[improve][io] The JDBC connector supports JSON substructure schema

[shibd]

Motivation

Currently, when JDBC to convert value that has substructure schema, will get error:

java.lang.Exception: Not supported value type, need to add it. class org.apache.pulsar.client.impl.schema.generic.GenericJsonRecord

I know handling substructure types is complex, and JDBC databases may not always support defining substructure types.

However, it is possible to write the substructure type as a JSON string into the table. This can be very useful for databases that support JSON parsing.

For examples:

1. JSON data

{
    "state": "ts",
    "zipCode": 1000,
    "pcList": [
        {
            "brand": "b1",
            "model": "m1"
        },
        {
            "brand": "b2",
            "model": "m2"
        }
    ]
}

2. We can insert it to table like:

state	zipCode	pcList
ts	1000	[{"brand":"b1","model":"m1"},{"brand":"b2","model":"m2"}]

Modifications

• When value instanceof GenericJsonRecord, use jsonNode string.

Verifying this change

• Add testSubFieldJsonArray to cover it.

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

Matching PR in forked repository

PR in forked repository:

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 73.43%. Comparing base (bbc6224) to head (f860ca8).
Report is 453 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #23043      +/-   ##
============================================
- Coverage     73.57%   73.43%   -0.15%     
- Complexity    32624    33101     +477     
============================================
  Files          1877     1914      +37     
  Lines        139502   143627    +4125     
  Branches      15299    15672     +373     
============================================
+ Hits         102638   105469    +2831     
- Misses        28908    30085    +1177     
- Partials       7956     8073     +117     

Flag	Coverage Δ
inttests	27.61% <0.00%> (+3.02%)	⬆️
systests	24.66% <0.00%> (+0.34%)	⬆️
unittests	72.50% <50.00%> (-0.35%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
.../apache/pulsar/io/jdbc/BaseJdbcAutoSchemaSink.java	74.48% <50.00%> (+1.62%)	⬆️

... and 500 files with indirect coverage changes