Transaction Patterns Tutorial

<h2 id="transaction-patterns-tutorial" class="position-relative d-flex align-items-center group"> Transaction Patterns Tutorial <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-patterns-tutorial" aria-haspopup="dialog" aria-label="Share link: Transaction Patterns Tutorial"> 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; letter-spacing: 0.5px;">Share via</div> <div class="hsm-share-grid"> <a id="share-twitter" class="btn btn-outline-secondary w-100" target="_blank" rel="noopener noreferrer"> Twitter </a> <a id="share-linkedin" class="btn btn-outline-secondary w-100" target="_blank" rel="noopener noreferrer"> LinkedIn </a> <a id="share-facebook" class="btn btn-outline-secondary w-100" target="_blank" rel="noopener noreferrer"> Facebook </a> </div> </div> </div> </div> <style> .heading-share-modal { position: fixed; inset: 0; display: flex; justify-content: center; align-items: center; background: rgba(0, 0, 0, 0.6); z-index: 1050; padding: 1rem; backdrop-filter: blur(4px); -webkit-backdrop-filter: blur(4px); } .heading-share-modal[hidden] { display: none !important; } .hsm-dialog { max-width: 420px; width: 100%; background: var(--bs-body-bg, #fff); color: var(--bs-body-color, #212529); border: 1px solid var(--bs-border-color, rgba(0,0,0,0.1)); border-radius: 1rem; box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25); overflow: hidden; animation: hsm-fade-in 0.2s ease-out; } @keyframes hsm-fade-in { from { opacity: 0; transform: scale(0.95); } to { opacity: 1; transform: scale(1); } } [data-bs-theme="dark"] .hsm-dialog { background: #1e293b; border-color: rgba(255,255,255,0.1); color: #f8f9fa; } .hsm-header { display: flex; justify-content: space-between; align-items: center; padding: 1rem 1.5rem; border-bottom: 1px solid var(--bs-border-color, rgba(0,0,0,0.1)); background: rgba(0,0,0,0.02); } [data-bs-theme="dark"] .hsm-header { background: rgba(255,255,255,0.02); border-color: rgba(255,255,255,0.1); } .hsm-close { background: transparent; border: none; color: inherit; opacity: 0.5; padding: 0.25rem 0.5rem; border-radius: 0.25rem; font-size: 1.2rem; line-height: 1; transition: opacity 0.2s; } .hsm-close:hover { opacity: 1; } .hsm-body { padding: 1.5rem; } .hsm-url-group { display: flex !important; align-items: stretch; } .hsm-url-group .form-control { flex: 1; min-width: 0; margin: 0; background: var(--bs-secondary-bg, #f8f9fa); border-color: var(--bs-border-color, #dee2e6); border-top-right-radius: 0; border-bottom-right-radius: 0; height: 42px; } .hsm-url-group .btn { flex: 0 0 auto; margin: 0; margin-left: -1px; border-top-left-radius: 0; border-bottom-left-radius: 0; height: 42px; display: flex; align-items: center; justify-content: center; padding: 0 1.25rem; z-index: 2; } [data-bs-theme="dark"] .hsm-url-group .form-control { background: #0f172a; border-color: #334155; color: #e2e8f0; } .hsm-share-grid { display: flex; flex-direction: column; gap: 0.5rem; } .hsm-share-grid .btn { display: flex; align-items: center; justify-content: center; font-size: 0.9rem; padding: 0.6rem; border-color: var(--bs-border-color); width: 100%; } [data-bs-theme="dark"] .hsm-share-grid .btn { color: #e2e8f0; border-color: #475569; } [data-bs-theme="dark"] .hsm-share-grid .btn:hover { background: #334155; border-color: #cbd5e1; } </style> <script> (function(){ const modal = document.getElementById('headingShareModal'); if(!modal) return; const input = modal.querySelector('#headingShareInput'); const copyBtn = modal.querySelector('.hsm-copy'); const twitter = modal.querySelector('#share-twitter'); const linkedin = modal.querySelector('#share-linkedin'); const facebook = modal.querySelector('#share-facebook'); const closeBtn = modal.querySelector('.hsm-close'); let lastFocus=null; let trapBound=false; function buildUrl(id){ return window.location.origin + window.location.pathname + '#' + id; } function isOpen(){ return !modal.hasAttribute('hidden'); } function hydrate(id){ const url=buildUrl(id); input.value=url; const enc=encodeURIComponent(url); const text=encodeURIComponent(document.title); if(twitter) twitter.href=`https://twitter.com/intent/tweet?url=${enc}&text=${text}`; if(linkedin) linkedin.href=`https://www.linkedin.com/sharing/share-offsite/?url=${enc}`; if(facebook) facebook.href=`https://www.facebook.com/sharer/sharer.php?u=${enc}`; } function openModal(id){ lastFocus=document.activeElement; hydrate(id); if(!isOpen()){ modal.removeAttribute('hidden'); } requestAnimationFrame(()=>{ input.focus(); }); trapFocus(); } function closeModal(){ if(!isOpen()) return; modal.setAttribute('hidden',''); if(lastFocus && typeof lastFocus.focus==='function') lastFocus.focus(); } function copyCurrent(){ try{ navigator.clipboard.writeText(input.value).then(()=>feedback(true),()=>fallback()); } catch(e){ fallback(); } } function fallback(){ input.select(); try{ document.execCommand('copy'); feedback(true);}catch(e){ feedback(false);} } function feedback(ok){ if(!copyBtn) return; const icon=copyBtn.querySelector('i'); if(!icon) return; const prev=copyBtn.getAttribute('data-prev')||icon.className; if(!copyBtn.getAttribute('data-prev')) copyBtn.setAttribute('data-prev',prev); icon.className= ok ? '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>Master ACID transactions and isolation levels in Geode in this hands-on 30-minute tutorial. <h3 id="prerequisites" class="position-relative d-flex align-items-center group"> Prerequisites <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="prerequisites" aria-haspopup="dialog" aria-label="Share link: Prerequisites"> Share link </button> </h3><ul> <li>Completed <a href="/docs/tutorials/match-basics/" >MATCH Basics Tutorial</a> </li> <li>Geode server running (<code>geode serve</code>)</li> <li>Access to Geode shell (<code>geode shell</code>)</li> <li>Understanding of basic SQL transactions (helpful but not required)</li> </ul> <h3 id="tutorial-overview" class="position-relative d-flex align-items-center group"> Tutorial Overview <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="tutorial-overview" aria-haspopup="dialog" aria-label="Share link: Tutorial Overview"> Share link </button> </h3>Time: 30 minutes Difficulty: Intermediate Topics: ACID properties, isolation levels, savepoints, deadlock handling By the end of this tutorial, you’ll be able to: <ul> <li>Use transactions for data consistency</li> <li>Choose appropriate isolation levels</li> <li>Handle concurrent updates safely</li> <li>Use savepoints for partial rollback</li> <li>Debug and resolve deadlocks</li> <li>Implement common transaction patterns</li> </ul> <h3 id="what-are-transactions" class="position-relative d-flex align-items-center group"> What are 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="what-are-transactions" aria-haspopup="dialog" aria-label="Share link: What are Transactions?"> Share link </button> </h3>Transactions group multiple operations into a single atomic unit. Either all operations succeed (commit) or none do (rollback), ensuring data consistency. <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><ul> <li>Atomicity: All or nothing - operations complete fully or not at all</li> <li>Consistency: Data remains valid before and after transaction</li> <li>Isolation: Concurrent transactions don’t interfere</li> <li>Durability: Committed data survives crashes</li> </ul> <h3 id="step-1-basic-transactions" class="position-relative d-flex align-items-center group"> Step 1: Basic 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="step-1-basic-transactions" aria-haspopup="dialog" aria-label="Share link: Step 1: Basic Transactions"> Share link </button> </h3> <h4 id="start-commit-rollback" class="position-relative d-flex align-items-center group"> Start, Commit, Rollback <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="start-commit-rollback" aria-haspopup="dialog" aria-label="Share link: Start, Commit, Rollback"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Start a transaction START TRANSACTION; -- Create data CREATE (:Account {id: 1, name: 'Alice', balance: 1000}); CREATE (:Account {id: 2, name: 'Bob', balance: 500}); -- Commit to make changes permanent COMMIT; </code></pre></div>Verify: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">MATCH (a:Account) RETURN a.name, a.balance; </code></pre></div>Expected output: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback">name | balance ------|-------- Alice | 1000 Bob | 500 </code></pre></div> <h4 id="rollback-on-error" class="position-relative d-flex align-items-center group"> Rollback on Error <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="rollback-on-error" aria-haspopup="dialog" aria-label="Share link: Rollback on Error"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Start transaction START TRANSACTION; -- Create node CREATE (:Account {id: 3, name: 'Carol', balance: 750}); -- Decide to cancel ROLLBACK; -- Verify Carol was NOT created MATCH (a:Account {name: 'Carol'}) RETURN a; -- Returns 0 rows </code></pre></div> <h4 id="client-library-examples" class="position-relative d-flex align-items-center group"> Client Library 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="client-library-examples" aria-haspopup="dialog" aria-label="Share link: Client Library Examples"> Share link </button> </h4><div class="docs-tabs mb-4"> <ul class="nav nav-tabs" id="tabs-1774880892041575361" role="tablist"><li class="nav-item" role="presentation"> <button class="nav-link active" id="tabs-1774880892041575361-tab-0-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892041575361-tab-0" type="button" role="tab" aria-controls="tabs-1774880892041575361-tab-0" aria-selected="true" > Go </button> </li><li class="nav-item" role="presentation"> <button class="nav-link" id="tabs-1774880892041575361-tab-1-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892041575361-tab-1" type="button" role="tab" aria-controls="tabs-1774880892041575361-tab-1" aria-selected="false" > Python </button> </li><li class="nav-item" role="presentation"> <button class="nav-link" id="tabs-1774880892041575361-tab-2-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892041575361-tab-2" type="button" role="tab" aria-controls="tabs-1774880892041575361-tab-2" aria-selected="false" > Rust </button> </li><li class="nav-item" role="presentation"> <button class="nav-link" id="tabs-1774880892041575361-tab-3-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892041575361-tab-3" type="button" role="tab" aria-controls="tabs-1774880892041575361-tab-3" aria-selected="false" > Node.js </button> </li><li class="nav-item" role="presentation"> <button class="nav-link" id="tabs-1774880892041575361-tab-4-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892041575361-tab-4" type="button" role="tab" aria-controls="tabs-1774880892041575361-tab-4" aria-selected="false" > Zig </button> </li></ul> <div class="tab-content border border-top-0 rounded-bottom p-3" id="tabs-1774880892041575361-content"><div class="tab-pane fade show active" id="tabs-1774880892041575361-tab-0" role="tabpanel" aria-labelledby="tabs-1774880892041575361-tab-0-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go">// Start transaction tx, err := db.BeginTx(ctx, nil) if err != nil { log.Fatal(err) } // Create accounts _, err = tx.ExecContext(ctx, `CREATE (:Account {id: ?, name: ?, balance: ?})`, 1, "Alice", 1000) if err != nil { tx.Rollback() log.Fatal(err) } _, err = tx.ExecContext(ctx, `CREATE (:Account {id: ?, name: ?, balance: ?})`, 2, "Bob", 500) if err != nil { tx.Rollback() log.Fatal(err) } // Commit if err := tx.Commit(); err != nil { log.Fatal(err) } </code></pre></div> </div><div class="tab-pane fade" id="tabs-1774880892041575361-tab-1" role="tabpanel" aria-labelledby="tabs-1774880892041575361-tab-1-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-python" data-lang="python">async with client.connection() as conn: await conn.begin() try: await conn.execute( "CREATE (:Account {id: $id, name: $name, balance: $balance})", {"id": 1, "name": "Alice", "balance": 1000} ) await conn.execute( "CREATE (:Account {id: $id, name: $name, balance: $balance})", {"id": 2, "name": "Bob", "balance": 500} ) await conn.commit() except Exception: await conn.rollback() raise </code></pre></div> </div><div class="tab-pane fade" id="tabs-1774880892041575361-tab-2" role="tabpanel" aria-labelledby="tabs-1774880892041575361-tab-2-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-rust" data-lang="rust">conn.begin().await?; match async { conn.query_with_params( "CREATE (:Account {id: $id, name: $name, balance: $balance})", &[("id", Value::int(1)), ("name", Value::string("Alice")), ("balance", Value::int(1000))].into() ).await?; conn.query_with_params( "CREATE (:Account {id: $id, name: $name, balance: $balance})", &[("id", Value::int(2)), ("name", Value::string("Bob")), ("balance", Value::int(500))].into() ).await?; conn.commit().await }.await { Ok(_) => println!("Accounts created"), Err(e) => { conn.rollback().await?; return Err(e); } } </code></pre></div> </div><div class="tab-pane fade" id="tabs-1774880892041575361-tab-3" role="tabpanel" aria-labelledby="tabs-1774880892041575361-tab-3-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript">await client.withTransaction(async (tx) => { await tx.exec( 'CREATE (:Account {id: $id, name: $name, balance: $balance})', { params: { id: 1, name: 'Alice', balance: 1000 } } ); await tx.exec( 'CREATE (:Account {id: $id, name: $name, balance: $balance})', { params: { id: 2, name: 'Bob', balance: 500 } } ); // Auto-commits on success, auto-rollback on error }); </code></pre></div> </div><div class="tab-pane fade" id="tabs-1774880892041575361-tab-4" role="tabpanel" aria-labelledby="tabs-1774880892041575361-tab-4-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-zig" data-lang="zig">try client.sendBegin(); _ = try client.receiveMessage(30000); // Create accounts with parameterized queries var params = std.json.ObjectMap.init(allocator); defer params.deinit(); try params.put("id", .{ .integer = 1 }); try params.put("name", .{ .string = "Alice" }); try params.put("balance", .{ .integer = 1000 }); try client.sendRunGql(1, "CREATE (:Account {id: $id, name: $name, balance: $balance})", .{ .object = params }); _ = try client.receiveMessage(30000); params.clearRetainingCapacity(); try params.put("id", .{ .integer = 2 }); try params.put("name", .{ .string = "Bob" }); try params.put("balance", .{ .integer = 500 }); try client.sendRunGql(2, "CREATE (:Account {id: $id, name: $name, balance: $balance})", .{ .object = params }); _ = try client.receiveMessage(30000); try client.sendCommit(); _ = try client.receiveMessage(30000); </code></pre></div> </div></div> </div> <h4 id="what-you-learned" class="position-relative d-flex align-items-center group"> What You Learned <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="what-you-learned" aria-haspopup="dialog" aria-label="Share link: What You Learned"> Share link </button> </h4><ul> <li><code>START TRANSACTION</code> begins a transaction</li> <li><code>COMMIT</code> makes changes permanent</li> <li><code>ROLLBACK</code> discards all changes</li> <li>Changes are invisible to other connections until commit</li> </ul> <h3 id="step-2-money-transfer-pattern" class="position-relative d-flex align-items-center group"> Step 2: Money Transfer Pattern <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="step-2-money-transfer-pattern" aria-haspopup="dialog" aria-label="Share link: Step 2: Money Transfer Pattern"> Share link </button> </h3> <h4 id="atomic-transfer" class="position-relative d-flex align-items-center group"> Atomic Transfer <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="atomic-transfer" aria-haspopup="dialog" aria-label="Share link: Atomic Transfer"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Transfer $100 from Alice to Bob START TRANSACTION; -- Debit sender MATCH (alice:Account {name: 'Alice'}) SET alice.balance = alice.balance - 100; -- Credit receiver MATCH (bob:Account {name: 'Bob'}) SET bob.balance = bob.balance + 100; -- Both updates happen or neither does COMMIT; -- Verify MATCH (a:Account) RETURN a.name, a.balance ORDER BY a.name; </code></pre></div>Expected output: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback">name | balance ------|-------- Alice | 900 Bob | 600 </code></pre></div> <h4 id="with-validation" class="position-relative d-flex align-items-center group"> With Validation <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="with-validation" aria-haspopup="dialog" aria-label="Share link: With Validation"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Transfer with insufficient funds check START TRANSACTION; -- Check sender balance MATCH (alice:Account {name: 'Alice'}) WHERE alice.balance >= 200 SET alice.balance = alice.balance - 200; -- If no rows matched, balance was insufficient -- Transaction still continues but with no changes -- Credit receiver MATCH (bob:Account {name: 'Bob'}) SET bob.balance = bob.balance + 200; COMMIT; </code></pre></div> <h4 id="error-handling-pattern" class="position-relative d-flex align-items-center group"> Error Handling Pattern <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="error-handling-pattern" aria-haspopup="dialog" aria-label="Share link: Error Handling Pattern"> Share link </button> </h4><div class="docs-tabs mb-4"> <ul class="nav nav-tabs" id="tabs-1774880892056424642" role="tablist"><li class="nav-item" role="presentation"> <button class="nav-link active" id="tabs-1774880892056424642-tab-0-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892056424642-tab-0" type="button" role="tab" aria-controls="tabs-1774880892056424642-tab-0" aria-selected="true" > Go </button> </li><li class="nav-item" role="presentation"> <button class="nav-link" id="tabs-1774880892056424642-tab-1-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892056424642-tab-1" type="button" role="tab" aria-controls="tabs-1774880892056424642-tab-1" aria-selected="false" > Python </button> </li><li class="nav-item" role="presentation"> <button class="nav-link" id="tabs-1774880892056424642-tab-2-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892056424642-tab-2" type="button" role="tab" aria-controls="tabs-1774880892056424642-tab-2" aria-selected="false" > Rust </button> </li><li class="nav-item" role="presentation"> <button class="nav-link" id="tabs-1774880892056424642-tab-3-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892056424642-tab-3" type="button" role="tab" aria-controls="tabs-1774880892056424642-tab-3" aria-selected="false" > Node.js </button> </li><li class="nav-item" role="presentation"> <button class="nav-link" id="tabs-1774880892056424642-tab-4-tab" data-bs-toggle="tab" data-bs-target="#tabs-1774880892056424642-tab-4" type="button" role="tab" aria-controls="tabs-1774880892056424642-tab-4" aria-selected="false" > Zig </button> </li></ul> <div class="tab-content border border-top-0 rounded-bottom p-3" id="tabs-1774880892056424642-content"><div class="tab-pane fade show active" id="tabs-1774880892056424642-tab-0" role="tabpanel" aria-labelledby="tabs-1774880892056424642-tab-0-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-go" data-lang="go">func transferMoney(ctx context.Context, db *sql.DB, from, to string, amount int) error { tx, err := db.BeginTx(ctx, nil) if err != nil { return err } // Check balance var balance int err = tx.QueryRowContext(ctx, "MATCH (a:Account {name: ?}) RETURN a.balance", from).Scan(&balance) if err != nil { tx.Rollback() return err } if balance < amount { tx.Rollback() return fmt.Errorf("insufficient funds in %s", from) } // Debit sender _, err = tx.ExecContext(ctx, "MATCH (a:Account {name: ?}) SET a.balance = a.balance - ?", from, amount) if err != nil { tx.Rollback() return err } // Credit receiver _, err = tx.ExecContext(ctx, "MATCH (a:Account {name: ?}) SET a.balance = a.balance + ?", to, amount) if err != nil { tx.Rollback() return err } return tx.Commit() } </code></pre></div> </div><div class="tab-pane fade" id="tabs-1774880892056424642-tab-1" role="tabpanel" aria-labelledby="tabs-1774880892056424642-tab-1-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-python" data-lang="python">async def transfer_money(from_account, to_account, amount): async with client.connection() as conn: try: await conn.begin() page, _ = await conn.query( "MATCH (a:Account {name: $from}) RETURN a.balance AS balance", {"from": from_account}, ) if not page.rows or page.rows[0]["balance"].as_int < amount: raise ValueError(f"Insufficient funds in {from_account}") await conn.execute( "MATCH (a:Account {name: $from}) SET a.balance = a.balance - $amount", {"from": from_account, "amount": amount}, ) await conn.execute( "MATCH (a:Account {name: $to}) SET a.balance = a.balance + $amount", {"to": to_account, "amount": amount}, ) await conn.commit() except Exception: await conn.rollback() raise </code></pre></div> </div><div class="tab-pane fade" id="tabs-1774880892056424642-tab-2" role="tabpanel" aria-labelledby="tabs-1774880892056424642-tab-2-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-rust" data-lang="rust">async fn transfer_money(conn: &mut Connection, from: &str, to: &str, amount: i64) -> Result<()> { conn.begin().await?; // Check balance let params = [("from", Value::string(from))].into(); let (page, _) = conn.query_with_params( "MATCH (a:Account {name: $from}) RETURN a.balance AS balance", &params ).await?; let balance = page.rows.first() .and_then(|r| r.get("balance")) .map(|v| v.as_int().unwrap_or(0)) .unwrap_or(0); if balance < amount { conn.rollback().await?; return Err("Insufficient funds".into()); } // Transfer let mut params = HashMap::new(); params.insert("from".to_string(), Value::string(from)); params.insert("to".to_string(), Value::string(to)); params.insert("amount".to_string(), Value::int(amount)); conn.query_with_params("MATCH (a:Account {name: $from}) SET a.balance = a.balance - $amount", &params).await?; conn.query_with_params("MATCH (a:Account {name: $to}) SET a.balance = a.balance + $amount", &params).await?; conn.commit().await } </code></pre></div> </div><div class="tab-pane fade" id="tabs-1774880892056424642-tab-3" role="tabpanel" aria-labelledby="tabs-1774880892056424642-tab-3-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript">async function transferMoney(from: string, to: string, amount: number) { const conn = await client.getConnection(); const tx = await conn.begin(); try { // Check balance const [row] = await tx.queryAll( 'MATCH (a:Account {name: $from}) RETURN a.balance AS balance', { params: { from } } ); const balance = row?.get('balance')?.asNumber ?? 0; if (balance < amount) { throw new Error(`Insufficient funds in ${from}`); } // Debit sender await tx.exec( 'MATCH (a:Account {name: $from}) SET a.balance = a.balance - $amount', { params: { from, amount } } ); // Credit receiver await tx.exec( 'MATCH (a:Account {name: $to}) SET a.balance = a.balance + $amount', { params: { to, amount } } ); await tx.commit(); } catch (e) { await tx.rollback(); throw e; } finally { await client.releaseConnection(conn); } } </code></pre></div> </div><div class="tab-pane fade" id="tabs-1774880892056424642-tab-4" role="tabpanel" aria-labelledby="tabs-1774880892056424642-tab-4-tab" > <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-zig" data-lang="zig">fn transferMoney(client: *GeodeClient, allocator: std.mem.Allocator, from: []const u8, to: []const u8, amount: i64) !void { try client.sendBegin(); _ = try client.receiveMessage(30000); var params = std.json.ObjectMap.init(allocator); defer params.deinit(); try params.put("from", .{ .string = from }); try params.put("to", .{ .string = to }); try params.put("amount", .{ .integer = amount }); // Check balance try client.sendRunGql(1, "MATCH (a:Account {name: $from}) RETURN a.balance AS balance", .{ .object = params }); const schema = try client.receiveMessage(30000); allocator.free(schema); try client.sendPull(1, 1000); const balance_result = try client.receiveMessage(30000); defer allocator.free(balance_result); // Parse and validate balance >= amount before proceeding // Debit sender try client.sendRunGql(2, "MATCH (a:Account {name: $from}) SET a.balance = a.balance - $amount", .{ .object = params }); _ = try client.receiveMessage(30000); // Credit receiver try client.sendRunGql(3, "MATCH (a:Account {name: $to}) SET a.balance = a.balance + $amount", .{ .object = params }); _ = try client.receiveMessage(30000); try client.sendCommit(); _ = try client.receiveMessage(30000); } </code></pre></div> </div></div> </div> <h3 id="step-3-savepoints-partial-rollback" class="position-relative d-flex align-items-center group"> Step 3: Savepoints (Partial Rollback) <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="step-3-savepoints-partial-rollback" aria-haspopup="dialog" aria-label="Share link: Step 3: Savepoints (Partial Rollback)"> Share link </button> </h3> <h4 id="create-savepoints" class="position-relative d-flex align-items-center group"> Create Savepoints <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="create-savepoints" aria-haspopup="dialog" aria-label="Share link: Create Savepoints"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">START TRANSACTION; -- Create first account CREATE (:Account {id: 4, name: 'David', balance: 1500}); SAVEPOINT sp1; -- Create second account CREATE (:Account {id: 5, name: 'Emma', balance: 2000}); SAVEPOINT sp2; -- Create third account CREATE (:Account {id: 6, name: 'Frank', balance: 500}); -- Rollback to sp2 (Frank not created) ROLLBACK TO SAVEPOINT sp2; -- Rollback to sp1 (Emma also not created) ROLLBACK TO SAVEPOINT sp1; -- Commit (only David created) COMMIT; -- Verify MATCH (a:Account) WHERE a.id IN [4, 5, 6] RETURN a.name; </code></pre></div>Expected output: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback">name ------ David </code></pre></div> <h4 id="multi-step-operation" class="position-relative d-flex align-items-center group"> Multi-Step Operation <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-step-operation" aria-haspopup="dialog" aria-label="Share link: Multi-Step Operation"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">START TRANSACTION; -- Step 1: Create user CREATE (:User {id: 'u1', name: 'John Doe', email: 'john@example.com'}); SAVEPOINT user_created; -- Step 2: Create preferences CREATE (:Preferences {user_id: 'u1', theme: 'dark', notifications: true}); SAVEPOINT prefs_created; -- Step 3: Create profile (fails validation) CREATE (:Profile {user_id: 'u1', bio: 'This bio is way too long and exceeds the 280 character limit...'}); -- Oops, bio too long - rollback profile only ROLLBACK TO SAVEPOINT prefs_created; -- Create valid profile CREATE (:Profile {user_id: 'u1', bio: 'Software developer'}); -- Commit all COMMIT; </code></pre></div> <h4 id="what-you-learned-1" class="position-relative d-flex align-items-center group"> What You Learned <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="what-you-learned-1" aria-haspopup="dialog" aria-label="Share link: What You Learned"> Share link </button> </h4><ul> <li><code>SAVEPOINT name</code> creates a checkpoint</li> <li><code>ROLLBACK TO SAVEPOINT name</code> undoes to that point</li> <li>Earlier savepoints remain valid</li> <li>Useful for complex multi-step operations</li> </ul> <h3 id="step-4-isolation-levels" class="position-relative d-flex align-items-center group"> Step 4: 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="step-4-isolation-levels" aria-haspopup="dialog" aria-label="Share link: Step 4: Isolation Levels"> Share link </button> </h3> <h4 id="read-committed-default" class="position-relative d-flex align-items-center group"> Read Committed (Default) <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-committed-default" aria-haspopup="dialog" aria-label="Share link: Read Committed (Default)"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Transaction 1 START TRANSACTION WITH ISOLATION LEVEL READ COMMITTED; MATCH (a:Account {name: 'Alice'}) RETURN a.balance; -- Returns 900 -- (Transaction 2 commits change: balance = 800) MATCH (a:Account {name: 'Alice'}) RETURN a.balance; -- Returns 800 (sees committed change) COMMIT; </code></pre></div>Behavior: Sees other transactions’ committed changes during execution. <h4 id="repeatable-read" class="position-relative d-flex align-items-center group"> Repeatable Read <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="repeatable-read" aria-haspopup="dialog" aria-label="Share link: Repeatable Read"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Transaction 1 START TRANSACTION WITH ISOLATION LEVEL REPEATABLE READ; MATCH (a:Account {name: 'Alice'}) RETURN a.balance; -- Returns 900 -- (Transaction 2 commits change: balance = 800) MATCH (a:Account {name: 'Alice'}) RETURN a.balance; -- Still returns 900 (repeatable read) COMMIT; </code></pre></div>Behavior: Sees consistent snapshot throughout transaction. <h4 id="serializable" class="position-relative d-flex align-items-center group"> Serializable <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="serializable" aria-haspopup="dialog" aria-label="Share link: Serializable"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Transaction 1 START TRANSACTION WITH ISOLATION LEVEL SERIALIZABLE; -- Read accounts in range MATCH (a:Account) WHERE a.balance > 500 RETURN count(a); -- Returns 2 -- (Transaction 2 tries to insert Account with balance=600) -- Blocked until Transaction 1 completes (prevents phantom reads) COMMIT; </code></pre></div>Behavior: Prevents phantom reads, full serializability. <h4 id="isolation-level-comparison" class="position-relative d-flex align-items-center group"> Isolation Level Comparison <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="isolation-level-comparison" aria-haspopup="dialog" aria-label="Share link: Isolation Level Comparison"> Share link </button> </h4><table> <thead> <tr> <th>Level</th> <th>Dirty Read</th> <th>Non-Repeatable Read</th> <th>Phantom Read</th> <th>Performance</th> </tr> </thead> <tbody> <tr> <td>Read Uncommitted</td> <td>❌ Possible</td> <td>❌ Possible</td> <td>❌ Possible</td> <td>Fastest</td> </tr> <tr> <td>Read Committed</td> <td>✅ Prevented</td> <td>❌ Possible</td> <td>❌ Possible</td> <td>Fast</td> </tr> <tr> <td>Repeatable Read</td> <td>✅ Prevented</td> <td>✅ Prevented</td> <td>❌ Possible</td> <td>Medium</td> </tr> <tr> <td>Serializable</td> <td>✅ Prevented</td> <td>✅ Prevented</td> <td>✅ Prevented</td> <td>Slowest</td> </tr> </tbody> </table> <h4 id="choosing-isolation-level" class="position-relative d-flex align-items-center group"> Choosing Isolation Level <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-isolation-level" aria-haspopup="dialog" aria-label="Share link: Choosing Isolation Level"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-python" data-lang="python"># Python client - Set isolation level from geode_client import Client client = Client(host="localhost", port=3141) async def transfer_with_isolation(conn, from_acc, to_acc, amount): """Transfer using the server's default isolation level.""" await conn.begin() try: page, _ = await conn.query(""" MATCH (from:Account {name: $from}) RETURN from.balance AS balance """, {'from': from_acc}) balance = page.rows[0]["balance"].raw_value if page.rows else 0 if balance < amount: raise ValueError("Insufficient funds") await conn.query(""" MATCH (from:Account {name: $from}) SET from.balance = from.balance - $amount """, {'from': from_acc, 'amount': amount}) await conn.query(""" MATCH (to:Account {name: $to}) SET to.balance = to.balance + $amount """, {'to': to_acc, 'amount': amount}) await conn.commit() except Exception: await conn.rollback() raise # async with client.connection() as conn: # await transfer_with_isolation(conn, "Alice", "Bob", 100) </code></pre></div> <h3 id="step-5-concurrent-updates" class="position-relative d-flex align-items-center group"> Step 5: Concurrent Updates <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="step-5-concurrent-updates" aria-haspopup="dialog" aria-label="Share link: Step 5: Concurrent Updates"> Share link </button> </h3> <h4 id="lost-update-problem" class="position-relative d-flex align-items-center group"> Lost Update Problem <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="lost-update-problem" aria-haspopup="dialog" aria-label="Share link: Lost Update Problem"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Transaction 1 (T1) START TRANSACTION; MATCH (a:Account {name: 'Alice'}) SET a.balance = a.balance + 100; -- Reads 900, sets 1000 -- Transaction 2 (T2) - runs concurrently START TRANSACTION; MATCH (a:Account {name: 'Alice'}) SET a.balance = a.balance + 50; -- Reads 900, sets 950 -- T1 commits: balance = 1000 COMMIT; -- (T1) -- T2 commits: balance = 950 (overwrites T1's update!) COMMIT; -- (T2) -- Lost update! Should be 1050 </code></pre></div> <h4 id="solution-use-serializable" class="position-relative d-flex align-items-center group"> Solution: Use SERIALIZABLE <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="solution-use-serializable" aria-haspopup="dialog" aria-label="Share link: Solution: Use SERIALIZABLE"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Transaction 1 START TRANSACTION WITH ISOLATION LEVEL SERIALIZABLE; MATCH (a:Account {name: 'Alice'}) SET a.balance = a.balance + 100; COMMIT; -- Transaction 2 (blocks until T1 commits) START TRANSACTION WITH ISOLATION LEVEL SERIALIZABLE; MATCH (a:Account {name: 'Alice'}) SET a.balance = a.balance + 50; -- Reads committed value from T1 COMMIT; -- Correct: balance updated by both transactions </code></pre></div> <h4 id="optimistic-locking-pattern" class="position-relative d-flex align-items-center group"> Optimistic Locking Pattern <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="optimistic-locking-pattern" aria-haspopup="dialog" aria-label="Share link: Optimistic Locking Pattern"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Read with version MATCH (a:Account {name: 'Alice'}) RETURN a.balance, a.version; -- Update with version check START TRANSACTION; MATCH (a:Account {name: 'Alice'}) WHERE a.version = $expected_version SET a.balance = a.balance + 100, a.version = a.version + 1; COMMIT; -- If no rows updated, version changed (concurrent update detected) </code></pre></div> <h3 id="step-6-deadlock-handling" class="position-relative d-flex align-items-center group"> Step 6: Deadlock Handling <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="step-6-deadlock-handling" aria-haspopup="dialog" aria-label="Share link: Step 6: Deadlock Handling"> Share link </button> </h3> <h4 id="deadlock-scenario" class="position-relative d-flex align-items-center group"> Deadlock Scenario <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="deadlock-scenario" aria-haspopup="dialog" aria-label="Share link: Deadlock Scenario"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Transaction 1 START TRANSACTION; MATCH (alice:Account {name: 'Alice'}) SET alice.balance = alice.balance - 50; -- Transaction 2 (concurrent) START TRANSACTION; MATCH (bob:Account {name: 'Bob'}) SET bob.balance = bob.balance - 50; -- Transaction 1 (waits for Bob) MATCH (bob:Account {name: 'Bob'}) SET bob.balance = bob.balance + 50; -- Transaction 2 (waits for Alice) - DEADLOCK! MATCH (alice:Account {name: 'Alice'}) SET alice.balance = alice.balance + 50; -- One transaction aborted automatically </code></pre></div> <h4 id="deadlock-prevention---lock-ordering" class="position-relative d-flex align-items-center group"> Deadlock Prevention - Lock Ordering <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="deadlock-prevention---lock-ordering" aria-haspopup="dialog" aria-label="Share link: Deadlock Prevention - Lock Ordering"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Always acquire locks in consistent order (e.g., alphabetically) -- Transaction 1 START TRANSACTION; -- Lock Alice first, then Bob (alphabetical order) MATCH (alice:Account {name: 'Alice'}) SET alice.balance = alice.balance - 50; MATCH (bob:Account {name: 'Bob'}) SET bob.balance = bob.balance + 50; COMMIT; -- Transaction 2 START TRANSACTION; -- Also lock Alice first, then Bob (same order!) MATCH (alice:Account {name: 'Alice'}) SET alice.balance = alice.balance + 25; MATCH (bob:Account {name: 'Bob'}) SET bob.balance = bob.balance - 25; COMMIT; -- No deadlock - consistent lock ordering </code></pre></div> <h4 id="retry-logic" class="position-relative d-flex align-items-center group"> Retry Logic <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="retry-logic" aria-haspopup="dialog" aria-label="Share link: Retry Logic"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-python" data-lang="python"># Python client - Retry on deadlock import time from geode_client import Client, QueryError client = Client(host="localhost", port=3141) async def transfer_with_retry(conn, from_acc, to_acc, amount, max_retries=3): """Transfer with deadlock retry logic""" for attempt in range(max_retries): try: await conn.begin() # Sort accounts to ensure consistent lock order accounts = sorted([from_acc, to_acc]) # Acquire locks in consistent order for account in accounts: await conn.query(""" MATCH (a:Account {name: $name}) RETURN a.balance """, {'name': account}) # Perform transfer await conn.query(""" MATCH (from:Account {name: $from}) SET from.balance = from.balance - $amount """, {'from': from_acc, 'amount': amount}) await conn.query(""" MATCH (to:Account {name: $to}) SET to.balance = to.balance + $amount """, {'to': to_acc, 'amount': amount}) await conn.commit() return # Success except QueryError as e: await conn.rollback() if 'deadlock' in str(e).lower(): if attempt < max_retries - 1: # Exponential backoff wait_time = (2 ** attempt) * 0.1 time.sleep(wait_time) print(f"Deadlock detected, retrying (attempt {attempt + 2})...") continue raise # Re-raise if not deadlock or max retries exceeded # Usage # async with client.connection() as conn: # await transfer_with_retry(conn, "Alice", "Bob", 100) </code></pre></div> <h3 id="step-7-common-transaction-patterns" class="position-relative d-flex align-items-center group"> Step 7: Common Transaction Patterns <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="step-7-common-transaction-patterns" aria-haspopup="dialog" aria-label="Share link: Step 7: Common Transaction Patterns"> Share link </button> </h3> <h4 id="batch-insert-with-rollback" class="position-relative d-flex align-items-center group"> Batch Insert with Rollback <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="batch-insert-with-rollback" aria-haspopup="dialog" aria-label="Share link: Batch Insert with Rollback"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">START TRANSACTION; -- Insert batch UNWIND range(1, 1000) AS i CREATE (:Product {id: i, name: 'Product ' + i, price: i * 10}); -- Verify count MATCH (p:Product) WITH count(p) AS product_count WHERE product_count < 1000 CALL { ROLLBACK; RETURN 'Rolled back - insufficient products' AS status } -- Otherwise commit COMMIT; </code></pre></div> <h4 id="audit-trail-pattern" class="position-relative d-flex align-items-center group"> Audit Trail Pattern <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="audit-trail-pattern" aria-haspopup="dialog" aria-label="Share link: Audit Trail Pattern"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">START TRANSACTION; -- Make change MATCH (a:Account {name: 'Alice'}) SET a.balance = a.balance - 500; -- Record audit log CREATE (:AuditLog { timestamp: timestamp(), account: 'Alice', operation: 'withdrawal', amount: 500, new_balance: a.balance }); COMMIT; </code></pre></div> <h4 id="cascading-deletes" class="position-relative d-flex align-items-center group"> Cascading Deletes <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="cascading-deletes" aria-haspopup="dialog" aria-label="Share link: Cascading Deletes"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">START TRANSACTION; -- Delete user MATCH (u:User {id: 'u1'}) DELETE u; -- Delete related data MATCH (pref:Preferences {user_id: 'u1'}) DELETE pref; MATCH (prof:Profile {user_id: 'u1'}) DELETE prof; MATCH (post:Post)-[:AUTHORED_BY]->(:User {id: 'u1'}) DETACH DELETE post; COMMIT; </code></pre></div> <h4 id="conditional-update" class="position-relative d-flex align-items-center group"> Conditional Update <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="conditional-update" aria-haspopup="dialog" aria-label="Share link: Conditional Update"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">START TRANSACTION; -- Update if condition met MATCH (a:Account {name: 'Alice'}) WHERE a.balance >= 1000 SET a.status = 'premium', a.discount_rate = 0.1; -- Create notification if updated MATCH (a:Account {name: 'Alice'}) WHERE a.status = 'premium' CREATE (:Notification { user: a.name, message: 'Congratulations! You are now a premium member', timestamp: timestamp() }); COMMIT; </code></pre></div> <h3 id="step-8-performance-considerations" class="position-relative d-flex align-items-center group"> Step 8: Performance 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="step-8-performance-considerations" aria-haspopup="dialog" aria-label="Share link: Step 8: Performance Considerations"> Share link </button> </h3> <h4 id="keep-transactions-short" class="position-relative d-flex align-items-center group"> Keep Transactions Short <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="keep-transactions-short" aria-haspopup="dialog" aria-label="Share link: Keep Transactions Short"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Bad: Long-running transaction START TRANSACTION; MATCH (p:Product) WHERE p.category = 'Electronics' WITH collect(p) AS products -- Processing takes 30 seconds... UNWIND products AS p SET p.processed = true; COMMIT; -- Holds locks for 30+ seconds! -- Good: Shorter transactions MATCH (p:Product) WHERE p.category = 'Electronics' RETURN collect(p.id) AS product_ids; -- Process in application layer -- Quick update transaction START TRANSACTION; UNWIND $product_ids AS id MATCH (p:Product {id: id}) SET p.processed = true; COMMIT; </code></pre></div> <h4 id="batch-operations" class="position-relative d-flex align-items-center group"> Batch Operations <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="batch-operations" aria-haspopup="dialog" aria-label="Share link: Batch Operations"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-python" data-lang="python"># Python client - Batch updates from geode_client import Client client = Client(host="localhost", port=3141) async def batch_update(conn, product_ids, batch_size=100): """Update products in batches""" for i in range(0, len(product_ids), batch_size): batch = product_ids[i:i + batch_size] await conn.begin() try: await conn.query(""" UNWIND $ids AS id MATCH (p:Product {id: id}) SET p.processed = true """, {'ids': batch}) await conn.commit() except Exception: await conn.rollback() raise # Process 10,000 products in batches of 100 # async with client.connection() as conn: # await batch_update(conn, product_ids, batch_size=100) </code></pre></div> <h3 id="complete-example-e-commerce-order-processing" class="position-relative d-flex align-items-center group"> Complete Example: E-Commerce Order Processing <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="complete-example-e-commerce-order-processing" aria-haspopup="dialog" aria-label="Share link: Complete Example: E-Commerce Order Processing"> Share link </button> </h3><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">START TRANSACTION WITH ISOLATION LEVEL SERIALIZABLE; -- Create order CREATE (order:Order { id: 'ord_12345', customer: 'Alice', total: 0, status: 'pending', created: timestamp() }); SAVEPOINT order_created; -- Add order items UNWIND [ {product_id: 'p1', quantity: 2, price: 50}, {product_id: 'p2', quantity: 1, price: 100} ] AS item MATCH (order:Order {id: 'ord_12345'}) MATCH (product:Product {id: item.product_id}) WHERE product.stock >= item.quantity CREATE (order)-[:CONTAINS { quantity: item.quantity, price: item.price }]->(product) SET product.stock = product.stock - item.quantity; SAVEPOINT items_added; -- Check all items added MATCH (order:Order {id: 'ord_12345'})-[c:CONTAINS]->() WITH order, sum(c.quantity * c.price) AS calculated_total WHERE calculated_total > 0 SET order.total = calculated_total, order.status = 'confirmed'; -- Create shipment MATCH (order:Order {id: 'ord_12345'}) WHERE order.status = 'confirmed' CREATE (:Shipment { order_id: order.id, status: 'preparing', created: timestamp() }); COMMIT; -- Verify MATCH (order:Order {id: 'ord_12345'}) OPTIONAL MATCH (order)-[c:CONTAINS]->(product:Product) OPTIONAL MATCH (ship:Shipment {order_id: order.id}) RETURN order.status, order.total, collect({product: product.name, quantity: c.quantity}) AS items, ship.status AS shipment_status; </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="transaction-already-active" class="position-relative d-flex align-items-center group"> Transaction Already Active <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-already-active" aria-haspopup="dialog" aria-label="Share link: Transaction Already Active"> Share link </button> </h4>Problem: Error when starting transaction Solution: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Rollback previous transaction ROLLBACK; -- Then start new one START TRANSACTION; </code></pre></div> <h4 id="no-active-transaction" class="position-relative d-flex align-items-center group"> No Active Transaction <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="no-active-transaction" aria-haspopup="dialog" aria-label="Share link: No Active Transaction"> Share link </button> </h4>Problem: COMMIT or ROLLBACK without START TRANSACTION Solution: <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Always start transaction first START TRANSACTION; -- ... operations ... COMMIT; </code></pre></div> <h4 id="deadlock-detected" class="position-relative d-flex align-items-center group"> Deadlock Detected <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="deadlock-detected" aria-haspopup="dialog" aria-label="Share link: Deadlock Detected"> Share link </button> </h4>Problem: Transactions waiting on each other Solutions: <ul> <li>Use consistent lock ordering</li> <li>Implement retry logic with exponential backoff</li> <li>Keep transactions short</li> <li>Consider lower isolation level</li> </ul> <h3 id="next-steps" class="position-relative d-flex align-items-center group"> Next Steps <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="next-steps" aria-haspopup="dialog" aria-label="Share link: Next Steps"> Share link </button> </h3><ul> <li><a href="/docs/transactions/advanced-patterns/" >Advanced Transaction Patterns</a> - Complex transaction scenarios</li> <li><a href="/docs/performance/" >Performance Tuning</a> - Optimize transaction performance</li> <li><a href="/docs/analytics/real-time-analytics/" >Real-Time Analytics</a> - Streaming with transactions</li> <li><a href="/docs/gql/guide/" >GQL Guide</a> - Complete transaction syntax</li> </ul> <h3 id="quick-reference" class="position-relative d-flex align-items-center group"> Quick Reference <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="quick-reference" aria-haspopup="dialog" aria-label="Share link: Quick Reference"> Share link </button> </h3> <h4 id="transaction-commands" class="position-relative d-flex align-items-center group"> Transaction Commands <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-commands" aria-haspopup="dialog" aria-label="Share link: Transaction Commands"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">-- Start transaction START TRANSACTION; START TRANSACTION WITH ISOLATION LEVEL SERIALIZABLE; -- Savepoints SAVEPOINT savepoint_name; ROLLBACK TO SAVEPOINT savepoint_name; RELEASE SAVEPOINT savepoint_name; -- Commit/Rollback COMMIT; ROLLBACK; </code></pre></div> <h4 id="isolation-levels" class="position-relative d-flex align-items-center group"> 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="isolation-levels" aria-haspopup="dialog" aria-label="Share link: Isolation Levels"> Share link </button> </h4><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-gql" data-lang="gql">READ UNCOMMITTED -- Lowest isolation, highest concurrency READ COMMITTED -- Default, prevents dirty reads REPEATABLE READ -- Prevents non-repeatable reads SERIALIZABLE -- Highest isolation, lowest concurrency </code></pre></div> <h4 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> </h4><ul> <li>✅ Keep transactions short</li> <li>✅ Use appropriate isolation level</li> <li>✅ Handle deadlocks with retry logic</li> <li>✅ Use savepoints for complex operations</li> <li>✅ Always commit or rollback</li> <li>❌ Don’t hold transactions during user input</li> <li>❌ Don’t perform expensive operations in transactions</li> <li>❌ Don’t ignore deadlock errors</li> </ul> <hr> Tutorial Complete! You now understand ACID transactions and isolation levels in Geode. Next: <a href="/docs/tutorials/graph-algorithms-tutorial/" >Graph Algorithms Tutorial</a>