18.4.21 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 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 18.4.29, “Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs”.

Table 18.31 Command-line options for the ndb_redo_log_reader program

Format	Description	Added, Deprecated, or Removed
`-dump`	Print dump info	(Supported in all MySQL 5.6 based releases)
`-filedescriptors`	Print file descriptors only	(Supported in all MySQL 5.6 based releases)
`--help`	Print usage information	ADDED: NDB 7.3.4
`-lap`	Provide lap info, with max GCI started and completed	(Supported in all MySQL 5.6 based releases)
`-mbyte #`	Starting megabyte	(Supported in all MySQL 5.6 based releases)
`-mbyteheaders`	Show only first page header of each megabyte in file	(Supported in all MySQL 5.6 based releases)
`-nocheck`	Do not check records for errors	(Supported in all MySQL 5.6 based releases)
`-noprint`	Do not print records	(Supported in all MySQL 5.6 based releases)
`-page #`	Start with this page	(Supported in all MySQL 5.6 based releases)
`-pageheaders`	Show page headers only	(Supported in all MySQL 5.6 based releases)
`-pageindex #`	Start with this page index	(Supported in all MySQL 5.6 based releases)
`-twiddle`	Bit-shifted dump	(Supported in all MySQL 5.6 based 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.

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
Type Boolean
Default Value FALSE
Print dump info.
Command-Line Format -filedescriptors
Type Boolean
Default Value FALSE
-filedescriptors: Print file descriptors only.
Command-Line Format --help
Introduced 5.6.15-ndb-7.3.4
--help: Print usage information.
Added in NDB 7.3.4. (Bug #11749591, Bug #36805)
-lap
Command-Line Format -lap
Type Boolean
Default Value FALSE
Provide lap info, with max GCI started and completed.
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.
Command-Line Format -mbyteheaders
Type Boolean
Default Value FALSE
-mbyteheaders: Show only the first page header of every megabyte in the file.
Command-Line Format -noprint
Type Boolean
Default Value FALSE
-noprint: Do not print the contents of the log file.
Command-Line Format -nocheck
Type Boolean
Default Value FALSE
-nocheck: Do not check the log file for errors.
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.
Command-Line Format -pageheaders
Type Boolean
Default Value FALSE
-pageheaders: Show page headers only.
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
Command-Line Format -twiddle
Type Boolean
Default Value FALSE
Bit-shifted dump.

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

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

Command-Line Format	`--help`
Introduced	5.6.15-ndb-7.3.4

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

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

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

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

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

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

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

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

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.