Add root backup id for page/ptrack backups. issue #9

Author: stalkerg

backup.c

@@ -247,6 +247,9 @@ do_backup_database(parray *backup_list, pgBackupOption bkupopt)
 		lsn = &prev_backup->start_lsn;
 		elog(LOG, "backup only the page that there was of the update from LSN(%X/%08X)",
 			 (uint32) (*lsn >> 32), (uint32) *lsn);
+
+		current.parent_backup = prev_backup->start_time;
+		pgBackupWriteIni(&current);
 	}
 
 	/* initialize backup list */

catalog.c

@@ -294,6 +294,12 @@ pgBackupWriteResultSection(FILE *out, pgBackup *backup)
 	fprintf(out, "STREAM=%u\n", backup->stream);
 
 	fprintf(out, "STATUS=%s\n", status2str(backup->status));
+	if (backup->parent_backup != 0)
+	{
+		char *parent_backup = base36enc(backup->parent_backup);
+		fprintf(out, "PARENT_BACKUP='%s'\n", parent_backup);
+		free(parent_backup);
+	}
 }
 
 /* create backup.ini */
@@ -331,6 +337,7 @@ catalog_read_ini(const char *path)
 	char	   *start_lsn = NULL;
 	char	   *stop_lsn = NULL;
 	char	   *status = NULL;
+	char	   *parent_backup = NULL;
 	int			i;
 
 	pgut_option options[] =
@@ -349,6 +356,7 @@ catalog_read_ini(const char *path)
 		{'u', 0, "checksum_version",	NULL, SOURCE_ENV},
 		{'u', 0, "stream",				NULL, SOURCE_ENV},
 		{'s', 0, "status",				NULL, SOURCE_ENV},
+		{'s', 0, "parent_backup",		NULL, SOURCE_ENV},
 		{0}
 	};
 
@@ -373,6 +381,7 @@ catalog_read_ini(const char *path)
 	options[i++].var = &backup->checksum_version;
 	options[i++].var = &backup->stream;
 	options[i++].var = &status;
+	options[i++].var = &parent_backup;
 	Assert(i == lengthof(options) - 1);
 
 	pgut_readopt(path, options, ERROR);
@@ -428,6 +437,12 @@ catalog_read_ini(const char *path)
 		free(status);
 	}
 
+	if (parent_backup)
+	{
+		backup->parent_backup = base36dec(parent_backup);
+		free(parent_backup);
+	}
+
 	return backup;
 }
 
@@ -514,4 +529,5 @@ catalog_init_config(pgBackup *backup)
 	backup->recovery_time = (time_t) 0;
 	backup->data_bytes = BYTES_INVALID;
 	backup->stream = false;
+	backup->parent_backup = 0;
 }

pg_probackup.h

@@ -138,6 +138,7 @@ typedef struct pgBackup
 	uint32			wal_block_size;
 	uint32			checksum_version;
 	bool			stream;
+	time_t			parent_backup;
 } pgBackup;
 
 typedef struct pgBackupOption