fix: warehouse router tracker

[achettyiitr]

Description

• In the previous implementation, we are sending the warehouse_track_upload_missing Guage metrics twice. First with value 0 and then if missing upload exists we send value with 1.
• The way alerts works is, if the value 1 is continuously fired for 2H then the alert is being sent. But if the value comes as 0 it will get resolved. For calculating the value it uses whatever it being present at that instant.

Linear Ticket

• Resolves WAR-114

Security

• The code changed/added as part of this pull request won't create any security issues with how the software is being used.

[codecov]

Codecov Report

Attention: Patch coverage is 93.49593% with 8 lines in your changes missing coverage. Please review.

Project coverage is 74.73%. Comparing base (29b279d) to head (b436b44).
Report is 2 commits behind head on release/1.40.x.

Files with missing lines	Patch %	Lines
warehouse/router/tracker.go	93.00%	6 Missing and 1 partial ⚠️
warehouse/router/identities.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##           release/1.40.x    #5407      +/-   ##
==================================================
- Coverage           74.80%   74.73%   -0.07%     
==================================================
  Files                 440      440              
  Lines               61442    61412      -30     
==================================================
- Hits                45963    45899      -64     
- Misses              12950    12972      +22     
- Partials             2529     2541      +12     

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[RanjeetMishra]

Was just checking indexes for uploads table.

1. Do we keep deleting old entries from UploadsTable else without proper index on time columns this query can keep getting slower with time.
2. Not relevant to this PR. CREATE INDEX wh_uploads_status_index ON wh_uploads(status text_ops); index on status column with very low cardinality could have more performance drawbacks.

[achettyiitr]

Do we keep deleting old entries from UploadsTable else without proper index on time columns this query can keep getting slower with time.

Yes.

rudder-server/warehouse/archive/archiver.go

Line 510 in b51605a

func (a *Archiver) Delete(ctx context.Context) error {

[achettyiitr]

Not relevant to this PR. CREATE INDEX wh_uploads_status_index ON wh_uploads(status text_ops); index on status column with very low cardinality could have more performance drawbacks.

True, For columns with low cardinality, PostgreSQL might opt for a sequential scan over using the index, as scanning the table can be more efficient than traversing an index with low selectivity.

[achettyiitr]

Tracking Query-related optimizations/discussions in this doc.