> [!NOTE] Sample Scan
> <table>
> <tr>
> <td width="25%"><img src="assets/ex_samplescan.png"></td>
> <td>Implements the <code>TABLESAMPLE</code> clause. Instead of scanning the whole table, the engine uses a specific sampling method (Bernoulli or System) to select a random subset of pages or rows, drastically reducing I/O for statistical queries.</td>
> </tr>
> </table>
>
> ```sql
> -- Sampling 10% of the animals table using the SYSTEM method
> EXPLAIN (ANALYZE, COSTS, BUFFERS, VERBOSE)
> SELECT * FROM animals TABLESAMPLE SYSTEM (10);
> ```
>
> 
>
> ```text
> Sample Scan on public.animals (cost=0.00..38.00 rows=1000 width=27) (actual time=0.003..0.013 rows=272 loops=1)
> Output: id, name, species_id, created_at
> Sampling: system ('10'::real)
> Buffers: shared hit=2
> Planning:
> Buffers: shared hit=73
> Planning Time: 0.163 ms
> Execution Time: 0.025 ms
> ```
>
> 
>
> <table>
> <tr>
> <td rowspan="2" width="25%"><img src="assets/ex_scan.svg"></td>
> <td><b>Performance</b></td><td>High performance; <code>SYSTEM</code> sampling is typically much faster than <code>BERNOULLI</code> as it samples at the block level rather than the row level.</td>
> </tr>
> <tr><td><b>Cost</b></td><td><code>sampling cost * sample size</code></td></tr>
> </table>