Database error warning during update to 9.9.3

Hi @oxfordmetadata,

I understand you’re seeing a series of database errors during the update to WooCommerce 9.9.3, particularly around duplicate or conflicting keys during the dbDelta execution. That’s definitely concerning when you’re just trying to run a smooth update.

The errors you shared suggest that the update script is trying to add primary or secondary keys to tables where those already exist, which usually means the database schema has diverged slightly from what WooCommerce expects. This can happen with older installs, manual database edits, or previously interrupted updates.

To move forward safely, here’s what I’d recommend:

1. Backup your database if you haven’t already.
2. Check for duplicate indexes manually in your database for tables like:
   • wp_woocommerce_order_itemmeta
   • wp_wc_order_operational_data
   • wp_wc_orders_meta
   You can use a tool like phpMyAdmin or a DB client to look at existing indexes. If meta_key, order_key, or meta_key_value indexes already exist, WooCommerce is trying to add them again — which causes the error.
3. Do not manually delete these indexes unless you’re certain they’re not being used. Instead, we recommend using the built-in WooCommerce database tools:
   • Go to WooCommerce > Status > Tools
   • Run “Update WooCommerce Database”
   • You can also try the “Verify database schema” tool if available
4. If the issue persists, you can temporarily enable debugging in wp-config.php to capture any additional detail during the update:

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', false );

Once done, check the log in /wp-content/debug.log.

If you’re still seeing errors or unsure about the index state, feel free to share the result of SHOW INDEX FROM wp_woocommerce_order_itemmeta; and similar queries, and I can help interpret it.

Let me know how it goes!

Hi @oxfordmetadata,

Thank you for the update. I’m really glad you were able to trace the issue back to the indexes created by the Index MySQL plugin. That makes perfect sense, and it’s great to hear that you’re excited about the performance-focused improvements now being incorporated directly into WooCommerce core.

If everything is running smoothly now and the update completed without further issues, then you’re all set. If you run into anything else during your next update or with database optimization, feel free to reach out anytime.

If WooCommerce has been useful for your store and you appreciate the support you’ve received, we’d truly appreciate it if you could leave us a quick review here: https://ww.wp.xz.cn/support/plugin/woocommerce/reviews/#new-post

Wishing you smooth updates ahead!

Hi @oxfordmetadata and @joy0114,

Thank you both for continuing the discussion and sharing your insights — it’s always great to see community members helping each other out! This kind of collaboration makes a real difference, especially with more technical upgrade-related issues like this one.

If you run into any other issue or need further help down the road, feel free to open a new topic here in the forum. We’re always happy to help where we can.

And if WooCommerce has been useful for your store and you appreciate the support and community you’ve found here, we’d truly appreciate it if you could leave us a quick review: https://ww.wp.xz.cn/support/plugin/woocommerce/reviews/#new-post

Wishing you both a smooth and optimized WooCommerce experience ahead!