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PT-187 Updated documentation for pt-table-checksum

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Added info & links regarding the use of CRC32 as the checksum algorithm.
This commit is contained in:
Carlos Salguero
2017-09-19 14:58:26 -03:00
parent b8067ad5b3
commit 794999154c
1 changed files with 9 additions and 0 deletions
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bin/pt-table-checksum
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@@ -11845,6 +11845,15 @@ can try something like the following:
SET boundaries = COALESCE(CONCAT('id BETWEEN ', lower_boundary,
' AND ', upper_boundary), '1=1');
Take into consideration that by default, pt-table-checksum use C<CRC32> checksums.
C<CRC32> is not a cryptographic algorithm and for that reason it is prone to have
collisions. On the other hand, C<CRC32> algorithm is faster and less CPU-intensive
than C<MD5> and C<SHA1>.
Related reading material:
Percona Toolkit UDFs: L<https://www.percona.com/doc/percona-server/LATEST/management/udf_percona_toolkit.html>
How to avoid hash collisions when using MySQL’s CRC32 function: L<https://www.percona.com/blog/2014/10/13/how-to-avoid-hash-collisions-when-using-mysqls-crc32-function/>
=head1 LIMITATIONS
=over