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tbdv (Datafile Consistency Verification) Usage Guide

Document Type | Technical Information

Category | Administration

Applicable Product Versions | 6FS07PS, 7FS02PS

Document Number | TADTI007

 

Overview

tbdv is a utility that checks the consistency of Tibero data file blocks.
If dictionary table queries are not possible during operation or the database does not start normally, you can check the consistency of data file blocks at the block level.
 

tbdv Limitations

  • When using tbdv in an online state, DBWR may, with a low probability, mistakenly recognize a normal block as a corrupted block while writing the block.
  • In case of disk failure, even if the blocks where data is stored are zeroed out (initialized to 0), it is considered that the block format has not been done, so no error message is output.
  • Blocks loaded in Nologging mode are not detected by TBDV even if a failure occurs.
  • [IMS-98074] When using Raw Device, specifying the check size is required. (Option: -l <Raw Device Size>)
 
 

Method

How to Replace tbdv

Download from Technet and replace it in the $TB_HOME/client/bin directory for use.
 
  1. Access Tibero Technet - Technet > Download > Database > Tibero > Tibero Trouble Shooting Tools > Download
  2. Select Tibero Trouble Shooting Tools platform > Linux > Download tbdv
  3. Access Tibero server > navigate to the directory below, upload the downloaded file, and replace it
-. Backup existing file
$ cp $TB_HOME/client/bin/tbdv $TB_HOME/client/bin/tbdv.bak

-. Overwrite with new file
$ mv tbdv $TB_HOME/client/bin/
$ chmod +x $TB_HOME/client/bin/tbdv

 

How to Use tbdv

tbdv usage example for verifying data files.

$ tbdv [options] <datafile path>

-. Example
$ tbdv -s 8192 /path/to/datafile
$ tbdv
.==================================================================
.= Database Verifier (DV) starts                                  =
.=                                                                =
.= TmaxTibero Corporation Copyright (c) 2020-. All rights reserved. =
.==================================================================
Usage: tbdv [options] <fpath>
 <fpath>       path to datafile to verify

Options:
 -s    data block size (default: 8192)
 -m    multi block read count (default: 1)
 -l    the number of bytes to be checked
 -f    check if space management information is consistent. (default: 1)
Caution
When using Raw Device, the -l option is mandatory.
Example) tbdv '<datafile path>' -l <Raw Device size>

 

tbdv Options

Option
Description
-s
Block size (default: 8192 bytes)
-m
Number of blocks read at once from disk (default: 1)
-l
Specifies how many bytes from the beginning of the file to check (Default: check entire file). The minimum unit starts from K (e.g., 8K) -l {option value}/block size = number of blocks to check consistency for
-f
Performs consistency check on L1 bitmap block and calculates total count (default: 1)

 

tbdv Check Items 

When running tbdv, if the errors below are output, it is helpful to generate a dump of the corresponding block for easier root cause analysis.

  1. Check whether the data block is formatted
  2. Check the block's DBA (if it does not match, errors like below occur)
    block #<block_no> is misplaced dba differs (expected=<relative file id + blkno>, real= blkโ†’dba)
  3. Verify block's checksum consistency
    block #<block_no> isnโ€™t consistent.
  4. Check the block's free space
    block #<block_no> has incorrect freespace.
  5. When the block's Row-Piece areas overlap
    block #<block no> has overlapping or pieces.
 
 
 
 
 
 

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