> ## Documentation Index
> Fetch the complete documentation index at: https://docs.btsscorp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Executing Queries

> Execute SQL with per-tab isolation, background execution, and instant cancellation in Koala Data Explorer.

## Overview

Koala Data Explorer provides multiple ways to execute SQL queries against your Oracle Fusion Cloud data. This guide covers query execution methods, options, and best practices.

## Execution Methods

### Quick Execute

The fastest way to run queries:

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"

### Execute Selection

Run only selected SQL:

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

<Tip>
  This is useful when you have multiple queries in one editor and want to run them individually.
</Tip>

### Execute Current Statement

Automatically detect and run the statement at cursor position:

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

## Query Execution Options

### Execution Settings

Configure how queries are executed:

```json theme={null}
{
  "koala.execution.timeout": 30000,
  "koala.execution.fetchSize": 100,
  "koala.execution.maxRows": 1000,
  "koala.execution.stopOnError": true
}
```

### Row Limits

Control how many rows are returned:

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

Set custom limits:

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

### Timeout Configuration

Prevent long-running queries:

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

To set query-specific timeout:

```sql theme={null}
-- @timeout: 60000
SELECT * FROM large_table;
```

## Multi-Statement Execution

### Sequential Execution (Paid)

Execute multiple statements in order:

```sql theme={null}
-- Statement 1
SELECT COUNT(*) FROM employees;

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

-- Statement 3
SELECT * FROM departments;
```

Press `Ctrl+Shift+Enter` to run all statements sequentially.

### Multi-Statement Execution

When executing multiple statements:

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

## Query Parameters

### Bind Variables

Use bind variables for dynamic queries:

```sql theme={null}
SELECT * FROM employees 
WHERE department_id = :dept_id
AND hire_date > :start_date;
```

When executed, Koala will prompt for parameter values in an input dialog.

## Execution Status

### Progress Indicators

Monitor query execution:

* **Spinner**: Query is running
* **Progress Bar**: Shows fetch progress for large results
* **Timer**: Displays elapsed time
* **Cancel Button**: Stops the active tab's query without affecting others

### Status Messages

Execution feedback appears in:

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

## Cancel Query Execution

### How to Cancel

Stop a running query:

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

### What Happens on Cancel

* Query execution stops on the server for the active tab only
* Partial results may be returned
* Connection remains active
* Transaction is rolled back (if applicable)
* Other tabs continue running their own queries

<Warning>
  Some queries may continue running on the Oracle server even after cancellation. Check with your DBA if concerned about long-running queries.
</Warning>

## Tab isolation and background execution

* Each tab has an isolated execution context; cancelling one tab does not interrupt others.
* You can switch tabs while a query runs in the background; status and cancel remain available from the originating tab.
* Switching connections within a tab will cancel any in-flight query for that tab.

## Execution History

### View Recent Queries

Access query history:

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

### History Features

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

Each history entry includes:

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

## Performance Optimization

### 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

### Query Performance

Monitor query performance:

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

## Error Handling

### Common Execution Errors

#### ORA-00942: Table or view does not exist

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

#### ORA-00936: Missing expression

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

#### ORA-01017: Invalid username/password

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

### Error Display

Errors appear in:

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

## Export Results

After query execution, you can 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

## Best Practices

### Before Execution

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

### During Execution

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

### After Execution

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

## Keyboard Shortcuts

| Action            | Windows/Linux      | Mac               |
| ----------------- | ------------------ | ----------------- |
| Execute Query     | `Ctrl+Enter`       | `Cmd+Enter`       |
| Execute Selection | `Ctrl+Shift+Enter` | `Cmd+Shift+Enter` |
| Cancel Execution  | `Ctrl+Alt+C`       | `Cmd+Option+C`    |
| Query History     | `Ctrl+H`           | `Cmd+H`           |

## Next Steps

<CardGroup cols={2}>
  <Card title="Keyboard Shortcuts" icon="keyboard" href="/koala/editor/keyboard-shortcuts">
    Master all keyboard shortcuts
  </Card>

  <Card title="Viewing Results" icon="table" href="/koala/results/viewing-data">
    Work with query results
  </Card>
</CardGroup>