Enhance libpqrcv APIs to support slot synchronization.

This patch provides support for regular (non-replication) connections in
libpqrcv_connect(). This can be used to execute SQL statements on the
primary server without starting a walsender.

A new API libpqrcv_get_dbname_from_conninfo() is also added to extract the
database name from the given connection-info.

Note that this patch doesn't change any existing functionality but later
patches implementing the slot synchronization will use this functionality
to connect to the primary server to fetch required slot information.

Author: Shveta Malik, Hou Zhijie, Ajin Cherian
Reviewed-by: Peter Smith, Bertrand Drouvot, Dilip Kumar, Masahiko Sawada, Nisha Moond, Kuroda Hayato, Amit Kapila
Discussion: https://postgr.es/m/[email protected]

1 files changed, 17 insertions, 4 deletions

diff --git a/src/include/replication/walreceiver.h b/src/include/replication/walreceiver.h
index f566a99ba16..b906bb5ce83 100644
--- a/src/include/replication/walreceiver.h
+++ b/src/include/replication/walreceiver.h
@@ -228,8 +228,10 @@ typedef struct WalRcvExecResult
 /*
  * walrcv_connect_fn
  *
- * Establish connection to a cluster.  'logical' is true if the
- * connection is logical, and false if the connection is physical.
+ * Establish connection to a cluster.  'replication' is true if the
+ * connection is a replication connection, and false if it is a
+ * regular connection.  If it is a replication connection, it could
+ * be either logical or physical based on input argument 'logical'.
  * 'appname' is a name associated to the connection, to use for example
  * with fallback_application_name or application_name.  Returns the
  * details about the connection established, as defined by
@@ -237,6 +239,7 @@ typedef struct WalRcvExecResult
  * returned with 'err' including the error generated.
  */
 typedef WalReceiverConn *(*walrcv_connect_fn) (const char *conninfo,
+											   bool replication,
 											   bool logical,
 											   bool must_use_password,
 											   const char *appname,
@@ -280,6 +283,13 @@ typedef char *(*walrcv_identify_system_fn) (WalReceiverConn *conn,
 											TimeLineID *primary_tli);
 
 /*
+ * walrcv_get_dbname_from_conninfo_fn
+ *
+ * Returns the database name from the primary_conninfo
+ */
+typedef char *(*walrcv_get_dbname_from_conninfo_fn) (const char *conninfo);
+
+/*
  * walrcv_server_version_fn
  *
  * Returns the version number of the cluster connected to.
@@ -403,6 +413,7 @@ typedef struct WalReceiverFunctionsType
 	walrcv_get_conninfo_fn walrcv_get_conninfo;
 	walrcv_get_senderinfo_fn walrcv_get_senderinfo;
 	walrcv_identify_system_fn walrcv_identify_system;
+	walrcv_get_dbname_from_conninfo_fn walrcv_get_dbname_from_conninfo;
 	walrcv_server_version_fn walrcv_server_version;
 	walrcv_readtimelinehistoryfile_fn walrcv_readtimelinehistoryfile;
 	walrcv_startstreaming_fn walrcv_startstreaming;
@@ -418,8 +429,8 @@ typedef struct WalReceiverFunctionsType
 
 extern PGDLLIMPORT WalReceiverFunctionsType *WalReceiverFunctions;
 
-#define walrcv_connect(conninfo, logical, must_use_password, appname, err) \
-	WalReceiverFunctions->walrcv_connect(conninfo, logical, must_use_password, appname, err)
+#define walrcv_connect(conninfo, replication, logical, must_use_password, appname, err) \
+	WalReceiverFunctions->walrcv_connect(conninfo, replication, logical, must_use_password, appname, err)
 #define walrcv_check_conninfo(conninfo, must_use_password) \
 	WalReceiverFunctions->walrcv_check_conninfo(conninfo, must_use_password)
 #define walrcv_get_conninfo(conn) \
@@ -428,6 +439,8 @@ extern PGDLLIMPORT WalReceiverFunctionsType *WalReceiverFunctions;
 	WalReceiverFunctions->walrcv_get_senderinfo(conn, sender_host, sender_port)
 #define walrcv_identify_system(conn, primary_tli) \
 	WalReceiverFunctions->walrcv_identify_system(conn, primary_tli)
+#define walrcv_get_dbname_from_conninfo(conninfo) \
+	WalReceiverFunctions->walrcv_get_dbname_from_conninfo(conninfo)
 #define walrcv_server_version(conn) \
 	WalReceiverFunctions->walrcv_server_version(conn)
 #define walrcv_readtimelinehistoryfile(conn, tli, filename, content, size) \