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Posted to dev@age.apache.org by "AyoubKaz07 (via GitHub)" <gi...@apache.org> on 2026/06/29 19:47:58 UTC
[I] load_labels_from_file and load_edges_from_file functions undocumented use of comma as delimiter via PostgreSQL COPY default, causes data corruption on labels and segfault on edges [age]
AyoubKaz07 opened a new issue, #2449:
URL: https://github.com/apache/age/issues/2449
**Describe the bug**
Both functions rely on Postgres's COPY command, `ag_load_labels.c` and `ag_load_edges.c` share an identical `create_copy_options()` that only passes two options to `BeginCopyFrom` (header and format, everything else is default from Postgres).
`load_labels_from_file` with a pipe-delimited multi-column label CSV file silently corrupts data (correctly since default is comma). The entire line is read as a single field, column names get merged with values into one token, and the result lands in properties as garbage with no error:
```pgsql
id | properties
----------+---------------------------------------------
... | {"__id__": 1, "id|islocatedin_city": "1|5"}
```
`load_edges_from_file` with a pipe-delimited file crashes the server. The 4-column edge format requires `start_id, start_vertex_type, end_id, end_vertex_type` as separate fields. A quick lookup on it shows that with no comma splitting, fields[1] through fields[3] are null, `process_edge_row` calls `trim_whitespace(fields[1])` on a bad pointer, and the server segfaults.
The documentation mentions no delimiter requirement. The example files use comma but this is never stated as a constraint. The header row is handled manually in the loop rather than by COPY itself `(HEADER false)`, so the parsing feels custom, which makes it even less obvious that COPY's delimiter default is silently in effect underneath.
**How are you accessing AGE (Command line, driver, etc.)?**
- psql
**What is the command that caused the error?**
```pgsql
SELECT load_labels_from_file('graph', 'Label', '/derived/Label.csv'); -- No error, just incorrect parsing.
SELECT load_edges_from_file('graph', 'SomeEdge', '/derived/SomeEdge.csv'); -- This segfaults
```
```
026-06-29 19:25:56.972 GMT [1] LOG: client backend (PID 64) was terminated by signal 11: Segmentation fault
2026-06-29 19:25:56.972 GMT [1] DETAIL: Failed process was running: SELECT load_edges_from_file('graph', 'SomeEdge', '/derived/SomeEdge.csv');
2026-06-29 19:25:56.972 GMT [1] LOG: terminating any other active server processes
```
**Expected behavior**
Depends really, either have a delimiter option just like postgres COPY command options or clarify in documentation + correct error if comma only (instead of segfaulting).
**Environment (please complete the following information):**
- apache/age docker image.
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Re: [I] load_labels_from_file and load_edges_from_file functions undocumented use of comma as delimiter via PostgreSQL COPY default, causes data corruption on labels and segfault on edges [age]
Posted by "gregfelice (via GitHub)" <gi...@apache.org>.
gregfelice commented on issue #2449:
URL: https://github.com/apache/age/issues/2449#issuecomment-4875637832
Thanks for the thorough report and root-cause analysis, @AyoubKaz07 — this is valid, and the segfault makes it a must-fix.
Confirming on current `master`:
- `create_copy_options()` in both `ag_load_labels.c` and `ag_load_edges.c` still passes only `format` + `header` to `BeginCopyFrom`, so COPY's default comma delimiter is silently in effect — hence the silent corruption on pipe-delimited label files.
- `process_edge_row()` accesses `fields[0]`..`fields[3]` with no check against `nfields`, so a row that parses into fewer fields (e.g. a pipe-delimited line read as one comma field) dereferences a bad pointer at `trim_whitespace(fields[1])` and crashes the backend. #2453 recently added the `nfields` parameter and hardened malformed-row handling, but this particular access path isn't guarded yet, so the crash still reproduces.
Direction for a fix (all three are worth doing):
1. **Guard `process_edge_row` (and the label path) on `nfields`/column count** — turn the short-row crash into a clear `ereport(ERROR, ...)`. A reproducible segfault should never be reachable from user input.
2. **Add a `delimiter` option** to `create_copy_options()`, mirroring PostgreSQL COPY, plumbed through `load_labels_from_file` / `load_edges_from_file` so non-comma files are supported explicitly.
3. **Document the delimiter** requirement/option on the load functions.
Your analysis already pinpoints the code — if you'd like to open a PR we'd be glad to review; otherwise this is on the list. Either way, thanks for catching it.
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Re: [I] load_labels_from_file and load_edges_from_file functions undocumented use of comma as delimiter via PostgreSQL COPY default, causes data corruption on labels and segfault on edges [age]
Posted by "MuhammadTahaNaveed (via GitHub)" <gi...@apache.org>.
MuhammadTahaNaveed closed issue #2449: load_labels_from_file and load_edges_from_file functions undocumented use of comma as delimiter via PostgreSQL COPY default, causes data corruption on labels and segfault on edges
URL: https://github.com/apache/age/issues/2449
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