdown()
+  {
+    ut_ad(enabled());
+    m_enabled.store(false, std::memory_order_relaxed);
+  }
+
+  /** @return whether the purge tasks are active */
+  bool running() const;
+  /** Stop purge during FLUSH TABLES FOR EXPORT */
+  void stop();
+  /** Resume purge at UNLOCK TABLES after FLUSH TABLES FOR EXPORT */
+  void resume();
+  /** A wrapper around ReadView::changes_visible(). */
+  bool changes_visible(trx_id_t id, const table_name_t &name) const
+  {
+    ut_ad(rw_lock_own(&latch, RW_LOCK_S));
+    return view.changes_visible(id, name);
+  }
+  /** A wrapper around ReadView::low_limit_no(). */
+  trx_id_t low_limit_no() const
+  {
+#if 0 /* Unfortunately we don't hold this assertion, see MDEV-22718. */
+    ut_ad(rw_lock_own(&latch, RW_LOCK_S));
+#endif
+    return view.low_limit_no();
+  }
+  /** A wrapper around trx_sys_t::clone_oldest_view(). */
+  void clone_oldest_view()
+  {
+    rw_lock_x_lock(&latch);
+    trx_sys.clone_oldest_view(&view);
+    rw_lock_x_unlock(&latch);
+  }
+};
+
+/** The global data structure coordinating a purge */
+extern purge_sys_t	purge_sys;
+
+#endif /* trx0purge_h */