Inconsistency with lengths of Example and Fingerprints in Query Analytics

PMM should set some reasonable limits of the query lengths as it takes queries from external data source.   Currently I for MySQL using slow query log this:

6bc4a70713eb :) select max(length(fingerprint)),max(length(example)) from metrics;

SELECT
 max(length(fingerprint)),
 max(length(example))
FROM metrics

┌─max(length(fingerprint))─┬─max(length(example))─┐
│ 563345                   │ 1024                 │
└──────────────────────────┴──────────────────────┘

1 rows in set. Elapsed: 0.722 sec. Processed 3.48 million rows, 634.45 MB (4.82 million rows/s., 878.31 MB/s.)

 Storing 500K fingerprint is impractical, for example from standpoint of showing it in UI

 We already truncate example....  if anything there is more harm truncating example as it makes EXPLAIN non functional.

 This data is from MySQL/Slow Query Log.  Some data sources like Performance Schema enforce their own max length of stored query and do truncation

Suggested fix:

• use the same max length of fingerprint as for query example.