MySQL :: MySQL 8.0 Reference Manual :: 22.4.22 ndb_redo_log_reader — Check and Print Content of Cluster Redo Log

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22.4.22 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.

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 22.4.31, “Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs”.

Table 22.349 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.

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

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

Property	Value
Command-Line Format	`--help`

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

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

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

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

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

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

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

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

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

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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