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+/* Copyright (C) 2007 Google Inc.
+ Copyright (c) 2008 MySQL AB, 2009 Sun Microsystems, Inc.
+ Use is subject to license terms.
+
+ 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 St, Fifth Floor, Boston, MA 02110-1335 USA */
+
+
+#ifndef SEMISYNC_MASTER_H
+#define SEMISYNC_MASTER_H
+
+#include "semisync.h"
+#include "semisync_master_ack_receiver.h"
+
+#ifdef HAVE_PSI_INTERFACE
+extern PSI_mutex_key key_LOCK_rpl_semi_sync_master_enabled;
+extern PSI_mutex_key key_LOCK_binlog;
+extern PSI_cond_key key_COND_binlog_send;
+#endif
+
+struct Tranx_node {
+ char log_name[FN_REFLEN];
+ my_off_t log_pos;
+ struct Tranx_node *next; /* the next node in the sorted list */
+ struct Tranx_node *hash_next; /* the next node during hash collision */
+};
+
+/**
+ @class Tranx_node_allocator
+
+ This class provides memory allocating and freeing methods for
+ Tranx_node. The main target is performance.
+
+ @section ALLOCATE How to allocate a node
+ The pointer of the first node after 'last_node' in current_block is
+ returned. current_block will move to the next free Block when all nodes of
+ it are in use. A new Block is allocated and is put into the rear of the
+ Block link table if no Block is free.
+
+ The list starts up empty (ie, there is no allocated Block).
+
+ After some nodes are freed, there probably are some free nodes before
+ the sequence of the allocated nodes, but we do not reuse it. It is better
+ to keep the allocated nodes are in the sequence, for it is more efficient
+ for allocating and freeing Tranx_node.
+
+ @section FREENODE How to free nodes
+ There are two methods for freeing nodes. They are free_all_nodes and
+ free_nodes_before.
+
+ 'A Block is free' means all of its nodes are free.
+ @subsection free_nodes_before
+ As all allocated nodes are in the sequence, 'Before one node' means all
+ nodes before given node in the same Block and all Blocks before the Block
+ which containing the given node. As such, all Blocks before the given one
+ ('node') are free Block and moved into the rear of the Block link table.
+ The Block containing the given 'node', however, is not. For at least the
+ given 'node' is still in use. This will waste at most one Block, but it is
+ more efficient.
+ */
+#define BLOCK_TRANX_NODES 16
+class Tranx_node_allocator
+{
+public:
+ /**
+ @param reserved_nodes
+ The number of reserved Tranx_nodes. It is used to set 'reserved_blocks'
+ which can contain at least 'reserved_nodes' number of Tranx_nodes. When
+ freeing memory, we will reserve at least reserved_blocks of Blocks not
+ freed.
+ */
+ Tranx_node_allocator(uint reserved_nodes) :
+ reserved_blocks(reserved_nodes/BLOCK_TRANX_NODES +
+ (reserved_nodes%BLOCK_TRANX_NODES > 1 ? 2 : 1)),
+ first_block(NULL), last_block(NULL),
+ current_block(NULL), last_node(-1), block_num(0) {}
+
+ ~Tranx_node_allocator()
+ {
+ Block *block= first_block;
+ while (block != NULL)
+ {
+ Block *next= block->next;
+ free_block(block);
+ block= next;
+ }
+ }
+
+ /**
+ The pointer of the first node after 'last_node' in current_block is
+ returned. current_block will move to the next free Block when all nodes of
+ it are in use. A new Block is allocated and is put into the rear of the
+ Block link table if no Block is free.
+
+ @return Return a Tranx_node *, or NULL if an error occurred.
+ */
+ Tranx_node *allocate_node()
+ {
+ Tranx_node *trx_node;
+ Block *block= current_block;
+
+ if (last_node == BLOCK_TRANX_NODES-1)
+ {
+ current_block= current_block->next;
+ last_node= -1;
+ }
+
+ if (current_block == NULL && allocate_block())
+ {
+ current_block= block;
+ if (current_block)
+ last_node= BLOCK_TRANX_NODES-1;
+ return NULL;
+ }
+
+ trx_node= &(current_block->nodes[++last_node]);
+ trx_node->log_name[0] = '\0';
+ trx_node->log_pos= 0;
+ trx_node->next= 0;
+ trx_node->hash_next= 0;
+ return trx_node;
+ }
+
+ /**
+ All nodes are freed.
+
+ @return Return 0, or 1 if an error occurred.
+ */
+ int free_all_nodes()
+ {
+ current_block= first_block;
+ last_node= -1;
+ free_blocks();
+ return 0;
+ }
+
+ /**
+ All Blocks before the given 'node' are free Block and moved into the rear
+ of the Block link table.
+
+ @param node All nodes before 'node' will be freed
+
+ @return Return 0, or 1 if an error occurred.
+ */
+ int free_nodes_before(Tranx_node* node)
+ {
+ Block *block;
+ Block *prev_block= NULL;
+
+ block= first_block;
+ while (block != current_block->next)
+ {
+ /* Find the Block containing the given node */
+ if (&(block->nodes[0]) <= node && &(block->nodes[BLOCK_TRANX_NODES]) >= node)
+ {
+ /* All Blocks before the given node are put into the rear */
+ if (first_block != block)
+ {
+ last_block->next= first_block;
+ first_block= block;
+ last_block= prev_block;
+ last_block->next= NULL;
+ free_blocks();
+ }
+ return 0;
+ }
+ prev_block= block;
+ block= block->next;
+ }
+
+ /* Node does not find should never happen */
+ DBUG_ASSERT(0);
+ return 1;
+ }
+
+private:
+ uint reserved_blocks;
+
+ /**
+ A sequence memory which contains BLOCK_TRANX_NODES Tranx_nodes.
+
+ BLOCK_TRANX_NODES The number of Tranx_nodes which are in a Block.
+
+ next Every Block has a 'next' pointer which points to the next Block.
+ These linking Blocks constitute a Block link table.
+ */
+ struct Block {
+ Block *next;
+ Tranx_node nodes[BLOCK_TRANX_NODES];
+ };
+
+ /**
+ The 'first_block' is the head of the Block link table;
+ */
+ Block *first_block;
+ /**
+ The 'last_block' is the rear of the Block link table;
+ */
+ Block *last_block;
+
+ /**
+ current_block always points the Block in the Block link table in
+ which the last allocated node is. The Blocks before it are all in use
+ and the Blocks after it are all free.
+ */
+ Block *current_block;
+
+ /**
+ It always points to the last node which has been allocated in the
+ current_block.
+ */
+ int last_node;
+
+ /**
+ How many Blocks are in the Block link table.
+ */
+ uint block_num;
+
+ /**
+ Allocate a block and then assign it to current_block.
+ */
+ int allocate_block()
+ {
+ Block *block= (Block *)my_malloc(PSI_INSTRUMENT_ME, sizeof(Block), MYF(0));
+ if (block)
+ {
+ block->next= NULL;
+
+ if (first_block == NULL)
+ first_block= block;
+ else
+ last_block->next= block;
+
+ /* New Block is always put into the rear */
+ last_block= block;
+ /* New Block is always the current_block */
+ current_block= block;
+ ++block_num;
+ return 0;
+ }
+ return 1;
+ }
+
+ /**
+ Free a given Block.
+ @param block The Block will be freed.
+ */
+ void free_block(Block *block)
+ {
+ my_free(block);
+ --block_num;
+ }
+
+
+ /**
+ If there are some free Blocks and the total number of the Blocks in the
+ Block link table is larger than the 'reserved_blocks', Some free Blocks
+ will be freed until the total number of the Blocks is equal to the
+ 'reserved_blocks' or there is only one free Block behind the
+ 'current_block'.
+ */
+ void free_blocks()
+ {
+ if (current_block == NULL || current_block->next == NULL)
+ return;
+
+ /* One free Block is always kept behind the current block */
+ Block *block= current_block->next->next;
+ while (block_num > reserved_blocks && block != NULL)
+ {
+ Block *next= block->next;
+ free_block(block);
+ block= next;
+ }
+ current_block->next->next= block;
+ if (block == NULL)
+ last_block= current_block->next;
+ }
+};
+
+/**
+ This class manages memory for active transaction list.
+
+ We record each active transaction with a Tranx_node, each session
+ can have only one open transaction. Because of EVENT, the total
+ active transaction nodes can exceed the maximum allowed
+ connections.
+*/
+class Active_tranx
+ :public Trace {
+private:
+
+ Tranx_node_allocator m_allocator;
+ /* These two record the active transaction list in sort order. */
+ Tranx_node *m_trx_front, *m_trx_rear;
+
+ Tranx_node **m_trx_htb; /* A hash table on active transactions. */
+
+ int m_num_entries; /* maximum hash table entries */
+ mysql_mutex_t *m_lock; /* mutex lock */
+
+ inline void assert_lock_owner();
+
+ inline unsigned int calc_hash(const unsigned char *key, size_t length);
+ unsigned int get_hash_value(const char *log_file_name, my_off_t log_file_pos);
+
+ int compare(const char *log_file_name1, my_off_t log_file_pos1,
+ const Tranx_node *node2) {
+ return compare(log_file_name1, log_file_pos1,
+ node2->log_name, node2->log_pos);
+ }
+ int compare(const Tranx_node *node1,
+ const char *log_file_name2, my_off_t log_file_pos2) {
+ return compare(node1->log_name, node1->log_pos,
+ log_file_name2, log_file_pos2);
+ }
+ int compare(const Tranx_node *node1, const Tranx_node *node2) {
+ return compare(node1->log_name, node1->log_pos,
+ node2->log_name, node2->log_pos);
+ }
+
+public:
+ Active_tranx(mysql_mutex_t *lock, unsigned long trace_level);
+ ~Active_tranx();
+
+ /* Insert an active transaction node with the specified position.
+ *
+ * Return:
+ * 0: success; non-zero: error
+ */
+ int insert_tranx_node(const char *log_file_name, my_off_t log_file_pos);
+
+ /* Clear the active transaction nodes until(inclusive) the specified
+ * position.
+ * If log_file_name is NULL, everything will be cleared: the sorted
+ * list and the hash table will be reset to empty.
+ */
+ void clear_active_tranx_nodes(const char *log_file_name,
+ my_off_t log_file_pos);
+
+ /* Given a position, check to see whether the position is an active
+ * transaction's ending position by probing the hash table.
+ */
+ bool is_tranx_end_pos(const char *log_file_name, my_off_t log_file_pos);
+
+ /* Given two binlog positions, compare which one is bigger based on
+ * (file_name, file_position).
+ */
+ static int compare(const char *log_file_name1, my_off_t log_file_pos1,
+ const char *log_file_name2, my_off_t log_file_pos2);
+
+};
+
+/**
+ The extension class for the master of semi-synchronous replication
+*/
+class Repl_semi_sync_master
+ :public Repl_semi_sync_base {
+ Active_tranx *m_active_tranxs; /* active transaction list: the list will
+ be cleared when semi-sync switches off. */
+
+ /* True when init_object has been called */
+ bool m_init_done;
+
+ /* This cond variable is signaled when enough binlog has been sent to slave,
+ * so that a waiting trx can return the 'ok' to the client for a commit.
+ */
+ mysql_cond_t COND_binlog_send;
+
+ /* Mutex that protects the following state variables and the active
+ * transaction list.
+ * Under no cirumstances we can acquire mysql_bin_log.LOCK_log if we are
+ * already holding m_LOCK_binlog because it can cause deadlocks.
+ */
+ mysql_mutex_t LOCK_binlog;
+
+ /* This is set to true when m_reply_file_name contains meaningful data. */
+ bool m_reply_file_name_inited;
+
+ /* The binlog name up to which we have received replies from any slaves. */
+ char m_reply_file_name[FN_REFLEN];
+
+ /* The position in that file up to which we have the reply from any slaves. */
+ my_off_t m_reply_file_pos;
+
+ /* This is set to true when we know the 'smallest' wait position. */
+ bool m_wait_file_name_inited;
+
+ /* NULL, or the 'smallest' filename that a transaction is waiting for
+ * slave replies.
+ */
+ char m_wait_file_name[FN_REFLEN];
+
+ /* The smallest position in that file that a trx is waiting for: the trx
+ * can proceed and send an 'ok' to the client when the master has got the
+ * reply from the slave indicating that it already got the binlog events.
+ */
+ my_off_t m_wait_file_pos;
+
+ /* This is set to true when we know the 'largest' transaction commit
+ * position in the binlog file.
+ * We always maintain the position no matter whether semi-sync is switched
+ * on switched off. When a transaction wait timeout occurs, semi-sync will
+ * switch off. Binlog-dump thread can use the three fields to detect when
+ * slaves catch up on replication so that semi-sync can switch on again.
+ */
+ bool m_commit_file_name_inited;
+
+ /* The 'largest' binlog filename that a commit transaction is seeing. */
+ char m_commit_file_name[FN_REFLEN];
+
+ /* The 'largest' position in that file that a commit transaction is seeing. */
+ my_off_t m_commit_file_pos;
+
+ /* All global variables which can be set by parameters. */
+ volatile bool m_master_enabled; /* semi-sync is enabled on the master */
+ unsigned long m_wait_timeout; /* timeout period(ms) during tranx wait */
+
+ bool m_state; /* whether semi-sync is switched */
+
+ /*Waiting for ACK before/after innodb commit*/
+ ulong m_wait_point;
+
+ void lock();
+ void unlock();
+ void cond_broadcast();
+ int cond_timewait(struct timespec *wait_time);
+
+ /* Is semi-sync replication on? */
+ bool is_on() {
+ return (m_state);
+ }
+
+ void set_master_enabled(bool enabled) {
+ m_master_enabled = enabled;
+ }
+
+ /* Switch semi-sync off because of timeout in transaction waiting. */
+ void switch_off();
+
+ /* Switch semi-sync on when slaves catch up. */
+ int try_switch_on(int server_id,
+ const char *log_file_name, my_off_t log_file_pos);
+
+ public:
+ Repl_semi_sync_master();
+ ~Repl_semi_sync_master() {}
+
+ void cleanup();
+
+ bool get_master_enabled() {
+ return m_master_enabled;
+ }
+ void set_trace_level(unsigned long trace_level) {
+ m_trace_level = trace_level;
+ if (m_active_tranxs)
+ m_active_tranxs->m_trace_level = trace_level;
+ }
+
+ /* Set the transaction wait timeout period, in milliseconds. */
+ void set_wait_timeout(unsigned long wait_timeout) {
+ m_wait_timeout = wait_timeout;
+ }
+
+ /*set the ACK point, after binlog sync or after transaction commit*/
+ void set_wait_point(unsigned long ack_point)
+ {
+ m_wait_point = ack_point;
+ }
+
+ ulong wait_point() //no cover line
+ {
+ return m_wait_point; //no cover line
+ }
+
+ /* Initialize this class after MySQL parameters are initialized. this
+ * function should be called once at bootstrap time.
+ */
+ int init_object();
+
+ /* Enable the object to enable semi-sync replication inside the master. */
+ int enable_master();
+
+ /* Disable the object to disable semi-sync replication inside the master. */
+ void disable_master();
+
+ /* Add a semi-sync replication slave */
+ void add_slave();
+
+ /* Remove a semi-sync replication slave */
+ void remove_slave();
+
+ /* It parses a reply packet and call report_reply_binlog to handle it. */
+ int report_reply_packet(uint32 server_id, const uchar *packet,
+ ulong packet_len);
+
+ /* In semi-sync replication, reports up to which binlog position we have
+ * received replies from the slave indicating that it already get the events.
+ *
+ * Input:
+ * server_id - (IN) master server id number
+ * log_file_name - (IN) binlog file name
+ * end_offset - (IN) the offset in the binlog file up to which we have
+ * the replies from the slave
+ *
+ * Return:
+ * 0: success; non-zero: error
+ */
+ int report_reply_binlog(uint32 server_id,
+ const char* log_file_name,
+ my_off_t end_offset);
+
+ /* Commit a transaction in the final step. This function is called from
+ * InnoDB before returning from the low commit. If semi-sync is switch on,
+ * the function will wait to see whether binlog-dump thread get the reply for
+ * the events of the transaction. Remember that this is not a direct wait,
+ * instead, it waits to see whether the binlog-dump thread has reached the
+ * point. If the wait times out, semi-sync status will be switched off and
+ * all other transaction would not wait either.
+ *
+ * Input: (the transaction events' ending binlog position)
+ * trx_wait_binlog_name - (IN) ending position's file name
+ * trx_wait_binlog_pos - (IN) ending position's file offset
+ *
+ * Return:
+ * 0: success; non-zero: error
+ */
+ int commit_trx(const char* trx_wait_binlog_name,
+ my_off_t trx_wait_binlog_pos);
+
+ /*Wait for ACK after writing/sync binlog to file*/
+ int wait_after_sync(const char* log_file, my_off_t log_pos);
+
+ /*Wait for ACK after commting the transaction*/
+ int wait_after_commit(THD* thd, bool all);
+
+ /*Wait after the transaction is rollback*/
+ int wait_after_rollback(THD *thd, bool all);
+ /*Store the current binlog position in m_active_tranxs. This position should
+ * be acked by slave*/
+ int report_binlog_update(THD *thd, const char *log_file,my_off_t log_pos);
+
+ int dump_start(THD* thd,
+ const char *log_file,
+ my_off_t log_pos);
+
+ void dump_end(THD* thd);
+
+ /* Reserve space in the replication event packet header:
+ * . slave semi-sync off: 1 byte - (0)
+ * . slave semi-sync on: 3 byte - (0, 0xef, 0/1}
+ *
+ * Input:
+ * packet - (IN) the header buffer
+ *
+ * Return:
+ * size of the bytes reserved for header
+ */
+ int reserve_sync_header(String* packet);
+
+ /* Update the sync bit in the packet header to indicate to the slave whether
+ * the master will wait for the reply of the event. If semi-sync is switched
+ * off and we detect that the slave is catching up, we switch semi-sync on.
+ *
+ * Input:
+ * THD - (IN) current dump thread
+ * packet - (IN) the packet containing the replication event
+ * log_file_name - (IN) the event ending position's file name
+ * log_file_pos - (IN) the event ending position's file offset
+ * need_sync - (IN) identify if flush_net is needed to call.
+ * server_id - (IN) master server id number
+ *
+ * Return:
+ * 0: success; non-zero: error
+ */
+ int update_sync_header(THD* thd, unsigned char *packet,
+ const char *log_file_name,
+ my_off_t log_file_pos,
+ bool* need_sync);
+
+ /* Called when a transaction finished writing binlog events.
+ * . update the 'largest' transactions' binlog event position
+ * . insert the ending position in the active transaction list if
+ * semi-sync is on
+ *
+ * Input: (the transaction events' ending binlog position)
+ * log_file_name - (IN) transaction ending position's file name
+ * log_file_pos - (IN) transaction ending position's file offset
+ *
+ * Return:
+ * 0: success; non-zero: error
+ */
+ int write_tranx_in_binlog(const char* log_file_name, my_off_t log_file_pos);
+
+ /* Read the slave's reply so that we know how much progress the slave makes
+ * on receive replication events.
+ */
+ int flush_net(THD* thd, const char *event_buf);
+
+ /* Export internal statistics for semi-sync replication. */
+ void set_export_stats();
+
+ /* 'reset master' command is issued from the user and semi-sync need to
+ * go off for that.
+ */
+ int after_reset_master();
+
+ /*called before reset master*/
+ int before_reset_master();
+
+ void check_and_switch();
+
+ mysql_mutex_t LOCK_rpl_semi_sync_master_enabled;
+};
+
+enum rpl_semi_sync_master_wait_point_t {
+ SEMI_SYNC_MASTER_WAIT_POINT_AFTER_BINLOG_SYNC,
+ SEMI_SYNC_MASTER_WAIT_POINT_AFTER_STORAGE_COMMIT,
+};
+
+extern Repl_semi_sync_master repl_semisync_master;
+extern Ack_receiver ack_receiver;
+
+/* System and status variables for the master component */
+extern my_bool rpl_semi_sync_master_enabled;
+extern my_bool rpl_semi_sync_master_status;
+extern ulong rpl_semi_sync_master_wait_point;
+extern ulong rpl_semi_sync_master_clients;
+extern ulong rpl_semi_sync_master_timeout;
+extern ulong rpl_semi_sync_master_trace_level;
+extern ulong rpl_semi_sync_master_yes_transactions;
+extern ulong rpl_semi_sync_master_no_transactions;
+extern ulong rpl_semi_sync_master_off_times;
+extern ulong rpl_semi_sync_master_wait_timeouts;
+extern ulong rpl_semi_sync_master_timefunc_fails;
+extern ulong rpl_semi_sync_master_num_timeouts;
+extern ulong rpl_semi_sync_master_wait_sessions;
+extern ulong rpl_semi_sync_master_wait_pos_backtraverse;
+extern ulong rpl_semi_sync_master_avg_trx_wait_time;
+extern ulong rpl_semi_sync_master_avg_net_wait_time;
+extern ulonglong rpl_semi_sync_master_net_wait_num;
+extern ulonglong rpl_semi_sync_master_trx_wait_num;
+extern ulonglong rpl_semi_sync_master_net_wait_time;
+extern ulonglong rpl_semi_sync_master_trx_wait_time;
+extern unsigned long long rpl_semi_sync_master_request_ack;
+extern unsigned long long rpl_semi_sync_master_get_ack;
+
+/*
+ This indicates whether we should keep waiting if no semi-sync slave
+ is available.
+ 0 : stop waiting if detected no avaialable semi-sync slave.
+ 1 (default) : keep waiting until timeout even no available semi-sync slave.
+*/
+extern char rpl_semi_sync_master_wait_no_slave;
+extern Repl_semi_sync_master repl_semisync_master;
+
+extern PSI_stage_info stage_waiting_for_semi_sync_ack_from_slave;
+extern PSI_stage_info stage_reading_semi_sync_ack;
+extern PSI_stage_info stage_waiting_for_semi_sync_slave;
+
+void semi_sync_master_deinit();
+
+#endif /* SEMISYNC_MASTER_H */
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