The Database Query That Confirmed a Deal Pipeline Bottleneck: Debugging CIDgravity Provider Availability in FGW

Message Overview

On February 4, 2026, during an intensive debugging session of the Filecoin Gateway (FGW) distributed storage system, an assistant executed a targeted database query to resolve a puzzling question: why was a group with 30GB of data ready for deals not initiating any deal proposals, despite the Lotus gateway being operational and the deal tracker loop completing successfully?

The message in question is a single bash command:

ssh 10.1.232.82 "/opt/yugabyte/bin/ysqlsh -h 10.1.232.82 -p 5433 -U yugabyte -d filecoingw_kuri_01 -c 'SELECT id, g_state FROM groups;'"

Which returned:

 id  | g_state 
-----+---------
   1 |       3
 101 |       0
(2 rows)

This seemingly simple query—two rows of integers—represented a critical diagnostic pivot in a multi-hour debugging session. It was the moment the assistant moved from observing symptoms through application logs to interrogating the system's ground truth: the database itself. The query confirmed that Group 1 was indeed in state 3 (GroupStateLocalReadyForDeals) and Group 101 was in state 0 (GroupStateWritable), matching what the application API had reported. This ruled out a data inconsistency between the application layer and the database, forcing the debugging focus deeper into the deal-making pipeline.

The Context: A Stalled Deal Pipeline

The message sits at a pivotal moment in a multi-hour debugging session focused on the Filecoin Gateway (FGW), a distributed storage system that provides an S3-compatible API backed by Filecoin decentralized storage. The system had been deployed across three physical nodes in a QA environment: a head node running YugabyteDB and an S3 proxy, plus two Kuri storage nodes (fgw-ribs1 and fgw-ribs2) that handle the actual storage and deal-making logic.

Earlier in the session, the team had resolved a critical infrastructure issue: the Lotus gateway (pac-l-gw.devtty.eu), which provides the Filecoin blockchain interface, had been down and was now restored. The assistant verified the gateway was operational by successfully retrieving the chain head at height 5,729,846. With the gateway back online, the expectation was that the deal pipeline would begin flowing—Group 1 had approximately 30GB of data in state 3 (GroupStateLocalReadyForDeals), meaning it was ready to initiate storage deals with Filecoin storage providers.

However, the deal tracker logs told a different story. The cleanup loop was completing successfully in 35–43 seconds (a marked improvement from the earlier 150-second timeouts), but no GBAP (Get Best Available Providers) calls were being made, no deal proposals were being initiated, and the group remained stubbornly empty of deals. The assistant's initial investigation through application logs revealed a concerning silence: the makeMoreDeals function, which is the entry point for initiating new storage deals, was apparently never being called.

The Reasoning Behind the Query

The assistant's thinking process, visible through the sequence of commands leading up to message 2319, reveals a methodical debugging approach. The first hypothesis was that the application's GetGroupDealStats() function might be returning stale or inconsistent data—perhaps the database had a different state than what the API reported. This is a common class of bug in distributed systems where caching layers, eventual consistency models, or partial write failures can cause the application layer to diverge from the database ground truth.

The assistant had already verified through the RIBS API that Group 1 had state 3, and had traced through the code to confirm that state 3 maps to GroupStateLocalReadyForDeals (defined via Go's iota keyword in iface/iface_rbs.go, where GroupStateWritable = 0, GroupStateFull = 1, GroupStateVRCARDone = 2, and GroupStateLocalReadyForDeals = 3). But the API is served by the Kuri application itself—what if the application had a bug that caused it to misreport the state? The only way to be certain was to query the database directly.

The path to the successful query was itself instructive. The assistant first attempted to use psql on the head node (message 2315), but psql was not installed—the YugabyteDB distribution uses its own ysqlsh client. The next attempt (message 2316) used ysqlsh but connected to localhost, which failed because YugabyteDB was configured to listen on the node's external IP (10.1.232.82:5433), not on the loopback interface. A quick check with ss -tlnp (message 2318) confirmed this: the PostgreSQL-compatible process was listening on 10.1.232.82:5433, not 127.0.0.1:5433.

The Query and Its Result

The successful query in message 2319 used the correct host IP:

ssh 10.1.232.82 "/opt/yugabyte/bin/ysqlsh -h 10.1.232.82 -p 5433 -U yugabyte -d filecoingw_kuri_01 -c 'SELECT id, g_state FROM groups;'"

The result was concise but definitive:

 id  | g_state 
-----+---------
   1 |       3
 101 |       0
(2 rows)

Group 1 had g_state = 3 and Group 101 had g_state = 0. This matched exactly what the application API had reported. The database and the application were in agreement.

What This Ruled Out

This single query eliminated several possible root causes:

  1. Application-level caching bug: If the application had been caching stale state, the database would have shown a different value. It did not.
  2. Partial write or failed state transition: If the group's state transition from "full" to "ready for deals" had only partially persisted, the database might have shown an intermediate or inconsistent state. It did not.
  3. Data corruption in the groups table: The row was present, well-formed, and contained the expected integer value.
  4. Database connection issue: The Kuri application was successfully connecting to YugabyteDB and reading the correct data, ruling out a connectivity or authentication problem between the storage nodes and the database.

What It Did Not Rule Out

While the query confirmed the group state was correct, it also raised the stakes for the remaining investigation. If the data was correct and the application was reading it correctly, then the problem had to be in the logic that acts on that data—specifically, the conditions in runDealCheckCleanupLoop that determine whether to call makeMoreDeals.

The assistant's subsequent investigation (messages 2320–2330) reveals the next steps: running the full GetGroupDealStats query directly against the database to verify the join logic, adding info-level logging to trace the execution path, and ultimately discovering that makeMoreDeals was indeed being called but was failing silently because the GBAP call to CIDgravity returned zero providers. The root cause turned out to be a missing removeUnsealedCopy field in the GBAP request payload—a parameter that the CIDgravity API required but the application was not sending.

Assumptions and Knowledge Required

To understand this message, several pieces of context are necessary. The reader must know that the FGW system uses YugabyteDB as its metadata store, with a schema that includes a groups table tracking the state of each storage group through an integer-based state machine. The state values are defined in the Go source code using iota, meaning GroupStateLocalReadyForDeals = 3. The reader must also understand that the QA cluster has three physical nodes with specific IP addresses and roles, and that the YugabyteDB client (ysqlsh) must connect using the node's external IP rather than localhost because of the network configuration.

The assistant made a reasonable assumption that localhost would work for connecting to a locally-running database, which turned out to be incorrect—YugabyteDB was bound to the external interface only. This is a common operational nuance in database deployments where security policies or multi-homed network configurations affect binding behavior.

The Deeper Significance

At first glance, message 2319 appears to be a trivial database query—two rows of integers returned in under a second. But in the context of a complex distributed systems debugging session, it represents a critical decision point. The assistant chose to bypass the application layer entirely and interrogate the system's source of truth directly. This is a debugging technique that experienced engineers reach for when log analysis and API inspection have yielded ambiguous results. By confirming that the database state matched the application state, the assistant could confidently eliminate an entire class of potential bugs and focus on the more subtle issue of why the deal-making logic was not progressing despite correct input data.

The query also demonstrates the importance of understanding your infrastructure's connectivity patterns. The failed localhost connection and the subsequent ss -tlnp check to discover the correct binding address are small but significant operational learnings. In a distributed system with multiple services running on multiple nodes, knowing exactly how each service listens for connections is essential for effective debugging.

Conclusion

Message 2319 is a textbook example of a targeted diagnostic query in a distributed systems context. It is not the flashy moment where the bug is found and fixed—that comes later in the session when the missing removeUnsealedCopy field is identified. Instead, it is the quiet, methodical step where a hypothesis is tested and a class of potential causes is ruled out. The assistant's decision to query the database directly, the process of discovering the correct connection parameters, and the clean confirmation that the data was consistent all reflect a disciplined approach to debugging: start with the ground truth, verify your assumptions, and only then move on to the next layer of investigation.