Data Consistency Models

<h2 id="data-consistency-models" class="position-relative d-flex align-items-center group"> Data Consistency Models <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="data-consistency-models" aria-haspopup="dialog" aria-label="Share link: Data Consistency Models"> Share link </button> </h2><div id="headingShareModal" class="heading-share-modal" role="dialog" aria-modal="true" aria-labelledby="headingShareTitle" hidden> <div class="hsm-dialog" role="document"> <div class="hsm-header"> <h2 id="headingShareTitle" class="h6 mb-0 fw-bold">Share this section</h2> <button type="button" class="hsm-close" aria-label="Close"> </button> </div> <div class="hsm-body"> <label for="headingShareInput" class="form-label small text-muted mb-1 text-uppercase fw-bold" style="font-size: 0.7rem; letter-spacing: 0.5px;">Permalink</label> <div class="input-group mb-4 hsm-url-group"> <input id="headingShareInput" type="text" class="form-control font-monospace" readonly aria-readonly="true" style="font-size: 0.85rem;" /> <button class="btn btn-primary hsm-copy" type="button" aria-label="Copy" title="Copy"> </button> </div> <div class="small fw-bold mb-2 text-muted text-uppercase" style="font-size: 0.7rem; 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'fa-duotone fa-clipboard-check':'fa-duotone fa-circle-exclamation'; setTimeout(()=>{ icon.className=prev; },1800); } function handleShareClick(e){ e.preventDefault(); const btn=e.currentTarget; const id=btn.getAttribute('data-share-target'); if(id) openModal(id); } function bindShareButtons(){ document.querySelectorAll('.h-share').forEach(btn=>{ if(!btn.dataset.hShareBound){ btn.addEventListener('click', handleShareClick); btn.dataset.hShareBound='1'; } }); } bindShareButtons(); if(document.readyState==='loading'){ document.addEventListener('DOMContentLoaded', bindShareButtons); } else { requestAnimationFrame(bindShareButtons); } document.addEventListener('click', function(e){ const shareBtn=e.target.closest && e.target.closest('.h-share'); if(shareBtn && !shareBtn.dataset.hShareBound){ handleShareClick.call(shareBtn, e); } }, true); document.addEventListener('click', e=>{ if(e.target===modal) closeModal(); if(e.target.closest && e.target.closest('.hsm-close')){ e.preventDefault(); closeModal(); } if(copyBtn && (e.target===copyBtn || (e.target.closest && e.target.closest('.hsm-copy')))) { e.preventDefault(); copyCurrent(); } }); document.addEventListener('keydown', e=>{ if(e.key==='Escape' && isOpen()) closeModal(); }); function trapFocus(){ if(trapBound) return; trapBound=true; modal.addEventListener('keydown', f=>{ if(f.key==='Tab' && isOpen()){ const focusable=[...modal.querySelectorAll('a[href],button,input,textarea,select,[tabindex]:not([tabindex="-1"])')].filter(el=>!el.hasAttribute('disabled')); if(!focusable.length) return; const first=focusable[0]; const last=focusable[focusable.length-1]; if(f.shiftKey && document.activeElement===first){ f.preventDefault(); last.focus(); } else if(!f.shiftKey && document.activeElement===last){ f.preventDefault(); first.focus(); } } }); } if(closeBtn) closeBtn.addEventListener('click', e=>{ e.preventDefault(); closeModal(); }); })(); </script>Data consistency is a fundamental concern in distributed graph databases, governing how and when changes become visible across multiple nodes. Geode provides flexible consistency models that allow you to balance between strong guarantees and high performance, depending on your application requirements. This comprehensive guide explores consistency theory, practical implementation strategies, and configuration options for building reliable distributed graph systems. <h3 id="understanding-consistency" class="position-relative d-flex align-items-center group"> Understanding Consistency <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="understanding-consistency" aria-haspopup="dialog" aria-label="Share link: Understanding Consistency"> Share link </button> </h3>In distributed systems, consistency refers to the agreement of data across multiple replicas. When a write operation completes on one node, consistency models define when and how that change becomes visible to readers on other nodes. Different consistency models offer different trade-offs between availability, latency, and correctness guarantees. For graph databases, consistency is particularly important because graph queries often traverse multiple relationships, and inconsistent views can lead to incomplete or incorrect query results. Geode’s consistency mechanisms ensure that graph semantics are preserved even in distributed deployments. <h3 id="consistency-models-in-geode" class="position-relative d-flex align-items-center group"> Consistency Models in Geode <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="consistency-models-in-geode" aria-haspopup="dialog" aria-label="Share link: Consistency Models in Geode"> Share link </button> </h3> <h4 id="strong-consistency-linearizability" class="position-relative d-flex align-items-center group"> Strong Consistency (Linearizability) <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="strong-consistency-linearizability" aria-haspopup="dialog" aria-label="Share link: Strong Consistency (Linearizability)"> Share link </button> </h4>Strong consistency provides the strongest guarantee: every read returns the most recent write, and all operations appear to occur atomically in a global order. This model is essential for applications requiring strict correctness guarantees. Use Cases: <ul> <li>Financial transactions and accounting systems</li> <li>Inventory management with stock tracking</li> <li>Audit logs and compliance systems</li> <li>Critical infrastructure control systems</li> </ul> Configuration: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: # Default consistency model default_model: "strong" # Strong consistency settings strong: # Use synchronous replication replication_mode: "synchronous" # Require acknowledgment from majority write_quorum: "majority" # Read from leader only read_from: "leader" # Timeout for consistency operations timeout_ms: 5000 </code></pre></div>Example Usage: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- This query uses strong consistency by default BEGIN TRANSACTION; MATCH (account:Account {id: $from_id}) SET account.balance = account.balance - $amount; MATCH (dest:Account {id: $to_id}) SET dest.balance = dest.balance + $amount; CREATE (t:Transaction { id: $tx_id, amount: $amount, timestamp: current_timestamp() }) CREATE (account)-[:SENT]->(t) CREATE (t)-[:RECEIVED]->(dest); COMMIT; </code></pre></div> <h4 id="eventual-consistency" class="position-relative d-flex align-items-center group"> Eventual Consistency <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="eventual-consistency" aria-haspopup="dialog" aria-label="Share link: Eventual Consistency"> Share link </button> </h4>Eventual consistency guarantees that if no new updates are made, all replicas will eventually converge to the same state. This model provides high availability and performance at the cost of temporary inconsistencies. Use Cases: <ul> <li>Social media feeds and timelines</li> <li>Analytics and reporting systems</li> <li>Content delivery and caching</li> <li>Collaborative editing with conflict resolution</li> </ul> Configuration: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: default_model: "eventual" eventual: # Maximum staleness tolerance max_staleness_ms: 1000 # Asynchronous replication replication_mode: "asynchronous" # Read from any replica read_from: "any" # Anti-entropy interval anti_entropy_interval_ms: 60000 # Conflict resolution strategy conflict_resolution: "last_write_wins" </code></pre></div>Example Usage: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Query with eventual consistency tolerance MATCH (u:User)-[:FOLLOWS]->(f:User)-[:POSTED]->(p:Post) WHERE u.id = $user_id AND p.created > current_timestamp() - INTERVAL '24' HOUR RETURN p.id, p.content, p.created, f.name ORDER BY p.created DESC LIMIT 100 OPTION (consistency = 'eventual', max_staleness = '5s'); </code></pre></div> <h4 id="causal-consistency" class="position-relative d-flex align-items-center group"> Causal Consistency <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="causal-consistency" aria-haspopup="dialog" aria-label="Share link: Causal Consistency"> Share link </button> </h4>Causal consistency ensures that causally related operations are seen in the same order by all nodes, while allowing concurrent operations to be seen in different orders. This model is ideal for maintaining meaningful ordering without sacrificing performance. Use Cases: <ul> <li>Comment threads and discussions</li> <li>Event sourcing systems</li> <li>Distributed workflow engines</li> <li>Real-time collaboration systems</li> </ul> Configuration: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: default_model: "causal" causal: # Track causality using vector clocks causality_tracking: "vector_clocks" # Session guarantees session_guarantees: read_your_writes: true monotonic_reads: true monotonic_writes: true writes_follow_reads: true # Maximum causality chain length max_chain_length: 1000 </code></pre></div>Example Usage: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Causal consistency for comment thread BEGIN TRANSACTION WITH ISOLATION LEVEL CAUSAL; -- Create parent comment CREATE (parent:Comment { id: $parent_id, content: $parent_content, timestamp: current_timestamp() }); -- Create reply (causally dependent on parent) CREATE (reply:Comment { id: $reply_id, content: $reply_content, timestamp: current_timestamp() }) CREATE (reply)-[:REPLY_TO]->(parent); COMMIT; -- All readers will see parent before reply MATCH (parent:Comment)<-[:REPLY_TO]-(reply:Comment) WHERE parent.id = $parent_id RETURN parent, reply OPTION (consistency = 'causal'); </code></pre></div> <h4 id="tunable-consistency" class="position-relative d-flex align-items-center group"> Tunable Consistency <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="tunable-consistency" aria-haspopup="dialog" aria-label="Share link: Tunable Consistency"> Share link </button> </h4>Tunable consistency allows per-operation control over consistency guarantees, enabling applications to optimize the consistency-performance trade-off for each operation. Configuration: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: # Enable tunable consistency tunable: true # Define consistency levels levels: critical: write_quorum: "all" read_quorum: "quorum" timeout_ms: 10000 standard: write_quorum: "quorum" read_quorum: "one" timeout_ms: 5000 relaxed: write_quorum: "one" read_quorum: "one" timeout_ms: 1000 </code></pre></div>Example Usage: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Critical write with strong guarantees CREATE (order:Order {id: $order_id, status: 'pending'}) OPTION (consistency_level = 'critical'); -- Standard read for display MATCH (order:Order {id: $order_id}) RETURN order OPTION (consistency_level = 'standard'); -- Relaxed read for analytics MATCH (order:Order) WHERE order.created > current_timestamp() - INTERVAL '1' DAY RETURN COUNT(*) as daily_orders OPTION (consistency_level = 'relaxed'); </code></pre></div> <h3 id="session-guarantees" class="position-relative d-flex align-items-center group"> Session Guarantees <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="session-guarantees" aria-haspopup="dialog" aria-label="Share link: Session Guarantees"> Share link </button> </h3>Session guarantees provide consistency within a client session, ensuring predictable behavior across multiple operations. <h4 id="read-your-writes" class="position-relative d-flex align-items-center group"> Read-Your-Writes <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="read-your-writes" aria-haspopup="dialog" aria-label="Share link: Read-Your-Writes"> Share link </button> </h4>Guarantees that a client always sees its own writes: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: session_guarantees: read_your_writes: enabled: true # Track writes per session tracking: "session_based" </code></pre></div><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Write operation CREATE (u:User {id: $user_id, name: $name}) OPTION (session_id = $session_id); -- Immediate read sees the write MATCH (u:User {id: $user_id}) RETURN u.name OPTION (session_id = $session_id); -- Always returns the created user </code></pre></div> <h4 id="monotonic-reads" class="position-relative d-flex align-items-center group"> Monotonic Reads <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="monotonic-reads" aria-haspopup="dialog" aria-label="Share link: Monotonic Reads"> Share link </button> </h4>Ensures that successive reads return increasingly up-to-date data: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: session_guarantees: monotonic_reads: enabled: true # Use read timestamps mechanism: "read_timestamps" </code></pre></div> <h4 id="monotonic-writes" class="position-relative d-flex align-items-center group"> Monotonic Writes <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="monotonic-writes" aria-haspopup="dialog" aria-label="Share link: Monotonic Writes"> Share link </button> </h4>Guarantees that writes from a session are applied in order: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: session_guarantees: monotonic_writes: enabled: true # Order writes per session ordering: "session_sequence" </code></pre></div> <h3 id="consistency-and-transactions" class="position-relative d-flex align-items-center group"> Consistency and Transactions <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="consistency-and-transactions" aria-haspopup="dialog" aria-label="Share link: Consistency and Transactions"> Share link </button> </h3> <h4 id="acid-properties" class="position-relative d-flex align-items-center group"> ACID Properties <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="acid-properties" aria-haspopup="dialog" aria-label="Share link: ACID Properties"> Share link </button> </h4>Geode transactions provide full ACID guarantees: Atomicity: All operations in a transaction succeed or fail together. Consistency: Transactions move the database from one valid state to another. Isolation: Concurrent transactions don’t interfere with each other. Durability: Committed transactions are permanently stored. <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">transactions: # Isolation levels isolation: default_level: "serializable" levels: - read_uncommitted - read_committed - repeatable_read - snapshot - serializable # Durability settings durability: # Sync to disk before commit fsync_mode: "always" # Write-ahead logging wal: enabled: true sync_mode: "synchronous" </code></pre></div> <h4 id="transaction-isolation-levels" class="position-relative d-flex align-items-center group"> Transaction Isolation Levels <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="transaction-isolation-levels" aria-haspopup="dialog" aria-label="Share link: Transaction Isolation Levels"> Share link </button> </h4>Configure isolation level for consistency guarantees: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Serializable isolation (strongest) BEGIN TRANSACTION WITH ISOLATION LEVEL SERIALIZABLE; MATCH (a:Account {id: $id}) SET a.balance = a.balance + $amount; COMMIT; -- Snapshot isolation (good performance) BEGIN TRANSACTION WITH ISOLATION LEVEL SNAPSHOT; MATCH (u:User)-[:FOLLOWS]->(f:User) RETURN COUNT(DISTINCT f) as follower_count; COMMIT; -- Read committed (minimal locking) BEGIN TRANSACTION WITH ISOLATION LEVEL READ COMMITTED; MATCH (p:Product {id: $id}) RETURN p.price, p.inventory; COMMIT; </code></pre></div> <h3 id="quorum-based-consistency" class="position-relative d-flex align-items-center group"> Quorum-Based Consistency <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="quorum-based-consistency" aria-haspopup="dialog" aria-label="Share link: Quorum-Based Consistency"> Share link </button> </h3>Geode uses quorum mechanisms to balance consistency and availability: <h4 id="read-and-write-quorums" class="position-relative d-flex align-items-center group"> Read and Write Quorums <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="read-and-write-quorums" aria-haspopup="dialog" aria-label="Share link: Read and Write Quorums"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: quorum: # Number of replicas replication_factor: 3 # Write quorum (W) write_quorum: 2 # Read quorum (R) read_quorum: 2 # Ensure W + R > N for strong consistency validate_quorum: true </code></pre></div>Strong Consistency: Set <code>W + R > N</code> where N is replication factor. High Availability: Set <code>W + R ≤ N</code> for better availability. <h4 id="quorum-configuration-examples" class="position-relative d-flex align-items-center group"> Quorum Configuration Examples <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="quorum-configuration-examples" aria-haspopup="dialog" aria-label="Share link: Quorum Configuration Examples"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml"># Strong consistency (W=3, R=1, N=3) # All writes must succeed before acknowledgment # Reads always return latest data strong_consistency: replication_factor: 3 write_quorum: 3 read_quorum: 1 # Balanced (W=2, R=2, N=3) # Tolerates one node failure # Strong consistency with good performance balanced: replication_factor: 3 write_quorum: 2 read_quorum: 2 # High availability (W=1, R=1, N=3) # Tolerates two node failures # Eventual consistency high_availability: replication_factor: 3 write_quorum: 1 read_quorum: 1 </code></pre></div> <h3 id="conflict-resolution" class="position-relative d-flex align-items-center group"> Conflict Resolution <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="conflict-resolution" aria-haspopup="dialog" aria-label="Share link: Conflict Resolution"> Share link </button> </h3>When eventual consistency allows conflicts, Geode provides resolution strategies: <h4 id="last-write-wins-lww" class="position-relative d-flex align-items-center group"> Last-Write-Wins (LWW) <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="last-write-wins-lww" aria-haspopup="dialog" aria-label="Share link: Last-Write-Wins (LWW)"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: conflict_resolution: strategy: "last_write_wins" # Use logical clocks for ordering timestamp_source: "hybrid_logical_clock" # Conflict detection window detection_window_ms: 1000 </code></pre></div> <h4 id="multi-value-registers" class="position-relative d-flex align-items-center group"> Multi-Value Registers <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="multi-value-registers" aria-haspopup="dialog" aria-label="Share link: Multi-Value Registers"> Share link </button> </h4>Keep all conflicting values and let application resolve: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: conflict_resolution: strategy: "multi_value" # Maximum concurrent values to track max_values: 10 # Expose conflicts to application expose_conflicts: true </code></pre></div> <h4 id="custom-conflict-resolution" class="position-relative d-flex align-items-center group"> Custom Conflict Resolution <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="custom-conflict-resolution" aria-haspopup="dialog" aria-label="Share link: Custom Conflict Resolution"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">consistency: conflict_resolution: strategy: "custom" # User-defined resolution function resolver: "merge_by_priority" # Conflict resolution metadata metadata_properties: - priority - source_node - timestamp </code></pre></div> <h3 id="monitoring-consistency" class="position-relative d-flex align-items-center group"> Monitoring Consistency <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="monitoring-consistency" aria-haspopup="dialog" aria-label="Share link: Monitoring Consistency"> Share link </button> </h3> <h4 id="consistency-metrics" class="position-relative d-flex align-items-center group"> Consistency Metrics <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="consistency-metrics" aria-haspopup="dialog" aria-label="Share link: Consistency Metrics"> Share link </button> </h4>Track consistency-related metrics: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-yaml" data-lang="yaml">monitoring: consistency_metrics: enabled: true # Metrics to collect metrics: - replication_lag_ms - consistency_violations_total - quorum_failures_total - conflict_resolutions_total - stale_reads_total - transaction_aborts_by_isolation_level # Export to Prometheus prometheus: enabled: true port: 9090 </code></pre></div>Key metrics to monitor: <ul> <li><code>geode_replication_lag_ms</code>: Time lag between primary and replicas</li> <li><code>geode_consistency_violations_total</code>: Detected consistency violations</li> <li><code>geode_quorum_failures_total</code>: Failed quorum operations</li> <li><code>geode_stale_reads_total</code>: Reads that returned stale data</li> <li><code>geode_transaction_conflicts_total</code>: Transaction conflicts</li> </ul> <h4 id="consistency-verification" class="position-relative d-flex align-items-center group"> Consistency Verification <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="consistency-verification" aria-haspopup="dialog" aria-label="Share link: Consistency Verification"> Share link </button> </h4>Verify consistency across replicas: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-bash" data-lang="bash"># Check replica consistency geode consistency verify \ --graph=production \ --sample-rate=0.1 \ --report=consistency-report.json # Measure replication lag geode consistency lag \ --graph=production \ --interval=10s # Detect consistency violations geode consistency detect-violations \ --graph=production \ --window=1h </code></pre></div> <h3 id="best-practices" class="position-relative d-flex align-items-center group"> Best Practices <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="best-practices" aria-haspopup="dialog" aria-label="Share link: Best Practices"> Share link </button> </h3> <h4 id="choosing-consistency-models" class="position-relative d-flex align-items-center group"> Choosing Consistency Models <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="choosing-consistency-models" aria-haspopup="dialog" aria-label="Share link: Choosing Consistency Models"> Share link </button> </h4><ol> <li> Default to Strong Consistency: Use strong consistency unless you have specific performance requirements and can tolerate stale reads. </li> <li> Use Eventual Consistency for Analytics: Read-heavy analytical queries can often tolerate eventual consistency for better performance. </li> <li> Apply Causal Consistency for Ordering: When operation ordering matters but strict consistency is not required, use causal consistency. </li> <li> Tune Per-Operation: Use tunable consistency to optimize critical paths while relaxing guarantees for non-critical operations. </li> </ol> <h4 id="configuration-guidelines" class="position-relative d-flex align-items-center group"> Configuration Guidelines <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="configuration-guidelines" aria-haspopup="dialog" aria-label="Share link: Configuration Guidelines"> Share link </button> </h4><ul> <li>Start with strong consistency and relax only when necessary</li> <li>Monitor replication lag and set appropriate staleness thresholds</li> <li>Configure session guarantees for multi-operation workflows</li> <li>Use appropriate isolation levels for transaction workloads</li> <li>Set quorum values based on availability requirements</li> </ul> <h4 id="testing-consistency" class="position-relative d-flex align-items-center group"> Testing Consistency <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="testing-consistency" aria-haspopup="dialog" aria-label="Share link: Testing Consistency"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-bash" data-lang="bash"># Inject delays to test eventual consistency geode consistency test \ --scenario=delayed_replication \ --delay-ms=1000 \ --duration=5m # Simulate network partitions geode consistency test \ --scenario=network_partition \ --partition-nodes=node1,node2 # Verify ACID properties geode consistency test \ --scenario=acid_compliance \ --isolation-level=serializable </code></pre></div> <h3 id="troubleshooting" class="position-relative d-flex align-items-center group"> Troubleshooting <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="troubleshooting" aria-haspopup="dialog" aria-label="Share link: Troubleshooting"> Share link </button> </h3> <h4 id="common-consistency-issues" class="position-relative d-flex align-items-center group"> Common Consistency Issues <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="common-consistency-issues" aria-haspopup="dialog" aria-label="Share link: Common Consistency Issues"> Share link </button> </h4>Stale Reads: Clients reading outdated data. Solution: Increase read quorum, reduce staleness tolerance, or use strong consistency. Replication Lag: Replicas falling behind primary. Solution: Increase replication bandwidth, reduce write throughput, or add more replicas. Quorum Failures: Unable to achieve quorum for operations. Solution: Reduce quorum requirements, add more nodes, or investigate network issues. Transaction Conflicts: High abort rates due to conflicts. Solution: Reduce transaction scope, use optimistic locking, or adjust isolation level. <h4 id="diagnostic-queries" class="position-relative d-flex align-items-center group"> Diagnostic Queries <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="diagnostic-queries" aria-haspopup="dialog" aria-label="Share link: Diagnostic Queries"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Check replication status CALL dbms.cluster.replication_status() YIELD node_id, lag_ms, status; -- View active transactions CALL dbms.transactions.list() YIELD transaction_id, isolation_level, start_time; -- Check consistency configuration CALL dbms.config.get('consistency.*') YIELD key, value; </code></pre></div> <h3 id="cap-theorem-considerations" class="position-relative d-flex align-items-center group"> CAP Theorem Considerations <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="cap-theorem-considerations" aria-haspopup="dialog" aria-label="Share link: CAP Theorem Considerations"> Share link </button> </h3>In distributed systems, the CAP theorem states you can have at most two of: <ul> <li>Consistency: All nodes see the same data</li> <li>Availability: All requests receive a response</li> <li>Partition Tolerance: System continues despite network partitions</li> </ul> Geode’s consistency models map to CAP choices: Strong Consistency (CP): Prioritizes consistency and partition tolerance, may sacrifice availability during partitions. Eventual Consistency (AP): Prioritizes availability and partition tolerance, allows temporary inconsistencies. Tunable Consistency: Allows per-operation trade-offs between CP and AP. <h3 id="related-topics" class="position-relative d-flex align-items-center group"> Related Topics <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="related-topics" aria-haspopup="dialog" aria-label="Share link: Related Topics"> Share link </button> </h3><ul> <li><a href="/tags/clustering/" >Clustering</a> - Database clustering and multi-node deployment</li> <li><a href="/tags/replication/" >Replication</a> - Data replication strategies</li> <li><a href="/tags/transactions/" >Transactions</a> - Transaction management and ACID properties</li> <li><a href="/tags/performance/" >Performance</a> - Performance optimization</li> </ul> <h3 id="further-reading" class="position-relative d-flex align-items-center group"> Further Reading <button type="button" class="h-share btn btn-link p-0 text-decoration-none link-secondary opacity-50 hover-opacity-100 transition-all ms-1" data-share-target="further-reading" aria-haspopup="dialog" aria-label="Share link: Further Reading"> Share link </button> </h3><ul> <li><a href="/docs/architecture/distributed-architecture/" >Distributed Architecture</a> - Distributed systems design</li> <li><a href="/docs/transactions/advanced-patterns/" >Transaction Patterns</a> - Advanced transaction usage</li> <li><a href="/docs/architecture/distributed-systems/" >Distributed Systems</a> - Distributed systems architecture</li> </ul>

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