JackieTien97 commented on code in PR #816:
URL: https://github.com/apache/tsfile/pull/816#discussion_r3251953344
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python/tsfile/dataset/reader.py:
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@@ -217,6 +227,111 @@ def _cache_metadata_table_model(self):
)
sys.stderr.flush()
+ def _cache_metadata_tree_model(self):
+ """Build the in-memory catalog by synthesizing one virtual table.
+
+ Tree TsFiles have no schema, so we materialize a single
+ ``TableEntry``: table name = the shared root segment, tag columns
+ = ``_col_1..._col_{N_max}`` (one per remaining path segment),
+ fields = union of measurements across devices. Per-device
+ ownership is preserved by registering only the
+ ``(device_id, field_idx)`` pairs actually written on disk in
+ ``series_stats_by_ref``.
+ """
+ metadata_groups = self._reader.get_timeseries_metadata(None)
+ if not metadata_groups:
+ raise ValueError("No devices found in tree-model TsFile")
+
+ # 1) Walk every device once to collect: root-segment, max depth, and
+ # the union of measurements that pass the numeric filter.
+ root_name = None
+ max_depth = 0 # segments after the root (i.e. virtual tag depth)
+ device_specs = [] # list of (tail_segments, group, stats_by_field)
+ union_fields = [] # ordered union of measurement names
+ seen_field_names = set()
+
+ for device_path, group in metadata_groups.items():
+ if not device_path:
+ continue
+ full_segments = tuple(device_path.split("."))
+ if not full_segments:
+ continue
+ current_root = full_segments[0]
+ if root_name is None:
+ root_name = current_root
Review Comment:
This validation rejects tree files with multiple root segments (`root_name
!= current_root`). In practice, IoTDB tree-model files virtually always use
`root` as the single root. However, the synthetic table uses the root segment
as the `table_name`, so if a file ever had devices under multiple roots, the
virtual table would be ambiguous.
The error message is clear and this is the right behavior — just noting that
I'd expect this to never actually fire in practice. If it does, it signals a
seriously malformed file rather than a normal use case.
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