Exchange SE BigFunnel Search indexing issue – FastDocumentTimeoutException and RetryFeeder backlog

Question

Exchange SE BigFunnel Search indexing issue – FastDocumentTimeoutException and RetryFeeder backlog

OZ 291

Hello Microsoft Support,

We are experiencing a persistent Exchange Server Subscription Edition search/indexing issue on build 15.2.2562.49.

Affected server example:

EX19-[Moderator note: Personally Identifiable Information removed]

DAG environment

HostControllerService and MSExchangeFastSearch are Running

Multiple noderunner.exe processes are active

Main symptoms:

Outlook/OWA search is incomplete for some mailboxes

Many mailboxes have non-zero BigFunnelNotIndexedCount

BigFunnelRetryFeederTimeBasedAssistant develops a large backlog

PeriodicJob shows many mailboxes in Pending and one mailbox can remain in Running for a long time

Start-MailboxAssistant -AssistantName BigFunnelRetryFeederTimeBasedAssistant does not clear the backlog

Restarting MSExchangeMailboxAssistants did not resolve the issue

Moving an affected mailbox to another database appears to restore indexing/search for that mailbox

We see repeated Event ID 9042 from MSExchange Assistants for multiple databases:

BigFunnel Retry Feeder Time Based Assistant ... is exiting a work cycle.

No mailboxes were successfully processed.

3 mailboxes were skipped due to errors.

0 mailboxes were retried.

The most significant issue is in Exchange Search logs:

Microsoft.Exchange.Search.Fast.FastDocumentTimeoutException:

The Content Submission Service returned failure for the document:

The operation has timed out.

Stack path:

BigFunnel.OnSaveFeeder.FlowFeeder.ProcessMessage

BigFunnel.OnSaveFeeder.ContentIndexingConnection.ProcessMessage

BigFunnel.OnSaveFeeder.PoiCreatorClient.CreatePoi

The errors occur in both:

...\Logging\Search\OnSaveContentIndexingConnection

...\Logging\Search\RetryContentIndexingConnection

We counted approximately 43,000+ FastDocumentTimeoutException events within 24 hours, affecting multiple mailbox/database GUIDs.

Example affected mailbox:

Alias: [Moderator note: Personally Identifiable Information removed]

ExchangeGuid: [Moderator note: Personally Identifiable Information removed]

Database: MDB-[Moderator note: Personally Identifiable Information removed]

BigFunnelNotIndexedCount: 2327

Another affected mailbox:

Alias: sudarkina.e

ExchangeGuid: [Moderator note: Personally Identifiable Information removed]

We also captured RetryFeeder thread stacks showing workers reaching FlowFeeder.ProcessMessage / PoiCreatorClient.CreatePoi, which suggests the bottleneck may be in the Search/BigFunnel/Ceres content submission pipeline.

Please advise:

Whether this matches a known Exchange SE Search/BigFunnel issue

Whether build 15.2.2562.49 has a known defect related to Content Submission / BigFunnel

Whether a hotfix or future update is planned

Whether there is a supported per-mailbox BigFunnel reset/rebuild method without moving the mailbox

Which diagnostics/logs you would like us to collect

We can provide Search logs, RetryFeeder logs, Event 9042 entries, Get-ExchangeDiagnosticInfo output, thread stacks, and BigFunnel statistics.

Rachel N 0 Reputation points

2026-09-29T13:57:16.9866667+00:00

Hello OZ,

We are running into the exact same problem since we upgraded to SE build 15.2.2562.49 a few weeks ago. This is impacting search on thousands of mailboxes, and the BigFunnelNotIndexedCount number are climbing. Where you able to remediate or get input from Microsoft support on a solution?

1 answer

Your answer

Rachel N 0 Reputation points

2026-09-29T13:57:16.9866667+00:00

Hello OZ,

We are running into the exact same problem since we upgraded to SE build 15.2.2562.49 a few weeks ago. This is impacting search on thousands of mailboxes, and the BigFunnelNotIndexedCount number are climbing. Where you able to remediate or get input from Microsoft support on a solution?

Answer 1

Hi @OZ

For now, I was only able to find the Microsoft article Incomplete search results after installing an Exchange Server 2019 update, which describes a similar scenario where mailbox items enter a permanent failure state and are no longer retried automatically by BigFunnel indexing. The documented guidance includes using the BigFunnel retry assistant together with a temporary BigFunnel setting override to reprocess affected items.

However, this article specifically applies to Exchange Server 2019. While the New-SettingOverride cmdlet is available in on-premises Exchange, including Exchange Server SE, I was unable to find Microsoft documentation explicitly confirming that the BigFunnel permanent retry guidance described in the article also applies to Exchange Server Subscription Edition. Therefore, I cannot confirm what impact this approach may have in your specific Exchange Server SE environment.

Additionally, I was unable to locate any Microsoft documentation, release notes, or known issue announcements confirming that this is a known Exchange Server SE Search/BigFunnel issue matching the reported symptoms, or a known defect in Exchange Server SE build 15.2.2562.49 related to Content Submission Service timeouts, FastDocumentTimeoutException, or the BigFunnel indexing pipeline.

Given the absence of publicly documented guidance for Exchange Server SE and the volume of FastDocumentTimeoutException events reported, I would recommend engaging Microsoft Support for further investigation. Exchange Server SE support is available through Microsoft Unified Support. You can create a support request through the Microsoft Engage Center. A support engineer can review the Search logs, BigFunnel statistics, Event ID 9042 entries, diagnostic output, and trace data, and, if necessary, involve the Exchange product group for deeper analysis.

Please note that this is a paid support channel and requires an active support agreement or applicable support entitlement. The advantage is that the case can be reviewed directly by the engineering teams responsible for Exchange Server SE when required.

Reference: Open a new Support request - Microsoft Engage Center | Microsoft Learn

If you have any additional findings or troubleshooting results regarding this issue, please feel free to share them here. They may help other community members who encounter similar behavior and contribute valuable knowledge to the community.