# MARS-835-PREHOOK: Parallel Processing for DATA_EXPORTER

## Overview
Implements parallel partition processing for DATA_EXPORTER package using **DBMS_PARALLEL_EXECUTE** framework.

## Changes Summary

### ENV_MANAGER v3.1.0 → v3.2.0
- Added `CODE_INVALID_PARALLEL_DEGREE` (-20110) error code
- Added `CODE_PARALLEL_EXECUTION_FAILED` (-20111) error code
- Added corresponding message constants and exception declarations

### DATA_EXPORTER v2.2.0 → v2.3.0
- Added `pParallelDegree` parameter to `EXPORT_TABLE_DATA_BY_DATE` (default: 1, range: 1-16)
- Added `pParallelDegree` parameter to `EXPORT_TABLE_DATA_TO_CSV_BY_DATE` (default: 1, range: 1-16)
- Implemented `EXPORT_PARTITION_PARALLEL` callback procedure for DBMS_PARALLEL_EXECUTE
- Created global temporary table `A_PARALLEL_EXPORT_CHUNKS` for chunk management
- Sequential processing when `pParallelDegree = 1` (default - safest option)
- Parallel processing via DBMS_PARALLEL_EXECUTE when `pParallelDegree > 1`
- Automatic error detection and reporting through `USER_PARALLEL_EXECUTE_CHUNKS`

## Installation

### Prerequisites
- Oracle Database 23ai or higher (DBMS_PARALLEL_EXECUTE support)
- ADMIN privileges for table creation
- CT_MRDS schema for package deployment

### Installation Command
```powershell
cd .\MARS_Packages\REL01_POST_DEACTIVATION\MARS-835-PREHOOK
echo "YES" | sql "ADMIN/Cloudpass#34@ggmichalski_high" "@install_mars835_prehook.sql"
```

## Usage Examples

### Parallel Export (8 threads)
```sql
BEGIN
    CT_MRDS.DATA_EXPORTER.EXPORT_TABLE_DATA_BY_DATE(
        pSchemaName     => 'OU_TOP',
        pTableName      => 'AGGREGATED_ALLOTMENT',
        pKeyColumnName  => 'A_WORKFLOW_HISTORY_KEY',
        pBucketArea     => 'ARCHIVE',
        pFolderName     => 'parallel_export',
        pMinDate        => DATE '2020-01-01',
        pMaxDate        => SYSDATE,
        pParallelDegree => 8
    );
END;
/
```

### Sequential Export
```sql
BEGIN
    CT_MRDS.DATA_EXPORTER.EXPORT_TABLE_DATA_BY_DATE(
        pSchemaName     => 'OU_TOP',
        pTableName      => 'AGGREGATED_ALLOTMENT',
        pKeyColumnName  => 'A_WORKFLOW_HISTORY_KEY',
        pBucketArea     => 'DATA',
        pFolderName     => 'sequential_export',
        pParallelDegree => 1  -- Sequential
    );
END;
/
```

## Test Results
✅ Installation successful
✅ ENV_MANAGER v3.2.0 compiled
✅ DATA_EXPORTER v2.3.0 compiled  
✅ Zero partition handling works correctly
✅ DBMS_PARALLEL_EXECUTE framework verified

## Rollback
```powershell
sql "ADMIN/Cloudpass#34@ggmichalski_high" "@rollback_mars835_prehook.sql"
```

## Author
Grzegorz Michalski - 2025-12-20