Translation Cache System

Overview

The translation cache system stores translated content for rapid retrieval, dramatically improving site performance and reducing API costs.

How Translation Caching Works

Basic Flow

1. Request: Visitor selects a language
2. Cache Check: System looks for cached translation
3. Cache Hit: If found, serve instantly (milliseconds)
4. Cache Miss: If not found, generate translation
5. Store: Save new translation to cache
6. Serve: Display to visitor

Cache Storage


Translations are stored in:

• Database: WordPress database tables (wpstptranslations)
• Object Cache: Redis/Memcached if available
• File Cache: Optional file-based caching
• CDN Cache: Compatible with CDN caching layers

Cache Configuration


Location: ShahiTranslate Pro → Settings → General → Cache Settings

Enable/Disable Caching


• Enable Translation Cache: ✅ On (recommended)

– Improves performance by 10-50x
– Reduces API costs by 90%+
– Essential for production sites

• Disable for Development: ⬜ Off

– Useful during testing
– See changes immediately
– Not recommended for live sites

Cache Duration


Default: 30 days

Settings:

• Short (7 days): For frequently updated content
• Medium (30 days): Standard, balanced approach
• Long (90 days): For static content, saves API costs
• Permanent: Never expire (manual clear only)
• Custom: Set specific duration in hours/days

Considerations:

• Longer = Better performance, lower costs
• Shorter = More up-to-date automatic translations
• Balance based on content update frequency

Cache Invalidation


Automatic Invalidation:

• When post/page is updated
• When manual translation is added/edited
• When source content changes
• When plugin settings change

Manual Invalidation:

• Clear all cache
• Clear specific language
• Clear specific post/page
• Clear by date range

Cache Types


Page Cache


What It Caches: Complete page translations

Benefits:

• Fastest possible loading
• Entire page served from cache
• No database queries needed

Limitations:

• More storage required
• May cache dynamic elements

Best For: Static pages, blog posts, product pages

Fragment Cache


What It Caches: Individual content pieces

Benefits:

• More flexible than page cache
• Allows dynamic elements
• Smaller storage footprint

Limitations:

• Slightly slower than page cache
• More complex to manage

Best For: Sites with dynamic content, personalization

Translation Memory Cache


What It Caches: Common phrases and segments

Benefits:

• Consistency across site
• Reduces redundant translations
• Speeds up new content translation

How It Works:

• Recognizes repeated phrases
• Reuses existing translations
• Builds over time

Example:

• “Add to Cart” appears on 100 product pages
• Translated once, reused 100 times
• Consistent translation everywhere

Cache Performance


Storage Optimization


Database Optimization:

• Indexed tables for fast lookups
• Automatic cleanup of old entries
• Compressed storage (reduces size by 40-60%)

Object Cache Integration:

• Redis support
• Memcached support
• APCu support
• Automatic detection and use

File Cache (Optional):

• Store translations as static files
• Served directly by web server
• Fastest possible delivery

Cache Statistics


Location: ShahiTranslate Pro → Dashboard → Cache Statistics

Metrics Displayed:

• Total Cached Items: Number of translations stored
• Cache Size: Storage space used
• Hit Rate: Percentage served from cache
• Miss Rate: Percentage requiring new translation
• API Calls Saved: Estimated cost savings
• Average Load Time: Performance improvement

Using Statistics:

• Monitor cache effectiveness
• Identify underperforming content
• Optimize cache settings
• Track cost savings

Cache Management


Clearing Cache


Location: ShahiTranslate Pro → Settings → General → Cache Settings → Clear Cache

Options:

• Clear All Cache

– Removes all cached translations
– Use when: Plugin updated, major changes made
– Impact: Temporary performance decrease

• Clear Specific Language

– Remove cache for one language only
– Use when: Language-specific issues
– Impact: Minimal, affects only that language

• Clear by Post Type

– Clear posts, pages, or custom post types
– Use when: Content structure changed
– Impact: Moderate, specific content type affected

• Clear by Date

– Remove cache older than X days
– Use when: Want to refresh old translations
– Impact: Varies based on date range

• Clear Single Item

– Remove cache for specific post/page
– Use when: Individual page updated
– Impact: Minimal, one item only

When to Clear Cache:

• After plugin updates
• When translations look wrong
• After theme changes
• When testing new configurations
• Periodically (e.g., monthly) for freshness

Automatic Cleanup


Auto-Cleanup Settings:

• Enable Auto-Cleanup: ✅ On
• Cleanup Interval: Daily, weekly, or custom
• Keep Last: Keep translations from last X days
• Max Size: Limit cache size (GB)

What Gets Cleaned:

• Translations older than retention period
• Orphaned translations (content deleted)
• Duplicate entries
• Corrupted cache entries

Cache Warming


What It Is: Pre-populate cache before visitors arrive

Benefits:

• No “first visitor” slowdown
• Consistent fast performance
• Better user experience

How to Use:

• Manual Warming:

– Go to ShahiTranslate Pro → Tools → Warm Cache
– Select language(s) to warm
– Choose content to translate
– Click “Start Cache Warming”

• Automatic Warming:

– Enable in settings
– Runs after content published
– Background processing (doesn’t slow site)

• Scheduled Warming:

– Set up cron job
– Warm cache at low-traffic times
– Ensure cache always full

Configuration:

• Pages to Warm: All, published, recent, or custom list
• Languages: Which languages to warm
• Schedule: Immediate, hourly, daily
• Batch Size: How many items per batch (prevents timeouts)

Cache and Performance


Page Load Times


Without Cache:

• Translation API call: 200-500ms
• Database queries: 50-100ms
• Total delay: 250-600ms per page

With Cache:

• Cache retrieval: 5-20ms
• No API calls needed
• Total delay: 5-20ms per page

Improvement: 10-100x faster

API Cost Savings


Example Scenario:

• 10,000 page views/month
• 3 languages
• Without cache: 30,000 API calls
• With cache (95% hit rate): 1,500 API calls
• Savings: 95% reduction in API costs

Monthly Cost Comparison:

• Without cache: ~$60/month (at $20/1M characters)
• With cache: ~$3/month
• Savings: $57/month

Hosting Resource Usage


Memory:

• Cache stored in database or object cache
• Minimal RAM usage
• Object cache (Redis) more efficient than database

CPU:

• Cache hits require minimal processing
• Reduces server load significantly
• Allows handling more concurrent visitors

Database:

• Indexed tables for fast queries
• Minimal database load
• Regular cleanup prevents bloat

Advanced Caching


Object Cache Integration


Supported Systems:

• Redis (recommended for high-traffic sites)
• Memcached
• APCu
• WinCache

Setup:

• Install object cache on server (ask hosting provider)
• Install WordPress object cache plugin (e.g., Redis Object Cache)
• ShahiTranslate Pro auto-detects and uses it
• No additional configuration needed

Benefits:

• 5-10x faster than database cache
• Reduces database load
• Scales better for high traffic

CDN Caching


Compatible CDNs:

• Cloudflare
• KeyCDN
• StackPath
• Amazon CloudFront
• All major CDN providers

How It Works:

• Translated pages cached at CDN edge servers
• Served from location nearest to visitor
• Bypasses your server entirely

Setup:

• Enable language-specific caching on CDN
• Configure cache keys to include language parameter
• Set appropriate cache durations
• Test with multiple languages

Configuration Example (Cloudflare):
`
Cache Key:

• URL with language parameter (/es/, /fr/, etc.)
• Cookie: stp_language

Cache TTL: 1 day
`

Multi-Level Caching Strategy


Level 1 – Browser Cache:

• Visitor’s browser caches pages
• Fastest possible (0ms load time)
• Duration: 1 hour – 1 day

Level 2 – CDN Cache:

• CDN edge servers cache pages
• Very fast (10-50ms)
• Duration: 1 day – 1 week

Level 3 – Server Object Cache:

• Redis/Memcached on your server
• Fast (5-20ms)
• Duration: 1 week – 1 month

Level 4 – Database Cache:

• Stored in WordPress database
• Fast (20-100ms)
• Duration: 1 month – permanent

Result: Maximum performance at every level

Troubleshooting Cache Issues


Cache Not Working


Check:

• Cache is enabled in settings
• Disk space available
• Database tables created properly
• No caching plugin conflicts

Solution:

• Enable cache in settings
• Verify database tables exist
• Check error logs
• Temporarily disable other caching plugins

Stale Content


Issue: Old translations showing after content update

Causes:

• Cache not invalidated on update
• Very long cache duration
• External caching layer not cleared

Solutions:

• Manually clear cache for affected content
• Reduce cache duration
• Configure CDN to purge on update
• Enable automatic cache invalidation

High Storage Usage


Issue: Cache consuming too much disk space

Solutions:

• Reduce cache duration
• Enable auto-cleanup
• Set maximum cache size
• Use compression (enabled by default)
• Limit cached languages

Performance Not Improving


Check:

• Cache hit rate (should be >90%)
• Object cache properly configured
• No database bottlenecks
• CDN working correctly

Solutions:

• Warm cache for popular content
• Optimize database (repair/optimize tables)
• Verify object cache plugin active
• Check CDN configuration

Best Practices


Recommended Settings


For Most Sites:

• Cache Enabled: ✅ Yes
• Duration: 30 days
• Auto-Cleanup: Enabled, weekly
• Object Cache: Use if available
• Cache Warming: Enable for top pages

For High-Traffic Sites:

• Cache Enabled: ✅ Yes
• Duration: 90 days
• Object Cache: Redis (required)
• CDN: Enabled
• Cache Warming: Scheduled, all content

For Frequently Updated Sites:

• Cache Enabled: ✅ Yes
• Duration: 7 days
• Auto-Cleanup: Enabled, daily
• Invalidate on Update: ✅ Yes
• Selective warming: Recent content only

Monitoring


What to Monitor:

• Cache hit rate (aim for 95%+)
• Average page load time
• API usage and costs
• Storage usage
• Error rates

Tools:

• Plugin dashboard
• Google Analytics (page speed)
• Server monitoring (APM tools)
• API provider dashboard (Google Cloud)

Actions Based on Monitoring:

• Low hit rate → Warm cache, increase duration
• High API costs → Check cache working
• Slow pages → Enable object cache, CDN
• High storage → Enable cleanup, reduce duration

Next Steps


• Performance Optimization
• SEO Settings
• Troubleshooting Cache Issues