Storing Outputs

Storing Outputs#

This documentation describes the functionality of the output processing system used to store simulation outputs either in a database or as CSV files. It covers the configuration, data buffering, conversion, and storage mechanisms of the main class as well as the support class for database maintenance.

WriteOutput Class#

The WriteOutput class is responsible for:

  • Collecting simulation output messages.

  • Buffering data until either a time-based interval or a memory limit is reached.

  • Converting raw data into structured pandas DataFrames.

  • Storing data into a database and/or exporting it as CSV files.

  • Managing performance trade-offs by allowing configuration of buffer sizes and storage intervals.

This class is part of the assume.common.outputs module. For more details, refer to assume.common.outputs.WriteOutput.

Data Processing Workflow#

  1. Message Handling:

    • The method handle_output_message receives asynchronous messages containing simulation outputs.

    • Data is buffered in lists corresponding to the intended database tables based on content type.

  2. Buffer Size Management:

    • The memory usage of buffered data is monitored continuously.

    • If memory usage exceeds the outputs_buffer_size_mb threshold, buffered data is flushed to storage.

  3. Data Conversion:

    • Helper methods like convert_rl_params and convert_market_results transform raw data into DataFrames suitable for storage.

  4. Data Storage:

    • The method store_dfs flushes buffered DataFrames to storage based on time intervals (save_frequency_hours) or buffer size limits.

Performance Considerations#

  • Buffering Strategy: Increasing outputs_buffer_size_mb can improve performance by reducing write frequency. Default: 300 MB.

  • Write Intervals: Setting save_frequency_hours facilitates real-time observation with Grafana dashboards. Disabling this by setting it to null improves performance but prevents real-time monitoring.

  • Optimal Configuration: Increase outputs_buffer_size_mb and disable save_frequency_hours for maximum performance. Ensure sufficient memory is available.

Note

When storing results as CSV files, save_frequency is automatically disabled, meaning data is only saved at the end of the simulation or if the buffer size limit is reached. This prevents real-time observation through Grafana dashboards.

Database Tables Overview#

The simulation outputs are stored in various tables. Below is a breakdown of tables, their purpose, and what columns they contain. When the outputs are stored in CSV files, the data is organized in a similar structure, with each table represented as a separate CSV file.

Table Name

Purpose

Columns

market_meta

Market-related data.

simulation, market_id, time, node, product_start, product_end, only_hours, price, max_price, min_price, supply_volume, supply_volume_energy, demand_volume, demand_volume_energy

market_dispatch

Dispatch data for markets.

simulation, market_id, datetime, unit_id, power

unit_dispatch

Unit-level dispatch data.

simulation, unit, power, heat, soc, energy_generation_costs, energy_cashflow, total_costs

market_orders

Market order details.

simulation, market_id, node, bid_id, unit_id, parent_bid_id, bid_type, end_time, price, volume, accepted_price, accepted_volume, min_acceptance_ratio

power_plant_meta

Power plant metadata.

simulation, unit_id, unit_type (“power_plant”), max_power, min_power, emission_factor, efficiency

storage_meta

Storage unit metadata.

simulation, unit_id, unit_type (“storage”), capacity, max_soc, min_soc, max_power_charge, max_power_discharge, min_power_charge, min_power_discharge, efficiency_charge, efficiency_discharge

rl_params

Reinforcement learning parameters.

simulation, unit, datetime, evaluation_mode, episode, profit, reward, regret, actions, exploration_noise, critic_loss, total_grad_norm, max_grad_norm, learning_rate

rl_meta

Reinforcement learning metadata.

simulation, episode, eval_episode, learning_mode, evaluation_mode

Note

The columns for all unit_meta like power_plant_meta and storage_meta are not listed here. Their structure is dictated by the as_dict method in the respective unit classes.

DatabaseMaintenance Class#

The DatabaseMaintenance class provides utility functions for managing simulation data stored in a database. It includes:

  • Retrieving unique simulation IDs from the database.

  • Deleting specific simulations.

  • Performing bulk deletion of simulation data with optional exclusions.

This class is part of the assume.common.outputs module. For more details, refer to assume.common.outputs.DatabaseMaintenance.

Usage Example#

Below is an example YAML configuration snippet for a simulation configuring the save frequency and buffer size:

example_simulation:
  simulation_id: example_simulation
  start: 2025-01-01 00:00:00
  end: 2025-01-02 00:00:00
  save_frequency_hours: 24 # Time interval for saving data in hours
  outputs_buffer_size_mb: 300  # Buffer size in MB

Example usage of the DatabaseMaintenance class:

from assume.common import DatabaseMaintenance

# Select to store the simulation results in a local database or in TimescaleDB.
# When using TimescaleDB, ensure Docker is installed and the Grafana dashboard is accessible.
data_format = "timescale"  # Options: "local_db" or "timescale"

if data_format == "local_db":
    db_uri = "sqlite:///./examples/local_db/assume_db.db"
elif data_format == "timescale":
    db_uri = "postgresql://assume:assume@localhost:5432/assume"

maintenance = DatabaseMaintenance(db_uri=db_uri)

# 1. Retrieve unique simulation IDs:
unique_ids = maintenance.get_unique_simulation_ids()
print("Unique simulation IDs:", unique_ids)

# 2. Delete specific simulations:
maintenance.delete_simulations(["example_01", "example_02"])

# 3. Delete all simulations except a few:
maintenance.delete_all_simulations(exclude=["example_01"])
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