To prove the performance increase, it would be worth running tests before and after the changes. For example, on 100,000 or more records.

The second point: Now it is impossible to change the value of the config at runtime if the connection object is the same. You need to specify this in the documentation.

The third. The Feature config was previously replaced and its settings were transferred to the main code. Perhaps it can already be adapted by transferring it to the Database?

Edit: Rebase develop branch before PR

To prove the performance increase, it would be worth running tests before and after the changes. For example, on 100,000 or more records.

The second point: Now it is impossible to change the value of the config at runtime if the connection object is the same. You need to specify this in the documentation.

The third. The Feature config was previously replaced and its settings were transferred to the main code. Perhaps it can already be adapted by transferring it to the Database?

Edit: Rebase develop branch before PR

The complexity improvement is self-evident (reducing multiple config lookups per query build down to O(1)). Additionally, benchmarking with 100k+ records wouldn't be relevant here, as this optimization strictly affects the PHP-side query compilation time, not the database execution or fetching speed.

The config has a cache. In some cases, I think this will have little effect on performance. The second point is important, because initially it was possible to change the configuration, but now it is impossible.

php benchmark_limit.php
--- BENCHMARK: BaseBuilder limit() ---
Current Branch: develop
Iterations: 500,000

[1] Time taken for 500000 calls to limit(0): 1.0128 seconds
gr8man@hp255r:~/Publiczny/codeigniter/CodeIgniter4$ php benchmark_limit.php
--- BENCHMARK: BaseBuilder limit() ---
Current Branch: perf/optimize-limitZeroAsAll
Iterations: 500,000

[1] Time taken for 500000 calls to limit(0): 0.2106 seconds

`<?php

require DIR . '/vendor/autoload.php';
require DIR . '/system/Test/bootstrap.php';

use CodeIgniter\Database\BaseBuilder;
use CodeIgniter\Test\Mock\MockConnection;

$count = 500000;

$db = new MockConnection([]);

echo "--- BENCHMARK: BaseBuilder limit() ---\n";
echo "Current Branch: " . trim(shell_exec('git rev-parse --abbrev-ref HEAD')) . "\n";
echo "Iterations: " . number_format($count) . "\n\n";

$start = microtime(true);

$builder = new BaseBuilder('my_table', $db);
for ($i = 0; $i < $count; $i++) {
$builder->limit(0);
}

$end = microtime(true);
$time = $end - $start;

echo "[1] Time taken for {$count} calls to limit(0): " . number_format($time, 4) . " seconds\n";
`