multimaster.h

/*-------------------------------------------------------------------------
 *
 * mm.h
 *	General definitions
 *
 *
 * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *-------------------------------------------------------------------------
 */
#ifndef MULTIMASTER_H
#define MULTIMASTER_H

#include "postgres.h"

#include "storage/lwlock.h"
#include "storage/proc.h"
#include "access/xact.h"

#include "bgwpool.h"
#include "dmq.h"				/* DmqDestinationId */
#include "resolver.h"			/* XXX: rework message and get rid of this */

#define MULTIMASTER_SCHEMA_NAME          "mtm"
#define MULTIMASTER_NAME                 "multimaster"
#define MULTIMASTER_SLOT_PATTERN         "mtm_slot_%d"
/*  XXX: change to one NODENAME_FMT */
#define MTM_SUBNAME_FMT					 "mtm_sub_%d"
#define MTM_DMQNAME_FMT					 "node%d"
#define MULTIMASTER_FILTER_SLOT_PATTERN  "mtm_filter_slot_%d"
#define MULTIMASTER_LOCAL_TABLES_TABLE   "local_tables"
#define MULTIMASTER_MAX_CONN_STR_SIZE    128
#define MULTIMASTER_MAX_HOST_NAME_SIZE   64
#define MULTIMASTER_MAX_CTL_STR_SIZE     256
#define MULTIMASTER_BROADCAST_SERVICE    "mtm_broadcast"
#define MULTIMASTER_ADMIN                "mtm_admin"
#define MULTIMASTER_PRECOMMITTED         "precommitted"
#define MULTIMASTER_PREABORTED           "preaborted"

#define MTM_MAX_NODES 16

typedef uint64 nodemask_t;

#define LSN_FMT "%" INT64_MODIFIER "X"

#define MAX_NODES 64
#define BIT_CHECK(mask, bit) (((mask) & ((nodemask_t)1 << (bit))) != 0)
#define BIT_CLEAR(mask, bit) ((mask) &= ~((nodemask_t)1 << (bit)))
#define BIT_SET(mask, bit)   (mask |= ((nodemask_t)1 << (bit)))
#define ALL_BITS ((nodemask_t)~0)

#define EQUAL_GTID(x,y) ((x).node == (y).node && (x).xid == (y).xid)


/*
 * Definitions for the "mtm.cluster_nodes" table.
 */
#define MTM_NODES					"mtm.cluster_nodes"
#define Natts_mtm_nodes				4
#define Anum_mtm_nodes_id			1	/* node_id, same across cluster */
#define Anum_mtm_nodes_connifo		2	/* connection string */
#define Anum_mtm_nodes_is_self		3	/* is that tuple for our node? */

/*
 * Definitions for the "mtm.cluster_status" type.
 */
#define Natts_mtm_status					7
#define Anum_mtm_status_node_id				1
#define Anum_mtm_status_status				2
#define Anum_mtm_status_connected			3
#define Anum_mtm_status_gen_num				4
#define Anum_mtm_status_gen_members			5
#define Anum_mtm_status_gen_members_online	6
#define Anum_mtm_status_gen_configured		7

/*
 * Definitions for the "mtm.node_info" type.
 */
#define Natts_mtm_node_info					6
#define Anum_mtm_node_info_enabled			1
#define Anum_mtm_node_info_connected		2
#define Anum_mtm_node_info_sender_pid		3
#define Anum_mtm_node_info_receiver_pid		4
#define Anum_mtm_node_info_n_workers		5
#define Anum_mtm_node_info_receiver_mode	6


/* Identifier of global transaction */
typedef struct
{
	int			node;			/* One based id of node initiating transaction */
	TransactionId xid;			/* Transaction ID at origin node */
	TransactionId my_xid;		/* Transaction ID at our node */
} GlobalTransactionId;

typedef struct
{
	bool		contains_ddl;
	bool		contains_dml;
	bool		distributed;
} MtmCurrentTrans;

typedef struct MtmSeqPosition
{
	Oid			seqid;
	int64		next;
} MtmSeqPosition;

typedef enum
{
	PGLOGICAL_COMMIT,
	/* can be sent if prepared xact is aborted during decoding */
	PGLOGICAL_ABORT,
	PGLOGICAL_PREPARE,
	PGLOGICAL_COMMIT_PREPARED,
	PGLOGICAL_ABORT_PREPARED,
	PGLOGICAL_PREPARE_PHASE2A
}			PGLOGICAL_EVENT;


typedef struct
{
	Oid			sourceTable;
	nodemask_t	targetNodes;
} MtmCopyRequest;

#define MtmInvalidNodeId 0

typedef struct
{
	int			node_id;
	char	   *conninfo;
	RepOriginId origin_id;
	bool		init_done;
} MtmNode;

typedef struct
{
	int			n_nodes; /* num of entries in nodes[]. *Does* include myself. */
	int			my_node_id;
	int			backup_node_id;
	XLogRecPtr	backup_end_lsn;
	MtmNode		nodes[MTM_MAX_NODES];
	/*
	 * Some users prefer nodemask representation of nodes[]. Moreover, unlike
	 * nodes[] it *includes* myself.
	 */
	nodemask_t	mask;
} MtmConfig;

extern MtmConfig *receiver_mtm_cfg;
extern bool receiver_mtm_cfg_valid;

typedef struct
{
	LWLock	   *lock;
	LWLock	   *syncpoint_lock;

	/*
	 * We do not need to go into the database every time that we resolve
	 * deadlocks.
	 */
	bool		IsEnabled;
	Oid			DatabaseId;

	int			my_node_id;
	 /* configured members (initially + add/rm), maintained by monitor */
	pg_atomic_uint64 configured_mask;

	XLogRecPtr	latestSyncpoint;
	bool		localTablesHashLoaded;	/* Whether data from local_tables
										 * table is loaded in shared memory
										 * hash table */

	ConditionVariable receiver_barrier_cv;

	/*
	 * These 1) ensure that receiver in REPLMODE_RECOVERY excludes any other
	 * receiver (to avoid applying the same record twice). Counters are
	 * protected by Mtm->lock; it could be separate as well, but there is no
	 * contention.
	 */
	int nreceivers_recovery;
	int nreceivers_normal;

	pid_t		resolver_pid;

	struct
	{
		/*
		 * mode in which receiver is actually running (or has been running the
		 * last time it was alive)
		 */
		MtmReplicationMode receiver_mode;
		pid_t		walsender_pid;
		PGPROC		*walreceiver_proc;
		int			dmq_dest_id;
		pid_t		dmq_receiver_pid;
		/*
		 * which LSN we should ack to this node? caches get_recovery_horizon
		 */
		pg_atomic_uint64 horizon;
	}			peers[MTM_MAX_NODES];
	BgwPool		pools[MTM_MAX_NODES];	/* [Mtm->nAllNodes]: per-node data */

	/* for debugging/monitoring purposes */
	nodemask_t	walsenders_mask;
	nodemask_t	walreceivers_mask;

	bool	monitor_loaded;
	bool	replier_loaded;
} MtmShared;

extern MtmShared *Mtm;

/* XXX: to delete */
extern MtmCurrentTrans MtmTx;
extern int MtmTxAtxLevel;
extern MemoryContext MtmApplyContext;

/* bgworker identities */
extern bool MtmBackgroundWorker;
extern bool MtmIsLogicalReceiver;
extern bool MtmIsReceiver;
extern bool MtmIsPoolWorker;
extern bool MtmIsMonitorWorker;

/* GUCs */
extern int	MtmTransSpillThreshold;
extern int	MtmHeartbeatSendTimeout;
extern int	MtmHeartbeatRecvTimeout;
extern char *MtmRefereeConnStr;
#define IS_REFEREE_ENABLED() (MtmRefereeConnStr && *MtmRefereeConnStr)
extern int	MtmMaxWorkers;
extern bool MtmBreakConnection;
extern bool MtmWaitPeerCommits;
extern bool MtmNo3PC;
extern bool MtmBinaryBasetypes;

extern void MtmSleep(int64 interval);
extern TimestampTz MtmGetIncreasingTimestamp(void);
extern bool MtmAllApplyWorkersFinished(void);
extern MtmConfig *MtmLoadConfig(int elevel_on_absent);

typedef void (*mtm_cfg_change_cb) (int node_id, MtmConfig *new_cfg, Datum arg);

extern MtmConfig *MtmReloadConfig(MtmConfig *old_cfg,
								  mtm_cfg_change_cb node_add_cb,
								  mtm_cfg_change_cb node_drop_cb,
								  Datum arg,
								  int elevel_on_absent);
extern void MtmConfigFree(MtmConfig *cfg);
extern bool Quorum(int ntotal, int nvotes);
extern bool MtmQuorum(MtmConfig *mtm_cfg, int nvotes);
extern MtmNode *MtmNodeById(MtmConfig *cfg, int node_id);

extern bool MtmIsEnabled(void);

extern void MtmToggleReplication(void);

/* nodemask_t stuff */
extern int popcount(nodemask_t mask);
extern int first_set_bit(nodemask_t mask);
extern bool is_submask(nodemask_t submask, nodemask_t mask);
extern char *maskToString(nodemask_t mask);

struct MtmMessage; /* forward declaration for gather prototype */
typedef bool (*gather_hook_t)(struct MtmMessage *anymsg, Datum arg);
extern bool gather(nodemask_t participants,
				   struct MtmMessage **messages, int *senders, int *msg_count,
				   gather_hook_t msg_ok, Datum msg_ok_arg,
				   int *sendconn_cnt, uint64 gen_num);

/* boilerplate for config updates in bgws */
extern bool mtm_config_valid;
extern void mtm_pubsub_change_cb(Datum arg, int cacheid, uint32 hashvalue);
extern void mtm_attach_node(int node_id, MtmConfig *new_cfg, Datum arg);
extern void mtm_detach_node(int node_id, MtmConfig *new_cfg, Datum arg);

#endif							/* MULTIMASTER_H */