How we achieve sub-45ms real-time replication with log-based CDC

For modern enterprise architectures, the days of batch-processing data updates overnight are officially over. Whether you are feeding an on-premise data lake, keeping a distributed cloud cache warm, or syncing transactional records to an analytical warehouse, businesses now demand real-time data availability.

However, achieving real-time synchronization without degrading the performance of your production core systems is a massive engineering challenge.

Many traditional integration tools rely on invasive, high-overhead strategies like database triggers or continuous SQL polling. With Gluesync, we took a different path. By engineering our engine around Log-Based Change Data Capture (CDC), Gluesync intercepts and replicates data modifications in under 45 milliseconds, with near-zero impact on your source database workloads.

Here is an inside look at how we achieve this level of performance and how it protects your production environment.

The problem with legacy integration: triggers and polling

Before diving into log-based mechanics, it’s crucial to understand why traditional methods fail at scale:

• Query polling (SQL-based): this approach continuously fires SELECT queries (e.g., checking for WHERE last_updated > timestamp) against the production tables. As database sizes grow, these repeating table scans consume massive CPU and memory resources, causing application slowdowns.
• Database triggers: triggers execute custom code inside the database engine every time an INSERT, UPDATE, or DELETE occurs. This forces the transaction to wait until the trigger finishes, artificially increasing application latency and threatening core database stability.

Both methods force your production database to do double the work just to share its data.

Inside log-based CDC: reading the database’s “black box”

Every enterprise-grade relational database (such as Oracle, IBM Db2, Microsoft SQL Server, or PostgreSQL) maintains an internal, append-only file known as the Transaction Log (or Redo Log, Write-Ahead Log/WAL).

This log is the database’s ultimate source of truth. Before any data modification is written to a physical table or committed to storage, the database engine writes the exact sequential operation to this transaction log for crash-recovery purposes.

Gluesync does not query your tables. Instead, our CDC agents attach directly to this transaction log stream at the storage level.

1. Non-invasive interception: Gluesync reads the raw binary log data asynchronously. Because it bypasses the SQL execution layer entirely, the production application never experiences a drop in query performance.
2. Parsing raw mutations: Gluesync engine decodes the binary log entries in memory, reconstructing the exact transaction sequence (INSERT, UPDATE, DELETE) along with pre-and-post-image states of the affected rows.
3. Sub-45ms delivery: these parsed mutations are instantly structured into lightweight, optimized replication payloads and streamed down the pipeline directly to your target architecture, whether it is an on-premise share via our Universal File Store Agent, or a high-performance NoSQL cluster.

Why log-based CDC is a must for enterprise workloads

1. Absolute zero query overhead

Because Gluesync reads files that the database is already writing anyway, transaction log consumption happens in isolation. Your main application threads continue running at 100% capacity, oblivious to the fact that real-time replication is happening in the background.

2. Capture of true deletes and intermediate states

If an application updates a row three times within a single second, query polling will only capture the final state during its next scan. Even worse, if a row is deleted, polling can’t find it because it no longer exists. Gluesync’s log-based CDC captures every single state change, including the exact transaction boundaries and physical DELETE records.

3. Guaranteed data lineage and order

Transaction logs are strictly sequential. Gluesync processes changes in the exact historical order they occurred at the source. This prevents race conditions and data corruption at the target layer. A vital requirement for financial ledger or inventory synchronization.

Secure, governance-ready streaming

Reading transaction logs requires advanced security handling. Gluesync integrates directly with native enterprise log management APIs (such as Oracle LogMiner or PostgreSQL Replication Slots). Furthermore, all pipeline streams are strictly aligned with enterprise role-based access control (RBAC), ensuring that log data is decrypted, mapped and filtered according to strict security protocols before it ever moves across the wire.

Ready to modernize your data infrastructure?

Log-based CDC is the gold standard for real-time data integration, combining ultra-low replication latency with bulletproof production stability. By embedding this capability into a no-code, centralized control plane, Gluesync enables organizations to deploy resilient real-time pipelines in minutes instead of months.

Ready to eliminate replication latency without risking production bottlenecks? Skip the theoretical reading and benchmark Gluesync’s log-based CDC directly against your sandbox environments.

Request Your Free 30-Day here.