Indexing Rules

The authoritative index architecture — the CDX logical container and the LMDB-backed order environment — is documented in CDX and LMDB Indexing. This page summarizes the rules that keep ordering deterministic and rebuilds stable.

Key expression and tags

• An index tag is built from a key expression over one or more fields (INDEX ON <expr> TAG <name>).
• A CDX container holds one or more named tags; SET ORDER TO <tag> selects the active logical order for navigation and SEEK.
• The logical order is served from the LMDB index environment, not by scanning and sorting the DBF.

Deterministic ordering

• Keys are normalized before comparison so the same input always sorts the same way (consistent collation and comparison rules).
• Duplicate keys are ordered stably; SEEK lands on the first matching record in the active direction (ASCEND / DESCEND).
• SEEK on the active tag uses an LMDB keyed range-seek (O(log n)), and the landed record is re-verified against the DBF before it is accepted.

Maintenance

• REINDEX is the canonical rebuild dispatcher (INX, CNX, CDX/LMDB, and student index families), choosing a default family by table flavor.
• BUILDLMDB builds or rebuilds the LMDB backing store for a CDX container.
• After a buffered COMMIT or crash recovery, an indexed table needs a REINDEX — COMMIT does not do incremental CDX/LMDB maintenance.

See also

• CDX and LMDB Indexing
• DotTalk++ Data Mutators
• ArcticTalk (TUI)