Admin Query Profiler for WooCommerce

Finds out which plugin is making your WooCommerce admin slow, by attributing every database query to the plugin that caused it.

Your orders screen takes forever. You've migrated to High-Performance Order Storage, cleaned the database, and it's still slow. The usual next step is to deactivate plugins one at a time until it speeds up. This tells you which one to deactivate.

Install

Download this repository as a ZIP and upload it via Plugins → Add New → Upload Plugin, or clone it into wp-content/plugins/.

No configuration. Nothing runs until you ask it to.

Use

1. Open a slow admin screen — usually WooCommerce → Orders.
2. Click Scan this screen in the admin bar.
3. Change the rows per page (Screen Options, top right) and scan again.
4. Read the verdict:

order-delivery-date-for-example runs about 2.0 queries for every order shown. At 100 rows that is roughly 205 queries from this one plugin.

Why it makes you scan twice

A single page load genuinely cannot tell a per-row cost from a fixed one. A plugin firing a constant 19 queries looks like this:

Nothing changed but the denominator. So the first scan reports counts only, and the second compares against it:

queries(n) = fixed + slope × n

Only slope is an N+1. Showing a verdict after one scan would mean guessing, and in testing that guess accused an innocent plugin.

Why not just use Query Monitor?

Query Monitor is an excellent tool and this is not a replacement for it. But its Component column tells you which code ran a query, not which code caused it.

That matters more than it sounds. When a third-party plugin calls wc_get_order() inside an orders-list column, the query is issued by WooCommerce's own data store — so naive attribution blames WooCommerce and lets the real culprit off entirely:

Two of those three came from a third-party column callback. This plugin blames the innermost frame a WordPress hook invoked — the last point where control passed from WordPress into plugin code — which finds the initiator instead.

… → ListTable->column_default        [woocommerce]
    → do_action('manage_…_column')   [dispatcher]
      → WP_Hook->apply_filters       [dispatcher]
        → SomePlugin->render_column  [the plugin]   ← blame this
          → wc_get_order             [woocommerce]
            → OrdersTableDataStore->read [woocommerce]
              → wpdb->get_results    [core]

Query Monitor is explicitly excluded from attribution — its database dropin wraps every query, so without that exclusion it would be blamed for all of them. The two run together fine.

Query timings

Counts and attribution work with no configuration. Per-query timings additionally require SAVEQUERIES:

define( 'SAVEQUERIES', true );

That roughly doubles the memory a page load uses — turn it on to investigate, off again afterwards. N+1 detection doesn't need it.

SAVEQUERIES can't be enabled by a plugin: wpdb tests the constant at query time, so it must be set before WordPress boots. Query Monitor works around that with a db.php dropin, but WordPress permits exactly one db.php, so doing the same would make this incompatible with Query Monitor. Instead, without SAVEQUERIES this hooks core's query filter, which yields counts and backtraces but no timing.

Safety

• Profiles only the single request where you press the button.
• Requires manage_woocommerce or manage_options, plus a valid nonce.
• Never runs for logged-out visitors.
• Captured queries are capped at 8,000 so the profiler can't exhaust memory.
• Changes nothing, fixes nothing, and contacts no external service.

Profiling a request does make that request slower and use more memory. Don't leave scans running in a loop on a busy store.

Status

Early — version 0.1.0. Validated against a synthetic 500,000-order store (WooCommerce 11, HPOS, MySQL 8, 10 popular plugins), where it correctly identified a plugin costing 2 queries per row; deactivating only that plugin removed exactly the predicted 205 queries and cut the screen from 0.62s to 0.47s.

Reports from real stores are very welcome — especially anything where the verdict looks wrong.

License

GPL-2.0-or-later