MF-1361 - Add StringValue and DataValue comparison filters

[fthdrmzzz]

What does this do?

This pull request adds le le lt ge gt comparators for StringValue and DataValue

Which issue(s) does this PR fix/relate to?

Resolves #1361

List any changes that modify/break current functionality

There are no breaking changes. Now StringValue and DataValue comparisons are possible in database readers.

Have you included tests for your changes?

Yes, test cases are added.

Did you document any new/modified functionality?

No.

Notes

N/A

[dborovcanin]

@fthdrmzzz Please add these comparators for all the readers. Having them case-sensitive looks OK. Eventually, we can add a flag or indication if we want case sensitive or not, but this is good enough for the first iteration.

[codecov-commenter]

Codecov Report

Merging #1573 (4ab0a5f) into master (127044e) will increase coverage by 0.01%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1573      +/-   ##
==========================================
+ Coverage   68.93%   68.94%   +0.01%     
==========================================
  Files         136      136              
  Lines       11044    11048       +4     
==========================================
+ Hits         7613     7617       +4     
  Misses       2784     2784              
  Partials      647      647              

Impacted Files	Coverage Δ
readers/cassandra/messages.go	82.40% <100.00%> (+0.33%)	:arrow_up:
readers/postgres/messages.go	85.57% <100.00%> (+0.28%)	:arrow_up:

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[fthdrmzzz]

For String Comparison, in InfluxQL = comparator works but <=, <, >, >= comparators do not work. Does InfluxQL not support these comparators for strings?

There is string comparison in Flux.

[fthdrmzzz]

I wont be able to work on this pull request for a while. I am planning to continue after 2-3 weeks

[dborovcanin]

@fthdrmzzz Please add these comparators for all the readers. Having them case-sensitive looks OK. Eventually, we can add a flag or indication if we want case sensitive or not, but this is good enough for the first iteration.

@fthdrmzzz Do you plan on continuing work on this PR and addressing this remark (implementation and tests for InfluxDB and TimescaleDB are missing)? If not, let us know so someone else can take over. This is a nice and useful feature and it would be a good contribution.

[fthdrmzzz]

@fthdrmzzz Please add these comparators for all the readers. Having them case-sensitive looks OK. Eventually, we can add a flag or indication if we want case sensitive or not, but this is good enough for the first iteration.

@fthdrmzzz Do you plan on continuing work on this PR and addressing this remark (implementation and tests for InfluxDB and TimescaleDB are missing)? If not, let us know so someone else can take over. This is a nice and useful feature and it would be a good contribution.

This PR is waiting for PR MF-1584 to be merged. This pr cannot continue without the update on MF 1584

[drasko]

Merged via #1714