Percona Toolkit moved to https://jira.percona.com/projects/PT

DBD::mysql bug causes pt-upgrade to use wrong precision (M) and scale (D)

Bug #926598 reported by Ovais Tariq on 2012-02-04

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	Percona Toolkit moved to https://jira.percona.com/projects/PT	Fix Released	Medium	Daniel Nichter	Percona Toolkit moved to https://jira.percona.com/projects/PT 2.0.4

Bug Description

The function that parses the result set to generate table structure used for comparing rows does not return the correct column definition for double/float data types. The definition of double/float column is returned as float|double(SCALE, PRECISION), while it should be float|double(PRECISION, SCALE).

In the following assignment:

$struct->{size}->{$col}
         = ($type =~ m/(?:float|double)/) ? "($s[$i],$p[$i])"
         : ($type =~ m/(?:decimal)/) ? "($p[$i],$s[$i])"
         : ($type =~ m/(?:char|varchar)/ && $p[$i]) ? "($p[$i])"

The line
= ($type =~ m/(?:float|double)/) ? "($s[$i],$p[$i])"

should be changed to
= ($type =~ m/(?:float|double)/) ? "($p[$i],$s[$i])"

Tags:

Related branches

lp:~percona-toolkit-dev/percona-toolkit/fix-md-bug-926598

Merged into lp:percona-toolkit/2.0 at revision 195

Daniel Nichter: Approve on 2012-03-02

Daniel Nichter (daniel-nichter) on 2012-02-07

Changed in percona-toolkit:
assignee:	nobody → Daniel Nichter (daniel-nichter)
importance:	Undecided → Medium
status:	New → In Progress
tags:	added: pt-upgrade wrong-sql

Revision history for this message

Daniel Nichter (daniel-nichter) wrote on 2012-02-07:

I think this a DBD::mysql bug or oddity because the code works as-is. You're correct, in theory, it should be (p,s) because according to http://dev.mysql.com/doc/refman/5.1/en/precision-math-decimal-changes.html p=m=precision and s=d=scale. Yet, on DBD::mysql 4.018 the results for two tests using a double column are correct: (7,2) and (31,23). Yet, on the same version of DBD::mysql, the order is correct for decimal types, (p,s), which again is tested and produces (31,12).

tags:

added: percona-21471

Revision history for this message

Daniel Nichter (daniel-nichter) wrote on 2012-02-07:

Key points from a conversation wit Ovais and Baron:

1. DBD::mysql has either one of two bugs: 1) it's scale and precicions are backwards for float|double, or 2) it produces values that are out of range. We don't know which is the case.

2. We can just ignore scale and precision altogether and create "col double" instead of "col double(m, d)".

tags:

added: dbd-mysql

Revision history for this message

Daniel Nichter (daniel-nichter) wrote on 2012-02-07:

See also bug 928271.

Changed in percona-toolkit:
milestone:	none → 2.0.4
summary:	- pt-upgrade: invalid column definition of float\|double datatype in - function MockSyncStream::get_result_set_struct + DBD::mysql bug causes pt-upgrade to use wrong precision (M) and scale + (D)

Daniel Nichter (daniel-nichter) on 2012-02-07

Changed in percona-toolkit:
status:	In Progress → Fix Committed

Daniel Nichter (daniel-nichter) on 2012-02-10

Changed in percona-toolkit:
status:	Fix Committed → Triaged

Daniel Nichter (daniel-nichter) on 2012-03-01

Changed in percona-toolkit:
status:	Triaged → In Progress

Daniel Nichter (daniel-nichter) on 2012-03-02

Changed in percona-toolkit:
status:	In Progress → Fix Committed

Daniel Nichter (daniel-nichter) on 2012-03-19

Changed in percona-toolkit:
status:	Fix Committed → Fix Released

Revision history for this message

Shahriyar Rzayev (rzayev-sehriyar) wrote on 2018-01-24:

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PT-462

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