hi, all:
when I take a backup from standby node,it report "WARNING: Could not read WAL record at 1/4D000148: invalid record length at 1/4D000148: wanted 24, got 0" many times,
and finaly the backup seems finish succesfully,why it throws so many WARNNING message?

[postgres@pg2 admsh]$ pg_probackup backup -B /home/postgres/bak --instance local_5432 -b full --threads=4 --progress --stream
INFO: Backup start, pg_probackup version: 2.4.15, instance: local_5432, backup ID: R0DRL3, backup mode: FULL, wal mode: STREAM, remote: false, compress-algorithm: zlib, compress-level: 5
WARNING: This PostgreSQL instance was initialized without data block checksums. pg_probackup have no way to detect data block corruption without them. Reinitialize PGDATA with option '--data-checksums'.
WARNING: Current PostgreSQL role is superuser. It is not recommended to run backup or checkdb as superuser.
INFO: Backup R0DRL3 is going to be taken from standby
INFO: wait for pg_start_backup()
INFO: Wait for WAL segment /home/postgres/bak/backups/local_5432/R0DRL3/database/pg_wal/00000005000000010000004D to be streamed
INFO: PGDATA size: 2878MB
INFO: Start transferring data files
INFO: Progress: (1/1262). Process file "base/1/4147"
INFO: Progress: (3/1262). Process file "global/4185"
.....repeat ....
INFO: Progress: (1261/1262). Process file "base/16385/24601"
INFO: Progress: (1262/1262). Process file "core.20734"
INFO: Data files are transferred, time elapsed: 14s
INFO: wait for pg_stop_backup()
INFO: pg_stop backup() successfully executed
WARNING: Could not read WAL record at 1/4D000148: invalid record length at 1/4D000148: wanted 24, got 0
INFO: Wait for LSN 1/4D000148 in streamed WAL segment /home/postgres/bak/backups/local_5432/R0DRL3/database/pg_wal/00000005000000010000004D
WARNING: Could not read WAL record at 1/4D000148: invalid record length at 1/4D000148: wanted 24, got 0
WARNING: Could not read WAL record at 1/4D000148: invalid record length at 1/4D000148: wanted 24, got 0
....repeat N time
WARNING: Could not read WAL record at 1/4D000148: invalid record length at 1/4D000148: wanted 24, got 0
WARNING: Could not read WAL record at 1/4D000148: invalid record length at 1/4D000148: wanted 24, got 0
INFO: Syncing backup files to disk
INFO: Backup files are synced, time elapsed: 0
INFO: Validating backup R0DRL3
INFO: Progress: (1/1266). Validate file "base/1/4147"
INFO: Progress: (2/1266). Validate file "base/1/4149"
....
INFO: Progress: (1263/1266). Validate file "backup_label"
INFO: Progress: (1264/1266). Validate file "pg_wal/00000005000000010000004D"
INFO: Progress: (1265/1266). Validate file "pg_wal/00000005.history"
INFO: Progress: (1266/1266). Validate file "database_map"
INFO: Backup R0DRL3 data files are valid
INFO: Backup R0DRL3 resident size: 2394MB
INFO: Backup R0DRL3 completed