Error: why is the GSI dynamodb not showing item count

A GSI's ItemCount from DescribeTable is an approximate statistic updated about every six hours. A stale or zero count does not by itself mean the index has lost items.

1. Check IndexStatus and Backfilling. A newly created index must finish building before it is ready for queries.
2. Query a known index key to verify data visibility. GSIs are eventually consistent, so a recent write may not appear immediately.
3. Check sparse-index membership: an item missing a required index key is not included. A GSI count need not equal its table count.
4. For a current count, use Query with Select: COUNT for a known partition, or Scan with IndexName and Select: COUNT for the whole index, and sum Count across every page.

Counting reads index data and consumes capacity. COUNT saves response payload, not read work, and multiple pages are not a consistent snapshot while writes continue. Waiting for the metadata refresh is the inexpensive option when an approximate count is enough.

See GSI operation and AWS documentation.