Executing Queries

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Overview

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Execution Methods

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Quick Execute

1. Keyboard Shortcut: Ctrl+Enter (Windows/Linux) or Cmd+Enter (Mac)
2. Button: Click the green “Run” button in the editor toolbar
3. Context Menu: Right-click → “Execute Query”

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Execute Selection

1. Select the SQL text you want to run
2. Press Ctrl+Shift+Enter or click “Run Selection”
3. Only the selected text will be executed

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Execute Current Statement

1. Place cursor anywhere in a SQL statement
2. Press Alt+Enter
3. Koala will identify statement boundaries and execute

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Query Execution Options

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Execution Settings

{
  "koala.execution.timeout": 30000,
  "koala.execution.fetchSize": 100,
  "koala.execution.maxRows": 1000,
  "koala.execution.stopOnError": true
}

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Row Limits

• Free Version: Maximum 50 rows per query
• Paid Version: Configurable, unlimited rows

1. Click the settings icon in query editor
2. Adjust “Max Rows” value
3. Use FETCH FIRST n ROWS ONLY in SQL for precise control

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Timeout Configuration

• Default timeout: 30 seconds
• Maximum timeout: 5 minutes
• Configure per-query or globally

-- @timeout: 60000
SELECT * FROM large_table;

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Multi-Statement Execution

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Sequential Execution (Paid)

-- Statement 1
SELECT COUNT(*) FROM employees;

-- Statement 2
SELECT department_id, COUNT(*) 
FROM employees 
GROUP BY department_id;

-- Statement 3
SELECT * FROM departments;

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Multi-Statement Execution

• Each statement executes sequentially
• Execution stops on first error
• Results shown for each completed statement

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Query Parameters

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Bind Variables

SELECT * FROM employees 
WHERE department_id = :dept_id
AND hire_date > :start_date;

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Execution Status

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Progress Indicators

• Spinner: Query is running
• Progress Bar: Shows fetch progress for large results
• Timer: Displays elapsed time
• Cancel Button: Stop long-running queries

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Status Messages

• Status bar (brief summary)
• Output panel (detailed logs)
• Results panel (row count, execution time)

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Cancel Query Execution

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How to Cancel

1. Click the “Cancel” button in the toolbar
2. Press Ctrl+Alt+C
3. Click “Stop” in the progress notification

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What Happens on Cancel

• Query execution stops on the server
• Partial results may be returned
• Connection remains active
• Transaction is rolled back (if applicable)

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Execution History

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View Recent Queries

1. Press Ctrl+H or click History icon
2. Browse executed queries
3. Click to reload any query
4. Filter by date, status, or connection

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History Features

• Free Version: Last 50 queries
• Paid Version: Last 500 queries with search

• SQL text
• Execution time
• Row count
• Timestamp
• Connection used

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Performance Optimization

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Query Performance Tips

1. Use Indexes: Include indexed columns in WHERE clauses
2. Limit Rows: Add FETCH FIRST or ROWNUM conditions
3. Select Specific Columns: Avoid SELECT *
4. Use Bind Variables: Improve query plan caching

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Query Performance

• Execution time displayed in results
• Row count shown
• Timeout warnings if query runs long

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Error Handling

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Common Execution Errors

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ORA-00942: Table or view does not exist

• Verify table name and schema
• Check user permissions
• Ensure correct connection

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ORA-00936: Missing expression

• Check SQL syntax
• Verify all columns exist
• Review JOIN conditions

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ORA-01017: Invalid username/password

• Re-authenticate connection
• Update stored credentials
• Check account status

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Error Display

• Inline: Red squiggly lines in editor
• Problems Panel: Detailed error list
• Output Panel: Full error stack trace

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Export Results

1. Click Export button in results toolbar
2. Choose format (CSV, JSON, or Excel for paid version)
3. Select save location
4. Results are saved to file

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Best Practices

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Before Execution

1. Review query for errors
2. Estimate result size
3. Consider adding row limits
4. Use explain plan for complex queries

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During Execution

1. Monitor progress for long queries
2. Be ready to cancel if needed
3. Watch for timeout warnings
4. Check connection stability

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After Execution

1. Verify result accuracy
2. Check execution time
3. Save useful queries
4. Export important results

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Keyboard Shortcuts

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Next Steps