Reduce DefaultObservabilitySymbolCollector object memory

[NipunaMadhushan]

Purpose

Fix OOM issue occurred in choreo-cp-graphql.

Fixes https://github.com/wso2-enterprise/internal-support-ballerina/issues/273

Approach

When observability is enabled, DefaultObservabilitySymbolCollector static object is created which has a memory of ~400MB in the issue mentioned above. It contains all metadata of modules and their documents in the package including syntax trees of each document. It has only been used in Generating Executable stage in compilation to create <module-name>-observability-symbols.jar which contains syntax-tree.json. To create syntax-tree.json, a syntax tree data string has been created which also contains a memory of ~180MB.

In this approach, instead of storing metadata of all modules and documents, those data has been used directly to create syntax tree data string and it has been stored in the PackageHolder where the module data has been stored previously. This method reduces the memory of DefaultObservabilitySymbolCollector static object from ~400MB to ~180MB and additionally syntax tree data string is not needed to be created at the Generating Executable stage.

Samples

Provide high-level details about the samples related to this feature.

Remarks

List any other known issues, related PRs, TODO items, or any other notes related to the PR.

Check List

• Read the Contributing Guide
• Updated Change Log
• Checked Tooling Support (#)
• Added necessary tests
  • Unit Tests
  • Spec Conformance Tests
  • Integration Tests
  • Ballerina By Example Tests
• Increased Test Coverage
• Added necessary documentation
  • API documentation
  • Module documentation in Module.md files
  • Ballerina By Examples

[gabilang]

Shall we remove the ModuleHolder and DocumentHolder classes?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (1b14109) 80.79% compared to head (759c0cf) 76.82%.
Report is 1259 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #41078      +/-   ##
============================================
- Coverage     80.79%   76.82%   -3.97%     
+ Complexity    77993    53465   -24528     
============================================
  Files          3414     2881     -533     
  Lines        275030   201542   -73488     
  Branches      49786    26654   -23132     
============================================
- Hits         222210   154837   -67373     
+ Misses        43793    38247    -5546     
+ Partials       9027     8458     -569     

see 1228 files with indirect coverage changes

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[github-actions]

This PR has been open for more than 15 days with no activity. This will be closed in 3 days unless the stale label is removed or commented.

[github-actions]

This PR has been open for more than 15 days with no activity. This will be closed in 3 days unless the stale label is removed or commented.

[NipunaMadhushan]

Shall we remove the ModuleHolder and DocumentHolder classes?

Addressed the suggestions

[github-actions]

This PR has been open for more than 15 days with no activity. This will be closed in 3 days unless the stale label is removed or commented.

[github-actions]

Closed PR due to inactivity for more than 18 days.

[gabilang]

LGTM