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hrFLDNullKey
Where the workflow stopped
For hrFLDNullKey, the hexadecimal HRESULT is most useful when kept beside the API call and the affected artifact. The decisive boundary is key construction produced a NULL key for the current record or index expression.
The stored Value is 0x88000192 (positive JET status 402; 402). The HRESULT carries a warning, so the call may have useful output or a valid cursor state that must be inspected. The legacy this result name comes from the Windows Directory Service backup/restore message header.
The first useful distinction is that NULL is a data state, not the same condition as an empty string, zero-length binary value, or missing record. Start by capture the indexed columns, null flags, conditional-index rules, and the API result that consumed the key. That separates a reproducible incident from a later generic cleanup or service error.
Similar-looking outcomes
This result specifically means that NULL is a data state, not the same condition as an empty string, zero-length binary value, or missing record. Related values below can appear in the same workflow but require a different response:
hrFLDKeyTooBig | an index key exceeded the legacy key budget and was truncated rather than represented in full |
|---|---|
hrBadLogVersion | the transaction log format is incompatible with the ESE version attempting to read it |
hrMakeBackupDirectoryFail | ESE could not create the temporary directory required by the backup workflow |
Keep the original constant and hexadecimal value in telemetry. Replacing this result with “backup failed” or “database warning” removes the state information needed to select the next legal API call.
Objects and state involved
| Diagnostic layer | index key construction, NULL semantics, and legacy key limits |
|---|---|
| Relevant API surface | index definition, key creation, seeks, ranges, and record updates that change indexed values |
| Code-specific boundary | key construction produced a NULL key for the current record or index expression |
| Narrow corrective direction | handle the NULL-key branch explicitly and align index predicates with the application data model |
An index key is derived data whose byte representation depends on schema, locale, and column values., a warning can leave a usable cursor or index entry while changing exact-match or uniqueness assumptions.
Minimum useful trace
Preserve the first result before retries, cleanup, service restart, or file replacement changes the evidence. The diagnostic record should identify the exact API phase and the owner of every handle or artifact involved.
- Code-specific observation: capture the indexed columns, null flags, conditional-index rules, and the API result that consumed the key.
- Index definition and segment order: record it together with this result and the timestamp of the first occurrence.
- Normalized key length and bytes: record it together with it and the timestamp of the first occurrence.
- NULL and conditional-index rules: record it together with it and the timestamp of the first occurrence.
- Seek or insert result: record it together with it and the timestamp of the first occurrence.
Use hashes, lengths, IDs, generation numbers, and redacted samples instead of copying directory contents or sensitive database values into routine logs. For this it investigation, a complete provenance chain is often more useful than a second automatic retry.
Steps to resolve it
- Record it,
0x88000192, the API name, the current phase, and all live context or file owners. - Verify the decisive condition by capture the indexed columns, null flags, conditional-index rules, and the API result that consumed the key.
- Apply only the narrow correction: handle the NULL-key branch explicitly and align index predicates with the application data model.
- After it, recreate any context invalidated by the failure; do not carry stale HBC, cursor, file, or restore-map state into the retry.
- repeat the smallest non-destructive test that reaches the same boundary, then verify both the return value and the resulting file, cursor, backup, or database state.
Actions that can make diagnosis worse
- do not compare only the source text when the stored key is normalized or truncated.
- do not collapse NULL and empty values in diagnostics.
- do not discard the first lower-level Win32, RPC, or JET result merely because a later cleanup call returned a more familiar error.
Acceptance criteria for a fix
A useful regression test for this HRESULT should force the condition “key construction produced a NULL key for the current record or index expression”, call one documented API transition, and assert the exact HRESULT. The corrected the case should change only the decisive precondition and should verify cleanup as well as the primary output. For the result backup or restore path, also prove that the resulting set can be enumerated and that no file handle or context remains active after finalization.
Technical references
- ESE warnings and errors — API ordering, file semantics, warning/error interpretation, or recovery behavior relevant to it.
- JET_ERR enumeration
- Open-source ESE implementation
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