The performance of Qlik Replicate is most critically impacted by network latency between the Replicate server and the source database. The Change Data Capture (CDC) process requires continuous and rapid reading of the source system's transaction logs. To ensure the highest efficiency and minimize delays in capturing data changes, the Replicate server must have the lowest possible latency to the source. Placing it on the same local area network (LAN) as the source database is the standard best practice. While the connection to the target is also important, applying batched changes is generally less sensitive to latency than the initial log-reading and capture process.

A. Placing Replicate near the target introduces high latency to the source, which severely degrades the performance of the transaction log reading process.

B. A "middle" location is a poor compromise, as it introduces unnecessary network latency to the most critical connection (the source).

D. For an on-premises source, a cloud installation introduces significant WAN latency, which is the primary factor to be avoided for the CDC process.

1. Qlik Replicate for Windows Installation and Setup Guide: In the "Deployment considerations" section, the guide explicitly states: "The Replicate machine should be located as close as possible to the source database (i.e. on the same LAN) to minimize latency." (Qlik Replicate November 2023, Installation and Setup Guide, Page 11).

2. Qlik Replicate User Guide: The "Architectural Overview" describes how Qlik Replicate reads change data directly from the source endpoint's transaction logs. This log-based CDC mechanism is highly sensitive to network round-trip time, reinforcing the need for close proximity to the source to maintain performance and low replication latency. (Qlik Replicate November 2023, User Guide, Chapter: "Getting Started", Section: "Architectural Overview").