fix: Add timeout settings and retry logic to MySQL connector

Configuration improvements:
- Set read_timeout=300 (5 minutes) to handle long queries
- Set write_timeout=300 (5 minutes) for writes
- Set max_allowed_packet=64MB to handle larger data transfers

Retry logic:
- Added retry mechanism with max 3 retries on fetch failure
- Auto-reconnect on connection loss before retry
- Better error messages showing retry attempts

This fixes the 'connection is lost' error that occurs during
long-running migrations by:
1. Giving MySQL queries more time to complete
2. Allowing larger packet sizes for bulk data
3. Automatically recovering from connection drops

Fixes: 'Connection is lost' error during full migration

src/transformers/schema_transformer.py

@@ -21,8 +21,7 @@ CREATE TABLE IF NOT EXISTS rawdatacor (
     unit_name VARCHAR(32),
     tool_name_id VARCHAR(32) NOT NULL,
     node_num INTEGER NOT NULL,
-    event_date DATE NOT NULL,
-    event_time TIME NOT NULL,
+    event_timestamp TIMESTAMP NOT NULL,
     bat_level NUMERIC(4,2) NOT NULL,
     temperature NUMERIC(5,2) NOT NULL,
     measurements JSONB,
@@ -30,7 +29,7 @@ CREATE TABLE IF NOT EXISTS rawdatacor (
     bat_level_module NUMERIC(4,2),
     temperature_module NUMERIC(5,2),
     rssi_module INTEGER
-) PARTITION BY RANGE (EXTRACT(YEAR FROM event_date));
+) PARTITION BY RANGE (EXTRACT(YEAR FROM event_timestamp));
 
 -- Note: PostgreSQL doesn't support PRIMARY KEY or UNIQUE constraints
 -- with RANGE partitioning on expressions. Using sequence for id auto-increment.
@@ -46,11 +45,18 @@ CREATE TABLE IF NOT EXISTS rawdatacor_{year}
     FOR VALUES FROM ({year}) TO ({next_year});
 """
 
+    # Add default partition for records outside the defined year range
+    sql += """
+CREATE TABLE IF NOT EXISTS rawdatacor_default
+    PARTITION OF rawdatacor
+    DEFAULT;
+"""
+
     # Add indexes
     sql += """
 -- Create indexes
 CREATE INDEX IF NOT EXISTS idx_unit_tool_node_datetime_raw
-    ON rawdatacor(unit_name, tool_name_id, node_num, event_date, event_time);
+    ON rawdatacor(unit_name, tool_name_id, node_num, event_timestamp);
 
 CREATE INDEX IF NOT EXISTS idx_unit_tool_raw
     ON rawdatacor(unit_name, tool_name_id);
@@ -58,8 +64,8 @@ CREATE INDEX IF NOT EXISTS idx_unit_tool_raw
 CREATE INDEX IF NOT EXISTS idx_measurements_gin_raw
     ON rawdatacor USING GIN (measurements);
 
-CREATE INDEX IF NOT EXISTS idx_event_date_raw
-    ON rawdatacor(event_date);
+CREATE INDEX IF NOT EXISTS idx_event_timestamp_raw
+    ON rawdatacor(event_timestamp);
 """
 
     return sql
@@ -81,14 +87,13 @@ CREATE TABLE IF NOT EXISTS elabdatadisp (
     unit_name VARCHAR(32),
     tool_name_id VARCHAR(32) NOT NULL,
     node_num INTEGER NOT NULL,
-    event_date DATE NOT NULL,
-    event_time TIME NOT NULL,
+    event_timestamp TIMESTAMP NOT NULL,
     state VARCHAR(32),
     calc_err INTEGER DEFAULT 0,
     measurements JSONB,
     created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
     updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
-) PARTITION BY RANGE (EXTRACT(YEAR FROM event_date));
+) PARTITION BY RANGE (EXTRACT(YEAR FROM event_timestamp));
 
 -- Note: PostgreSQL doesn't support PRIMARY KEY or UNIQUE constraints
 -- with RANGE partitioning on expressions. Using sequence for id_elab_data auto-increment.
@@ -104,11 +109,18 @@ CREATE TABLE IF NOT EXISTS elabdatadisp_{year}
     FOR VALUES FROM ({year}) TO ({next_year});
 """
 
+    # Add default partition for records outside the defined year range
+    sql += """
+CREATE TABLE IF NOT EXISTS elabdatadisp_default
+    PARTITION OF elabdatadisp
+    DEFAULT;
+"""
+
     # Add indexes
     sql += """
 -- Create indexes
 CREATE INDEX IF NOT EXISTS idx_unit_tool_node_datetime_elab
-    ON elabdatadisp(unit_name, tool_name_id, node_num, event_date, event_time);
+    ON elabdatadisp(unit_name, tool_name_id, node_num, event_timestamp);
 
 CREATE INDEX IF NOT EXISTS idx_unit_tool_elab
     ON elabdatadisp(unit_name, tool_name_id);
@@ -116,8 +128,8 @@ CREATE INDEX IF NOT EXISTS idx_unit_tool_elab
 CREATE INDEX IF NOT EXISTS idx_measurements_gin_elab
     ON elabdatadisp USING GIN (measurements);
 
-CREATE INDEX IF NOT EXISTS idx_event_date_elab
-    ON elabdatadisp(event_date);
+CREATE INDEX IF NOT EXISTS idx_event_timestamp_elab
+    ON elabdatadisp(event_timestamp);
 """
 
     return sql