# pt-table-checksum "Deep recursion..." error

**URL:** https://forums.percona.com/t/pt-table-checksum-deep-recursion-error/2599
**Category:** Percona Toolkit
**Created:** [December 12, 2012, 10:28am UTC](https://forums.percona.com/t/pt-table-checksum-deep-recursion-error/2599 "2012-12-12T10:28:05Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![badaldudy](https://avatars.discourse-cdn.com/v4/letter/b/bb73d2/32.png) [@badaldudy](https://forums.percona.com/u/badaldudy)
#### Post date: [October 17, 2016, 8:07am UTC](https://forums.percona.com/t/pt-table-checksum-deep-recursion-error/2599/4 "2016-10-17T08:07:43Z")

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[QUOTE=niljoshi;9606]  
Hi,

hi i want to modify one column in the table and i alos want to use --recursion-method/ --check-slave-lag i want to monitor the lag between two network how can i do this

These are my commands:-

pt-online-schema-change --p=123456 --execute --check-slave-lag=10s h=abc.slave , P=3306 --print --alter “MODIFY COLUMN abc varchar(7) NOT NULL DEFAULT ‘money’” D=archives,t=abc\_details\_xyz;

pt-online-schema-change --p=123456 --execute --recursion-method=dsn=D=percona,t=dsns --print --alter “MODIFY COLUMN abc varchar(7) NOT NULL DEFAULT ‘money’” D=archives,t=abc\_details\_xyz;

These two are my errors:–

DBD::mysql::db selectcol\_arrayref failed: Unknown column ‘dsn’ in ‘field list’ [for Statement “SELECT dsn FROM `archives`.`abc_details_xyz` ORDER BY id”] at /usr/bin/pt-online-schema-change line 4764

Usage: pt-online-schema-change [OPTIONS] DSN

Errors in command-line arguments:

- Specify only one DSN on the command line
- The DSN must specify a database (D) and a table (t)

pt-online-schema-change alters a table’s structure without blocking reads or  
writes. Specify the database and table in the DSN. Do not use this tool before  
reading its documentation and checking your backups carefully. For more  
details, please use the --help option, or try ‘perldoc  
/usr/bin/pt-online-schema-change’ for complete documentation.

Please help on this topic you can contact me on [badal.singh&#64;cozygames.com](mailto:badal.singh&#64;cozygames.com)

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