/* Copyright (c) 2013, Kristian Nielsen and MariaDB Services Ab. 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 02110-1301 USA */ #ifndef RPL_GTID_H #define RPL_GTID_H #include "hash.h" #include "queues.h" /* Definitions for MariaDB global transaction ID (GTID). */ extern const LEX_STRING rpl_gtid_slave_state_table_name; class String; struct rpl_gtid { uint32 domain_id; uint32 server_id; uint64 seq_no; }; enum enum_gtid_skip_type { GTID_SKIP_NOT, GTID_SKIP_STANDALONE, GTID_SKIP_TRANSACTION }; /* Structure to keep track of threads waiting in MASTER_GTID_WAIT(). Since replication is (mostly) single-threaded, we want to minimise the performance impact on that from MASTER_GTID_WAIT(). To achieve this, we are careful to keep the common lock between replication threads and MASTER_GTID_WAIT threads held for as short as possible. We keep only a single thread waiting to be notified by the replication threads; this thread then handles all the (potentially heavy) lifting of dealing with all current waiting threads. */ struct gtid_waiting { /* Elements in the hash, basically a priority queue for each domain. */ struct hash_element { QUEUE queue; uint32 domain_id; }; /* A priority queue to handle waiters in one domain in seq_no order. */ struct queue_element { uint64 wait_seq_no; THD *thd; int queue_idx; /* do_small_wait is true if we have responsibility for ensuring that there is a small waiter. */ bool do_small_wait; /* The flag `done' is set when the wait is completed (either due to reaching the position waited for, or due to timeout or kill). The queue_element is in the queue if and only if `done' is true. */ bool done; }; mysql_mutex_t LOCK_gtid_waiting; HASH hash; void init(); void destroy(); hash_element *get_entry(uint32 domain_id); int wait_for_pos(THD *thd, String *gtid_str, longlong timeout_us); void promote_new_waiter(gtid_waiting::hash_element *he); int wait_for_gtid(THD *thd, rpl_gtid *wait_gtid, struct timespec *wait_until); void process_wait_hash(uint64 wakeup_seq_no, gtid_waiting::hash_element *he); int register_in_wait_queue(THD *thd, rpl_gtid *wait_gtid, hash_element *he, queue_element *elem); void remove_from_wait_queue(hash_element *he, queue_element *elem); }; /* Replication slave state. For every independent replication stream (identified by domain_id), this remembers the last gtid applied on the slave within this domain. Since events are always committed in-order within a single domain, this is sufficient to maintain the state of the replication slave. */ struct rpl_slave_state { /* Elements in the list of GTIDs kept for each domain_id. */ struct list_element { struct list_element *next; uint64 sub_id; uint64 seq_no; uint32 server_id; }; /* Elements in the HASH that hold the state for one domain_id. */ struct element { struct list_element *list; uint32 domain_id; /* Highest seq_no seen so far in this domain. */ uint64 highest_seq_no; /* If this is non-NULL, then it is the waiter responsible for the small wait in MASTER_GTID_WAIT(). */ gtid_waiting::queue_element *gtid_waiter; /* If gtid_waiter is non-NULL, then this is the seq_no that its MASTER_GTID_WAIT() is waiting on. When we reach this seq_no, we need to signal the waiter on COND_wait_gtid. */ uint64 min_wait_seq_no; mysql_cond_t COND_wait_gtid; list_element *grab_list() { list_element *l= list; list= NULL; return l; } void add(list_element *l) { l->next= list; list= l; } }; /* Mapping from domain_id to its element. */ HASH hash; /* Mutex protecting access to the state. */ mysql_mutex_t LOCK_slave_state; uint64 last_sub_id; bool inited; bool loaded; rpl_slave_state(); ~rpl_slave_state(); void init(); void deinit(); void truncate_hash(); ulong count() const { return hash.records; } int update(uint32 domain_id, uint32 server_id, uint64 sub_id, uint64 seq_no); int truncate_state_table(THD *thd); int record_gtid(THD *thd, const rpl_gtid *gtid, uint64 sub_id, bool in_transaction, bool in_statement); uint64 next_sub_id(uint32 domain_id); int iterate(int (*cb)(rpl_gtid *, void *), void *data, rpl_gtid *extra_gtids, uint32 num_extra); int tostring(String *dest, rpl_gtid *extra_gtids, uint32 num_extra); bool domain_to_gtid(uint32 domain_id, rpl_gtid *out_gtid); int load(THD *thd, char *state_from_master, size_t len, bool reset, bool in_statement); bool is_empty(); element *get_element(uint32 domain_id); int put_back_list(uint32 domain_id, list_element *list); void update_state_hash(uint64 sub_id, rpl_gtid *gtid); int record_and_update_gtid(THD *thd, struct rpl_group_info *rgi); }; /* Binlog state. This keeps the last GTID written to the binlog for every distinct (domain_id, server_id) pair. This will be logged at the start of the next binlog file as a Gtid_list_log_event; this way, it is easy to find the binlog file containing a gigen GTID, by simply scanning backwards from the newest one until a lower seq_no is found in the Gtid_list_log_event at the start of a binlog for the given domain_id and server_id. We also remember the last logged GTID for every domain_id. This is used to know where to start when a master is changed to a slave. As a side effect, it also allows to skip a hash lookup in the very common case of logging a new GTID with same server id as last GTID. */ struct rpl_binlog_state { struct element { uint32 domain_id; HASH hash; /* Containing all server_id for one domain_id */ /* The most recent entry in the hash. */ rpl_gtid *last_gtid; /* Counter to allocate next seq_no for this domain. */ uint64 seq_no_counter; int update_element(const rpl_gtid *gtid); }; /* Mapping from domain_id to collection of elements. */ HASH hash; /* Mutex protecting access to the state. */ mysql_mutex_t LOCK_binlog_state; my_bool initialized; rpl_binlog_state(); ~rpl_binlog_state(); void reset_nolock(); void reset(); void free(); bool load(struct rpl_gtid *list, uint32 count); int update_nolock(const struct rpl_gtid *gtid, bool strict); int update(const struct rpl_gtid *gtid, bool strict); int update_with_next_gtid(uint32 domain_id, uint32 server_id, rpl_gtid *gtid); int alloc_element_nolock(const rpl_gtid *gtid); bool check_strict_sequence(uint32 domain_id, uint32 server_id, uint64 seq_no); int bump_seq_no_if_needed(uint32 domain_id, uint64 seq_no); int write_to_iocache(IO_CACHE *dest); int read_from_iocache(IO_CACHE *src); uint32 count(); int get_gtid_list(rpl_gtid *gtid_list, uint32 list_size); int get_most_recent_gtid_list(rpl_gtid **list, uint32 *size); bool append_pos(String *str); bool append_state(String *str); rpl_gtid *find_nolock(uint32 domain_id, uint32 server_id); rpl_gtid *find(uint32 domain_id, uint32 server_id); rpl_gtid *find_most_recent(uint32 domain_id); }; /* Represent the GTID state that a slave connection to a master requests the master to start sending binlog events from. */ struct slave_connection_state { struct entry { rpl_gtid gtid; uint32 flags; }; static const uint32 START_OWN_SLAVE_POS= 0x1; static const uint32 START_ON_EMPTY_DOMAIN= 0x2; /* Mapping from domain_id to the entry with GTID requested for that domain. */ HASH hash; slave_connection_state(); ~slave_connection_state(); void reset() { my_hash_reset(&hash); } int load(char *slave_request, size_t len); int load(const rpl_gtid *gtid_list, uint32 count); int load(rpl_slave_state *state, rpl_gtid *extra_gtids, uint32 num_extra); rpl_gtid *find(uint32 domain_id); entry *find_entry(uint32 domain_id); int update(const rpl_gtid *in_gtid); void remove(const rpl_gtid *gtid); void remove_if_present(const rpl_gtid *in_gtid); ulong count() const { return hash.records; } int to_string(String *out_str); int append_to_string(String *out_str); int get_gtid_list(rpl_gtid *gtid_list, uint32 list_size); }; extern bool rpl_slave_state_tostring_helper(String *dest, const rpl_gtid *gtid, bool *first); extern int gtid_check_rpl_slave_state_table(TABLE *table); extern rpl_gtid *gtid_parse_string_to_list(const char *p, size_t len, uint32 *out_len); #endif /* RPL_GTID_H */