Review Marketplace apps causing blocked threads

This recommendation appears when we detect degraded page load performance that may be linked to one or more Marketplace apps. This can happen when app threads are repeatedly blocked, and one thread is waiting for another to finish using a shared resource. When many threads are waiting, pages may load more slowly for users. This is grouped as a blocked thread event, and the recommendation identifies the blocked app and displays the number of blocked threads, giving you a clear picture of where the blocked event originates.

Signals used

For us to detect this issue, the following conditions need to occur together:

• At least one of the key experiences shows degraded ready-for-user (RFU) page load times.

• Ten or more threads in a Marketplace app are identified in a BLOCKED state.

Filters

When the issue occurs multiple times, we group their signals under different filters, for example, Last 24 hours or Last 7 days. In this case:

• In the Degraded experiences section of the recommendation, we show the highest degradation from all occurrences.

• In the Apps with blocked threads section, we list the Marketplace apps whose threads are blocked. For each Marketplace app, we show the maximum number of concurrent blocked threads.

Frequency

Similar to filters, the Frequency section shows occurrences of this issue over time. It can help you spot patterns, for example, threads being blocked during peak usage hours, after scheduled jobs run, or along with the same apps.

Recommended actions

We recommend that you review and investigate the identified apps. The process to solve this issue will depend on the Marketplace app and what it does. Here are some actions you can take:

Review the blocked Marketplace app and the app blocking it (if different)

The recommendation may show two Marketplace apps: one whose threads are blocked (waiting) and another blocking it (in the RUNNING state). It is also possible that the blockage is caused by the app. The app causing the blockage is typically where the contention originates. Look for long-running transactions, synchronized methods, or database operations that may be causing blockages for an extended period.

To view a full breakdown of every affected app, select Download CSV. The CSV file provides detailed data that supports this recommendation, including different operation types. More about operation types

Look for patterns that align with blocked thread spikes

Identify whether high blocked thread counts coincide with specific user actions, scheduled tasks, synchronization jobs, indexing, reporting, automation rules, or traffic peaks. This can help determine whether the app is causing constant lock contention or only under certain conditions.

Review app configuration to reduce lock contention

Where possible, tune the app configuration to reduce lock duration. You can do so by lowering job frequency, disabling non-essential synchronized features, or moving heavy tasks away from peak usage periods. Additionally, if possible, you can try to temporarily disable the app causing the blockage to check if the issue is resolved.

If issues persist, contact the app vendor

If performance issues continue, contact the app vendor. Share that you're seeing high blocked thread counts. Mention the affected time window, the blocked and running plugin keys, and any recent configuration or usage changes so they can help identify opportunities to optimize or fix the issue.