Cache Issues Troubleshooting

Cache Not Storing Translations

Symptoms

1. Every page load triggers new API call
2. High API costs despite cache enabled
3. Translation takes same time on repeat visits
4. Cache statistics show 0% hit rate

Diagnosis Steps


1. Verify Cache is Enabled:
`
ShahiTranslate Pro → Settings → General → Cache Settings
Ensure “Enable Translation Cache” is checked
`

2. Check Database Tables:
`sql
— Run in phpMyAdmin
SHOW TABLES LIKE ‘wpstptranslations’;
SELECT COUNT(*) FROM wpstptranslations;
`
Should show the table exists and has rows

3. Check Error Logs:
`
Tools → Site Health → Info → Server → Error Log
Look for database permission errors
`

4. Test Cache Write:
`

5. Clear all cache
6. Visit a page in Spanish
7. Check database: should see new rows in wpstptranslations
8. Revisit same page: should load faster

`

Solutions


Database Permission Issues:

9. User needs INSERT, UPDATE, SELECT privileges
10. Contact hosting provider to verify
11. Or manually grant:

`sql
GRANT INSERT, UPDATE, SELECT ON databasename.wpstp_translations TO ‘user’@’localhost’;
`

Table Corruption:
`sql
— Run in phpMyAdmin
REPAIR TABLE wpstptranslations;
OPTIMIZE TABLE wpstptranslations;
`

Insufficient Disk Space:

12. Check hosting disk quota
13. Clean up old backups and files
14. Upgrade hosting plan if needed

Cache Plugin Conflict:

15. Some caching plugins interfere with database writes
16. Try temporarily disabling caching plugin
17. If fixed, configure caching plugin to exclude:

– Table: wpstptranslations
– Database writes from caching

Object Cache Misconfiguration:

18. If using Redis/Memcached, verify it’s working:

`php
// Add to test file
vardump(wpusingextobject_cache());
// Should return true if object cache active
`

19. Reinstall object cache plugin if false

Cache Serving Stale Content


Symptoms


20. Updated content still shows old translation
21. Content edited but translation unchanged
22. New content shows old translations

Causes


23. Cache not invalidating on content update
24. Very long cache duration
25. External caching layers not clearing

Solutions


Immediate Fix – Manual Clear:
`
ShahiTranslate Pro → Settings → General → Clear Cache
Select “Clear Specific Content” → Choose the affected page
`

Enable Auto-Invalidation:
`
Settings → Advanced → Cache → Auto-Invalidation
✅ Clear cache when content updated
✅ Clear cache when translation edited
✅ Clear cache on settings change
`

Reduce Cache Duration (if updates frequent):
`
Settings → General → Cache Duration
Change from 90 days to 7 days for frequently updated content
`

Configure Caching Plugin:

For WP Rocket:
`
WP Rocket → Advanced → Never cache these cookies:
Add: stplanguage, stpcache_bypass
`

For W3 Total Cache:
`
Performance → Page Cache → Never cache these pages:
Add: .lang=[^&]
`

Clear CDN Cache:

26. Cloudflare: Purge Everything or Purge by URL
27. Other CDNs: Check their documentation
28. Set up webhook for automatic CDN purge on content update

Verify Cache Keys:
`
Settings → Advanced → Cache → Cache Key Components
✅ URL
✅ Language
✅ Post ID
✅ Last Modified Time (This is key!)
`

Cache Growing Too Large


Symptoms


29. Database size increasing rapidly
30. Slow database queries
31. “Disk quota exceeded” errors
32. Site slowdown over time

Check Current Size


Via phpMyAdmin:
`sql
SELECT
ROUND(SUM(datalength + indexlength) / 1024 / 1024, 2) AS “Size (MB)”
FROM information_schema.TABLES
WHERE tableschema = “yourdatabase_name”
AND tablename = “wpstp_translations”;
`

Via Plugin Dashboard:
`
ShahiTranslate Pro → Dashboard → Cache Statistics
Look at “Cache Size”
`

Solutions


Enable Auto-Cleanup:
`
Settings → Advanced → Cache → Cleanup Settings
✅ Enable automatic cleanup
Interval: Weekly
Keep translations from: Last 30 days
Max cache size: 500 MB
`

Manual Cleanup:
`
Settings → General → Clear Cache
Choose: “Clear cache older than X days”
Enter: 90 days
`

Remove Orphaned Translations:
`
ShahiTranslate Pro → Tools → Database Cleanup
✅ Remove translations for deleted content
✅ Remove duplicate entries
Click “Clean Database”
`

Optimize Tables:
`sql
— Run in phpMyAdmin monthly
OPTIMIZE TABLE wpstptranslations;
OPTIMIZE TABLE wpstpmanual_translations;
`

Reduce Cached Languages:
`
Settings → Languages
Deactivate languages you don’t actually need
Each language multiplies cache size
`

Enable Compression:
`
Settings → Advanced → Cache → Compression
✅ Enable cache compression (reduces size by 40-60%)
`

Set Maximum Size:
`
Settings → Advanced → Cache
Max cache size: 1 GB (or appropriate limit)
When reached, oldest entries automatically deleted
`

Low Cache Hit Rate


What It Means


33. Cache hit rate = % of pages served from cache
34. Should be 90%+ for good performance
35. Low rate = frequent API calls, higher costs

Check Hit Rate


`
ShahiTranslate Pro → Dashboard → Cache Statistics
Cache Hit Rate: Should show 90%+
`

Causes and Solutions


Cause: Cache Not Warmed

Solution – Warm the Cache:
`
ShahiTranslate Pro → Tools → Cache Warming
Select: All published posts and pages
Languages: All active languages
Click: “Start Cache Warming”
`

Cause: Cache Duration Too Short

Solution:
`
Settings → General → Cache Duration
Increase from 7 days to 30 days
For static content: 90 days
`

Cause: Content Changing Frequently

Solution:
`
This is expected for dynamic content
Cache what you can:
✅ Static pages
✅ Old blog posts
⬜ Live feeds
⬜ Real-time data
`

Cause: Low Traffic

Solution:
`
Low traffic = fewer cache opportunities
Schedule cache warming for all content
Or wait as traffic increases
`

Cause: Many Languages, Small Audience per Language

Solution:
`
Focus on main languages
Deactivate rarely used languages
Use on-demand translation for others
`

Cause: Cache Being Cleared Too Frequently

Solution:
`
Settings → Advanced → Cache → Auto-Invalidation
Review what triggers cache clear
Disable aggressive clearing rules
`

Object Cache Issues


Redis Not Working


Check if Redis is Running:
`bash

SSH to server


redis-cli ping

Should respond: PONG


`

Check WordPress Connection:
`php
// Add temporary test page
dump(wpusingextobject_cache());
// Should be true
vardump(wpcacheget(‘testkey’));
wpcacheset(‘testkey’, ‘testvalue’, ”, 3600);
vardump(wpcacheget(‘testkey’));
// Should show ‘test_value’
?>
`

Solutions:

36. Install Redis Object Cache Plugin:

`
Plugins → Add New → Search “Redis Object Cache”
Install and activate
Settings → Redis → Enable Object Cache
`

37. Check Redis Configuration:

`php
// In wp-config.php
define(‘WPREDISHOST’, ‘127.0.0.1’);
define(‘WPREDISPORT’, 6379);
define(‘WPREDISPASSWORD’, ‘your-password’); // if set
define(‘WPREDISDATABASE’, 0);
`

38. Restart Redis:

`bash
sudo service redis-server restart
`

39. Check Redis Memory:

`bash
redis-cli info memory

Check used_memory vs maxmemory


`

Memcached Not Working


Check if Running:
`bash
echo “stats” | nc 127.0.0.1 11211
`

Install Memcached Plugin:
`

40. Install “Memcached Object Cache” plugin
41. Copy object-cache.php to wp-content/
42. Verify in Settings → Memcached

`

Common Issues:

43. Memcached not installed on server (contact host)
44. Wrong server address in configuration
45. Firewall blocking connection
46. Insufficient memory allocation

CDN Caching Issues


CDN Serving Wrong Language


Symptoms:

47. Spanish speakers see English
48. Language switches but content doesn’t
49. Random language appearing

Cause: CDN not aware of language variations

Solutions:

Cloudflare:
`

50. Go to Caching → Configuration
51. Cache Key: Custom
52. Add Query String: lang
53. Add Cookie: stp_language
54. Purge Everything

`

KeyCDN:
`
Zone → Advanced Settings
Cache Key: Enable
Include Query Parameters: yes
Add: lang parameter
`

Generic CDN:
`
Ensure cache key includes:

55. URL with language (example.com/es/)
56. Language cookie if using cookies
57. Accept-Language header if auto-detecting

`

CDN Not Caching at All


Check CDN Cache Status:
`
Browser DevTools → Network tab
Look for X-Cache header:

58. HIT = served from cache (good)
59. MISS = not cached
60. BYPASS = caching disabled for this request

`

Solutions:

61. Enable Caching for HTML:

`
Most CDNs don’t cache HTML by default
Enable in CDN settings
Set appropriate cache duration (1 hour – 1 day)
`

62. Remove Cache-Busting Headers:

`php
// Add to theme functions.php
addfilter(‘wpheaders’, function($headers) {
if (is_singular()) {
unset($headers[‘Cache-Control’]);
$headers[‘Cache-Control’] = ‘public, max-age=3600’;
}
return $headers;
});
`

63. Set Correct Cache Rules:

`
CDN should cache:

64. Pages with language parameter
65. Static assets (CSS, JS, images)
66. Flag images

CDN should NOT cache:

67. Admin pages
68. Login pages
69. Checkout/cart pages (if e-commerce)

`

Performance Still Slow


After Enabling Cache


Run Speed Test:
`
Tools: GTmetrix, Pingdom, Google PageSpeed Insights
Test both default and translated versions
`

Common Issues:

1. Database Queries Not Optimized:
`sql
— Add indexes if missing
ALTER TABLE wpstptranslations
ADD INDEX idxlookup (postid, language, cache_key);

ALTER TABLE wpstptranslations
ADD INDEX idxexpires (expiresat);
`

2. Too Many Translations per Page:
`
Settings → Advanced → Content Settings
Disable translation for:
⬜ Comments
⬜ Widgets (translate manually in widget settings)
⬜ Menus (translate once, save to cache)
`

3. Large Translation Strings:
`
Very long content takes time to retrieve
Consider splitting into smaller chunks
Or use lazy loading for below-fold content
`

4. Server Resources Insufficient:
`
Check server specs:

70. PHP memory: Should be 256MB+
71. MySQL connections: Sufficient for traffic
72. CPU: Not constantly at 100%

Consider upgrading hosting plan
`

5. No Object Cache:
`
THIS MAKES HUGE DIFFERENCE
Install Redis or Memcached
Can improve performance by 5-10x
Contact host to set up if not available
`

Prevention Tips


Best Practices


1. Set Up Monitoring:
`
Monitor:

73. Cache hit rate (weekly)
74. Database size (monthly)
75. API costs (daily if automatic translation)
76. Page load times (weekly)

Set alerts for anomalies
`

2. Regular Maintenance:
`
Monthly tasks:

77. Clear cache older than 90 days
78. Optimize database tables
79. Review error logs
80. Check disk space

Quarterly:

81. Review translation quality
82. Update outdated translations
83. Clean orphaned data

`

3. Proper Configuration:
`
✅ Cache enabled
✅ Object cache installed (Redis/Memcached)
✅ Appropriate cache duration
✅ Auto-cleanup enabled
✅ CDN configured correctly
✅ Monitoring in place
`

4. Test Before Production:
`
Test on staging site:

84. Cache functionality
85. Performance with cache
86. Cache clearing
87. Multi-language caching

Only deploy to production after thorough testing
`

Getting Help


If cache issues persist:

88. Gather Information:

– Cache statistics from dashboard
– Database table sizes
– Error log entries
– Server specifications

89. Run Diagnostic:

`
ShahiTranslate Pro → Tools → System Diagnostic
Download diagnostic report
`

90. Contact Support:

– Include diagnostic report
– Describe issue and steps taken
– Mention hosting provider
– Specify if using object cache/CDN

Next Steps


91. Performance Optimization
92. Common Issues
93. Translation Cache System