Amp-powered subgraphs: Add runtime endBlock completion check#6369
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Amp-powered subgraphs: Add runtime endBlock completion check#6369
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lutter
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Feb 16, 2026
Add a runtime check in run_indexing that detects when the Amp Flight server's latest block covers through every data source's endBlock, even when no entity data exists at the endBlock itself. Previously, the only completion check compared the persisted block pointer (which only advances when data is written) against endBlock, causing an infinite polling loop when endBlock has no data. The check compares latest_block (min MAX(_block_num) across non-completed tables) against max_end_block (max end_block across all data sources). If latest_block >= max_end_block, all SQL queries have been served and indexing completes.
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Summary
endBlock.Problem
The existing
indexing_completedcheck (at the top of the loop) relies on the persisted block pointer (latest_synced_block) having advanced toendBlock. However, ifendBlockitself contains no entity data, the store's block pointer is never advanced to that block number, and the subgraph never reports as synced – it loops indefinitely waiting for a block pointer that will never be written.Solution
After consuming the data stream in each iteration, check whether the Amp Flight server's
latest_blockalready covers throughmax_end_block(). If so, mark the deployment as synced and return, bypassing the need for the persisted block pointer to reachendBlockexactly. This is safe because the server's latest block confirms all queries throughendBlockhave been served.Future Improvements
This will be replaced by persistent completion (to avoid executing queries on restarts to confirm completion) once the Amp-based block cache or the Amp Admin API is integrated into the graph-node.