From a81d25c489d1f0d032fe7d102d130de7446f140d Mon Sep 17 00:00:00 2001
From: Daniel Nichter <daniel@percona.com>
Date: Mon, 26 Mar 2012 10:45:46 -0600
Subject: [PATCH] Add fingerprint_md5 and preserve_embedded_numbers flags to
 QueryRewriter, used in fingerprint() to handle customer's requirements.

---
 lib/QueryRewriter.pm  | 28 +++++++++++++++++---
 t/lib/QueryRewriter.t | 60 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/lib/QueryRewriter.pm b/lib/QueryRewriter.pm
index b89ea1c6..1789e634 100644
--- a/lib/QueryRewriter.pm
+++ b/lib/QueryRewriter.pm
@@ -175,10 +175,30 @@ sub fingerprint {
    $query =~ s/\\["']//g;                # quoted strings
    $query =~ s/".*?"/?/sg;               # quoted strings
    $query =~ s/'.*?'/?/sg;               # quoted strings
-   # This regex is extremely broad in its definition of what looks like a
-   # number.  That is for speed.
-   $query =~ s/[0-9+-][0-9a-f.xb+-]*/?/g;# Anything vaguely resembling numbers
-   $query =~ s/[xb.+-]\?/?/g;            # Clean up leftovers
+
+   # MD5 checksums which are always 32 hex chars 
+   if ( $self->{fingerprint_md5} ) { 
+      $query =~ s/([._-])[a-f0-9]{32}/$1?/g;
+   }
+
+   # Things resembling numbers/hex.
+   if ( !$self->{preserve_embedded_numbers} ) {
+      # For speed, this regex is extremely broad in its definition
+      # of what looks like a number.
+      $query =~ s/[0-9+-][0-9a-f.xb+-]*/?/g;
+   }
+   else {
+      $query =~ s/\b[0-9+-][0-9a-f.xb+-]*/?/g;
+   }
+
+   # Clean up leftovers
+   if ( $self->{fingerprint_md5} ) {
+      $query =~ s/[xb+-]\?/?/g;                
+   }
+   else {
+      $query =~ s/[xb.+-]\?/?/g;
+   }
+
    $query =~ s/\A\s+//;                  # Chop off leading whitespace
    chomp $query;                         # Kill trailing whitespace
    $query =~ tr[ \n\t\r\f][ ]s;          # Collapse whitespace
diff --git a/t/lib/QueryRewriter.t b/t/lib/QueryRewriter.t
index c60f6dce..d2fa4e97 100644
--- a/t/lib/QueryRewriter.t
+++ b/t/lib/QueryRewriter.t
@@ -10,7 +10,7 @@ BEGIN {
 use strict;
 use warnings FATAL => 'all';
 use English qw(-no_match_vars);
-use Test::More tests => 266;
+use Test::More tests => 271;
 
 use QueryRewriter;
 use QueryParser;
@@ -349,6 +349,64 @@ is(
    "Fingerprint LOAD DATA INFILE"
 );
 
+# fingerprint MD5 checksums, 32 char hex strings.  This is a
+# special feature used by pt-fingerprint.
+$qr = new QueryRewriter(
+   QueryParser     => $qp,
+   fingerprint_md5 => 1,
+);
+
+is(
+   $qr->fingerprint(
+      "SELECT * FROM db.fbc5e685a5d3d45aa1d0347fdb7c4d35_temp where id=1"
+   ),
+   "select * from db.?_temp where id=?",
+   "Fingerprint db.MD5_tbl"
+);
+
+is(
+   $qr->fingerprint(
+      "SELECT * FROM db.temp_fbc5e685a5d3d45aa1d0347fdb7c4d35 where id=1"
+   ),
+   "select * from db.temp_? where id=?",
+   "Fingerprint db.tbl_MD5"
+);
+
+$qr = new QueryRewriter(
+   QueryParser     => $qp,
+   fingerprint_md5 => 1,
+   preserve_embedded_numbers => 1,
+);
+
+is(
+   $qr->fingerprint(
+      "SELECT * FROM db.fbc5e685a5d3d45aa1d0347fdb7c4d35_temp where id=1"
+   ),
+   "select * from db.?_temp where id=?",
+   "Fingerprint db.MD5_tbl (with preserve_embedded_numbers)"
+);
+
+is(
+   $qr->fingerprint(
+      "SELECT * FROM db.temp_fbc5e685a5d3d45aa1d0347fdb7c4d35 where id=1"
+   ),
+   "select * from db.temp_? where id=?",
+   "Fingerprint db.tbl_MD5 (with preserve_embedded_numbers)"
+);
+
+$qr = new QueryRewriter(
+   QueryParser => $qp,
+   preserve_embedded_numbers => 1,
+);
+
+is(
+   $qr->fingerprint(
+      "SELECT * FROM prices.rt_5min where id=1"
+   ),
+   "select * from prices.rt_5min where id=?",
+   "Fingerprint db.tbl<number>name (preserve number)"
+);
+
 # #############################################################################
 # convert_to_select()
 # #############################################################################