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MySQL 8.0 Reference Manual  /  ...  /  ndb_redo_log_reader — Check and Print Content of Cluster Redo Log

22.4.23 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.

Note

Prior to NDB 7.2, this utility was named ndbd_redo_log_reader.

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

The following table includes options that are specific to the NDB Cluster program ndb_redo_log_reader. Additional descriptions follow the table. For options common to most NDB Cluster programs (including ndb_redo_log_reader), see Section 22.4.32, “Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs”.

Table 22.336 Command-line options for the ndb_redo_log_reader program

Format Description Added, Deprecated, or Removed

-dump

Print dump info

All NDB 8.0 releases

-filedescriptors

Print file descriptors only

All NDB 8.0 releases

--help

Print usage information

All NDB 8.0 releases

-lap

Provide lap info, with max GCI started and completed

All NDB 8.0 releases

-mbyte #

Starting megabyte

All NDB 8.0 releases

-mbyteheaders

Show only the first page header of every megabyte in the file

All NDB 8.0 releases

-nocheck

Do not check records for errors

All NDB 8.0 releases

-noprint

Do not print records

All NDB 8.0 releases

-page #

Start with this page

All NDB 8.0 releases

-pageheaders

Show page headers only

All NDB 8.0 releases

-pageindex #

Start with this page index

All NDB 8.0 releases

-twiddle

Bit-shifted dump

All NDB 8.0 releases


Usage

ndb_redo_log_reader file_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 pattern ndb_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 following D is in the range 8-39 inclusive; the range of the number following S varies according to the value of the NoOfFragmentLogFiles 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, see NDB Cluster Data Node File System Directory Files.

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

  • -dump

    Property Value
    Command-Line Format -dump
    Type Boolean
    Default Value FALSE

    Print dump info.

  • Property Value
    Command-Line Format -filedescriptors
    Type Boolean
    Default Value FALSE

    -filedescriptors: Print file descriptors only.

  • Property Value
    Command-Line Format --help

    --help: Print usage information.

  • -lap

    Property Value
    Command-Line Format -lap
    Type Boolean
    Default Value FALSE

    Provide lap info, with max GCI started and completed.

  • Property Value
    Command-Line Format -mbyte #
    Type Numeric
    Default Value 0
    Minimum Value 0
    Maximum Value 15

    -mbyte #: Starting megabyte.

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

  • Property Value
    Command-Line Format -mbyteheaders
    Type Boolean
    Default Value FALSE

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

  • Property Value
    Command-Line Format -noprint
    Type Boolean
    Default Value FALSE

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

  • Property Value
    Command-Line Format -nocheck
    Type Boolean
    Default Value FALSE

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

  • Property Value
    Command-Line Format -page #
    Type Integer
    Default Value 0
    Minimum Value 0
    Maximum Value 31

    -page #: Start at this page.

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

  • Property Value
    Command-Line Format -pageheaders
    Type Boolean
    Default Value FALSE

    -pageheaders: Show page headers only.

  • Property Value
    Command-Line Format -pageindex #
    Type Integer
    Default Value 12
    Minimum Value 12
    Maximum Value 8191

    -pageindex #: Start at this page index.

    # is an integer between 12 and 8191, inclusive.

  • -twiddle

    Property Value
    Command-Line Format -twiddle
    Type Boolean
    Default Value FALSE

    Bit-shifted dump.

Like ndb_print_backup_file and ndb_print_schema_file (and unlike most of the NDB 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.


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