Query on a single-attribute key schema applies a condition on a non-key attribute to the sort key #674

Activity

1. LeeroyHannigan commented on Nov 1, 2026

   

   LeeroyHannigan

   on Nov 1, 2026

   CollaboratorAuthor

   More actions

   Measured on the service on 1 November 2026 at about 13:18 UTC, on a table keyed on pk (S) with no RANGE attribute, two samples each:

   request	answer
   pk = :p AND ssn = :s	400 ValidationException: The number of query conditions (2) exceeds the number of key attributes defined in the schema (1)
   pk = :p AND #s = :s, #s = ssn	the same

   So on a table with no RANGE attribute the condition count rule answers. A SQLite build with main's Query code answered the first request with 200 and the item whose ssn matched.
2. LeeroyHannigan commented on Nov 10, 2026

   

   LeeroyHannigan

   on Nov 10, 2026

   CollaboratorAuthor

   More actions

   Measured on the service on 10 November 2026 in us-east-1, two sends each. The service answers every shape below with 400 ValidationException.

   main at e681b8b, SQLite backend, dev build, replayed with the same expressions and values. Each shape got two sends, plus one send whose values make the second clause false. Table A has the key pk (S), a GSI with the key g (S), and the items p1 (x v1, y w1, g v1), p2 (x v2, y w2, g v1) and p3 (g v3). Table B has the key pk (S), sk (S) and the items (p1, s1, x v1), (p1, s2, x v2) and (p1, v1, x zz).

   table key	KeyConditionExpression	service	main at e681b8b, SQLite
   pk	pk = :p AND #n = :v AND #m = :w, #n = x, #m = y, :p p1, :v v1, :w w1	The number of query conditions (3) exceeds the number of key attributes defined in the schema (1)	200, no item, while p1 has x v1 and y w1
   pk	pk = :p AND begins_with(#n, :v), #n = x, :p p1, :v v	The number of query conditions (2) exceeds the number of key attributes defined in the schema (1)	200, item p1; with :p p3, item p3, which has no x
   pk, GSI on g	pk = :p AND #g = :v, #g = g, :p p1, :v v1, sent to the table	the same message with (2) and (1)	200, item p1; with :p p3, item p3, whose g is v3
   pk, sk	pk = :p AND sk = :s AND #n = :v, #n = x, :p p1, :s s1, :v v1	The number of query conditions (3) exceeds the number of key attributes defined in the schema (2)	200, no item, while (p1, s1) has x v1
   pk, sk	pk = :p AND #n = :v, #n = x, :p p1, :v v1	Query condition missed key schema element: sk	200, the item whose sk is v1 (x zz); with :v s2, the item whose sk is s2

   Rows 1 and 4 are conditions with three clauses on a single-attribute key schema. The last row is the base table form with an equality. The description of this issue lists these shapes as not measured on the service.

   The code path on main. On a key schema with one HASH and at most one RANGE attribute, handle_query makes one check on the parsed condition. The clause the parser took as the partition key must name the HASH attribute (crates/engine/src/query.rs lines 329 to 336). Nothing checks the other clauses. With three or more clauses, classify_multi takes the first equality as the partition key clause and the last clause as the sort key condition. The equalities between them go to extra_pk_conditions (crates/core/src/expression/key_condition.rs lines 716 to 765). resolve_key_schema_with reclassifies those on a multi-attribute key schema only (lines 399 to 424). On these tables they reach storage. The SQLite backend encodes the partition key value and every extra_pk_conditions value as one composite key text (crates/storage-sqlite/src/data/query_scan.rs lines 55 to 63). No row of a table with one HASH attribute has that key. That is why the two three-clause shapes return no item. A sort key condition that names no RANGE attribute applies to the first RANGE column (lines 90 to 92). A table with no RANGE attribute has no such column, so the two-clause shapes on A return the partition's item whatever the second clause says. The PostgreSQL backend builds the key and the sort key condition the same way (crates/storage-postgres/src/data/query_scan.rs lines 147 to 158 and 190 to 192). This replay used SQLite only.

   Expected: the condition count message. On a table with one key attribute, a KeyConditionExpression with two or more clauses answers it with the clause count and (1). Three clauses on a table with two key attributes answer it with (3) and (2). pk = :p AND #n = :v on a table with a RANGE attribute answers Query condition missed key schema element: sk. Each answer comes before the request reaches storage.