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MySQL 9.5 Reference Manual  / ...  / MySQL NDB Cluster 9.5  / NDB Cluster Programs  /  ndb_redo_log_reader — Check and Print Content of Cluster Redo Log

25.5.22 ndb_redo_log_reader — Check and Print Content of Cluster Redo Log

Reads a redo log file, checking it for errors, printing its contents in a human-readable format, or both.ndb_redo_log_reader is intended for use primarily by NDB Cluster developers and Support personnel in debugging and diagnosing problems.

This utility remains under development, and its syntax and behavior are subject to change in future NDB Cluster releases.

The C++ source files forndb_redo_log_reader can be found in the directory/storage/ndb/src/kernel/blocks/dblqh/redoLogReader.

Options that can be used withndb_redo_log_reader are shown in the following table. Additional descriptions follow the table.

Usage

ndb_redo_log_readerfile_name [options]

file_name is the name of a cluster redo log file. redo log files are located in the numbered directories under the data node's data directory (DataDir); the path under this directory to the redo log files matches the patternndb_nodeid_fs/D#/DBLQH/S#.FragLog.nodeid is the data node's node ID. The two instances of# each represent a number (not necessarily the same number); the number followingD is in the range 8-39 inclusive; the range of the number followingS varies according to the value of theNoOfFragmentLogFiles configuration parameter, whose default value is 16; thus, the default range of the number in the file name is 0-15 inclusive. For more information, seeNDB Cluster Data Node File System Directory.

The name of the file to be read may be followed by one or more of the options listed here:

  • -dump

    Command-Line Format-dump

    Print dump info.

  • --file-key,-K

    Command-Line Format--file-key=key

    Supply file decryption key usingstdin,tty, or amy.cnf file.

  • --file-key-from-stdin

    Command-Line Format--file-key-from-stdin

    Supply file decryption key usingstdin.

  • Command-Line Format-filedescriptors

    -filedescriptors: Print file descriptors only.

  • Command-Line Format--help

    --help: Print usage information.

  • -lap

    Command-Line Format-lap

    Provide lap info, with max GCI started and completed.

  • Command-Line Format-mbyte #
    TypeNumeric
    Default Value0
    Minimum Value0
    Maximum Value15

    -mbyte#: Starting megabyte.

    # is an integer in the range 0 to 15, inclusive.

  • Command-Line Format-mbyteheaders

    -mbyteheaders: Show only the first page header of every megabyte in the file.

  • Command-Line Format-noprint

    -noprint: Do not print the contents of the log file.

  • Command-Line Format-nocheck

    -nocheck: Do not check the log file for errors.

  • Command-Line Format-page #
    TypeInteger
    Default Value0
    Minimum Value0
    Maximum Value31

    -page#: Start at this page.

    # is an integer in the range 0 to 31, inclusive.

  • Command-Line Format-pageheaders

    -pageheaders: Show page headers only.

  • Command-Line Format-pageindex #
    TypeInteger
    Default Value12
    Minimum Value12
    Maximum Value8191

    -pageindex#: Start at this page index.

    # is an integer between 12 and 8191, inclusive.

  • -twiddle

    Command-Line Format-twiddle

    Bit-shifted dump.

Likendb_print_backup_file andndb_print_schema_file (and unlike most of theNDB utilities that are intended to be run on a management server host or to connect to a management server)ndb_redo_log_reader must be run on a cluster data node, since it accesses the data node file system directly. Because it does not make use of the management server, this utility can be used when the management server is not running, and even when the cluster has been completely shut down.