src/include/replication/logicalproto.h

/*-------------------------------------------------------------------------
 *
 * logicalproto.h
 *		logical replication protocol
 *
 * Copyright (c) 2015-2021, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *		src/include/replication/logicalproto.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef LOGICAL_PROTO_H
#define LOGICAL_PROTO_H

#include "replication/reorderbuffer.h"
#include "utils/rel.h"

/*
 * Protocol capabilities
 *
 * LOGICALREP_PROTO_VERSION_NUM is our native protocol.
 * LOGICALREP_PROTO_MAX_VERSION_NUM is the greatest version we can support.
 * LOGICALREP_PROTO_MIN_VERSION_NUM is the oldest version we
 * have backwards compatibility for. The client requests protocol version at
 * connect time.
 *
 * LOGICALREP_PROTO_STREAM_VERSION_NUM is the minimum protocol version with
 * support for streaming large transactions.
 */
#define LOGICALREP_PROTO_MIN_VERSION_NUM 1
#define LOGICALREP_PROTO_VERSION_NUM 1
#define LOGICALREP_PROTO_STREAM_VERSION_NUM 2
#define LOGICALREP_PROTO_MAX_VERSION_NUM LOGICALREP_PROTO_STREAM_VERSION_NUM

/*
 * Logical message types
 *
 * Used by logical replication wire protocol.
 *
 * Note: though this is an enum, the values are used to identify message types
 * in logical replication protocol, which uses a single byte to identify a
 * message type. Hence the values should be single-byte wide and preferably
 * human-readable characters.
 */
typedef enum LogicalRepMsgType
{
	LOGICAL_REP_MSG_BEGIN = 'B',
	LOGICAL_REP_MSG_COMMIT = 'C',
	LOGICAL_REP_MSG_ORIGIN = 'O',
	LOGICAL_REP_MSG_INSERT = 'I',
	LOGICAL_REP_MSG_UPDATE = 'U',
	LOGICAL_REP_MSG_DELETE = 'D',
	LOGICAL_REP_MSG_TRUNCATE = 'T',
	LOGICAL_REP_MSG_RELATION = 'R',
	LOGICAL_REP_MSG_TYPE = 'Y',
	LOGICAL_REP_MSG_MESSAGE = 'M',
	LOGICAL_REP_MSG_STREAM_START = 'S',
	LOGICAL_REP_MSG_STREAM_END = 'E',
	LOGICAL_REP_MSG_STREAM_COMMIT = 'c',
	LOGICAL_REP_MSG_STREAM_ABORT = 'A'
} LogicalRepMsgType;

/*
 * This struct stores a tuple received via logical replication.
 * Keep in mind that the columns correspond to the *remote* table.
 */
typedef struct LogicalRepTupleData
{
	/* Array of StringInfos, one per column; some may be unused */
	StringInfoData *colvalues;
	/* Array of markers for null/unchanged/text/binary, one per column */
	char	   *colstatus;
	/* Length of above arrays */
	int			ncols;
} LogicalRepTupleData;

/* Possible values for LogicalRepTupleData.colstatus[colnum] */
/* These values are also used in the on-the-wire protocol */
#define LOGICALREP_COLUMN_NULL		'n'
#define LOGICALREP_COLUMN_UNCHANGED	'u'
#define LOGICALREP_COLUMN_TEXT		't'
#define LOGICALREP_COLUMN_BINARY	'b' /* added in PG14 */

typedef uint32 LogicalRepRelId;

/* Relation information */
typedef struct LogicalRepRelation
{
	/* Info coming from the remote side. */
	LogicalRepRelId remoteid;	/* unique id of the relation */
	char	   *nspname;		/* schema name */
	char	   *relname;		/* relation name */
	int			natts;			/* number of columns */
	char	  **attnames;		/* column names */
	Oid		   *atttyps;		/* column types */
	char		replident;		/* replica identity */
	char		relkind;		/* remote relation kind */
	Bitmapset  *attkeys;		/* Bitmap of key columns */
} LogicalRepRelation;

/* Type mapping info */
typedef struct LogicalRepTyp
{
	Oid			remoteid;		/* unique id of the remote type */
	char	   *nspname;		/* schema name of remote type */
	char	   *typname;		/* name of the remote type */
} LogicalRepTyp;

/* Transaction info */
typedef struct LogicalRepBeginData
{
	XLogRecPtr	final_lsn;
	TimestampTz committime;
	TransactionId xid;
} LogicalRepBeginData;

typedef struct LogicalRepCommitData
{
	XLogRecPtr	commit_lsn;
	XLogRecPtr	end_lsn;
	TimestampTz committime;
} LogicalRepCommitData;

extern void logicalrep_write_begin(StringInfo out, ReorderBufferTXN *txn);
extern void logicalrep_read_begin(StringInfo in,
								  LogicalRepBeginData *begin_data);
extern void logicalrep_write_commit(StringInfo out, ReorderBufferTXN *txn,
									XLogRecPtr commit_lsn);
extern void logicalrep_read_commit(StringInfo in,
								   LogicalRepCommitData *commit_data);
extern void logicalrep_write_origin(StringInfo out, const char *origin,
									XLogRecPtr origin_lsn);
extern char *logicalrep_read_origin(StringInfo in, XLogRecPtr *origin_lsn);
extern void logicalrep_write_insert(StringInfo out, TransactionId xid,
									Relation rel, HeapTuple newtuple,
									bool binary);
extern LogicalRepRelId logicalrep_read_insert(StringInfo in, LogicalRepTupleData *newtup);
extern void logicalrep_write_update(StringInfo out, TransactionId xid,
									Relation rel, HeapTuple oldtuple,
									HeapTuple newtuple, bool binary);
extern LogicalRepRelId logicalrep_read_update(StringInfo in,
											  bool *has_oldtuple, LogicalRepTupleData *oldtup,
											  LogicalRepTupleData *newtup);
extern void logicalrep_write_delete(StringInfo out, TransactionId xid,
									Relation rel, HeapTuple oldtuple,
									bool binary);
extern LogicalRepRelId logicalrep_read_delete(StringInfo in,
											  LogicalRepTupleData *oldtup);
extern void logicalrep_write_truncate(StringInfo out, TransactionId xid,
									  int nrelids, Oid relids[],
									  bool cascade, bool restart_seqs);
extern List *logicalrep_read_truncate(StringInfo in,
									  bool *cascade, bool *restart_seqs);
extern void logicalrep_write_message(StringInfo out, TransactionId xid, XLogRecPtr lsn,
									 bool transactional, const char *prefix, Size sz, const char *message);
extern void logicalrep_write_rel(StringInfo out, TransactionId xid,
								 Relation rel);
extern LogicalRepRelation *logicalrep_read_rel(StringInfo in);
extern void logicalrep_write_typ(StringInfo out, TransactionId xid,
								 Oid typoid);
extern void logicalrep_read_typ(StringInfo out, LogicalRepTyp *ltyp);
extern void logicalrep_write_stream_start(StringInfo out, TransactionId xid,
										  bool first_segment);
extern TransactionId logicalrep_read_stream_start(StringInfo in,
												  bool *first_segment);
extern void logicalrep_write_stream_stop(StringInfo out);
extern void logicalrep_write_stream_commit(StringInfo out, ReorderBufferTXN *txn,
										   XLogRecPtr commit_lsn);
extern TransactionId logicalrep_read_stream_commit(StringInfo out,
												   LogicalRepCommitData *commit_data);
extern void logicalrep_write_stream_abort(StringInfo out, TransactionId xid,
										  TransactionId subxid);
extern void logicalrep_read_stream_abort(StringInfo in, TransactionId *xid,
										 TransactionId *subxid);

#endif							/* LOGICAL_PROTO_H */