“Variation as product” causes memory exhausted crash
- This topic has 10 replies, 2 voices, and was last updated 2 months, 2 weeks ago by
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Posts
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Environment:
- Woodmart 8.4 (latest)
- WordPress + WooCommerce + Elementor Pro (latest)
- Hosting: Kinsta (WP_MEMORY_LIMIT: 256MB, PHP memory_limit: unlimited)
- Catalog: ~20 products, ~10 variations total
The problem:
<p>
When “Show single variation” = YES and “Hide variations parent” = YES, the site crashes with:
</p>PHP Fatal error: Allowed memory size exhausted in class-wpdb.php line 2357<p>
This happens when applying multiple layered navigation filters on shop/category pages.
</p>- Crash occurs with 3–4 filters on main categories
- Crash occurs with only 2 filters on subcategories
<p>
This happens even with 512MB WP_MEMORY_LIMIT and when the query returns only 1–2 products.
</p><p>
Database is very small:
</p>- 783 posts
- 6128 postmeta
- 1132 term_relationships
<p>
We tested on another Woodmart site (50x more products, same stack, “Variation as product” OFF) → no issue at all.
</p><p>
Disabling “Variation as product” immediately resolves the problem.
</p>How to reproduce:
- Enable:
- “Show single variation” = YES
- “Hide variations parent” = YES
- Go to a category page
- Apply multiple filters (example: color + extensible + wheels + fabrication, with query_type=or)
- Result → Fatal error (memory exhausted)
<p>
On subcategories (e.g. /samsonite/upscape/), the crash occurs with only 2 filters.
</p>Root cause (confirmed via SSH debugging):
- Each filter adds a LEFT JOIN on
wp_term_relationships - Multiple filters = multiple JOINs on the same table
- The module
show-single-variations/class-query.phpadds ~5 subqueries per request:- Dependent subquery on wp_posts
- Multiple NOT IN (wp_postmeta)
- NOT IN (wp_term_relationships)
- Additional UNION on lookup table
Result → very complex SQL query despite tiny dataset
mysqli_query always tries to allocate ~14.5MB regardless of result count
PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 14596719 bytes) in class-wpdb.php on line 2357
- EXPLAIN shows only ~26 rows scanned
- The query returns only 1–2 products
- The issue is not data volume, but query structure
What we need from you:
- Is this a known issue with “Variation as product”?
- Is there a fix or patch available?
- If not, is there a way to disable this logic only on filtered pages (URL containing ?filter_)?
Temporary workarounds:
- WP_MEMORY_LIMIT increased (40M → 256M)
- Bots blocked on filter URLs (robots.txt + mu-plugin returning 503)
- Filters set to OR only (AND makes it worse)
<p>
Current state:
</p>- Stable with 1–3 filters
- Crash at 4 filters (or 2 on subcategories)
<p>Thank you</p>
We were able to replicate the issue with all non-theme-related plugins deactivated. The only exception is WPCode Lite, which we can’t deactivate without impacting the user experience. Of course, we kept Elementor/Elementor Pro active since they’re supposed to work with Woodmart
