diff --git a/CHANGELOG.md b/CHANGELOG.md
index b439aa6e2..b9098d5dc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -72,6 +72,8 @@ Each entry that ships in a published release links to the PR that introduced it.
 - **The `eql_v2` schema and its entire surface are removed — EQL now ships only the self-contained `eql_v3` encrypted-domain surface.** Dropped with no `eql_v3` replacement: the `eql_v2_encrypted` composite column type and its operators (`=`, `<>`, `~~`/`~~*` `LIKE`/`ILIKE`, containment `@>`/`<@`, ORE comparisons), database-side configuration management (`eql_v2_configuration`, `add_search_config`, `add_column`, `migrate_config`, `diff_config`, `create_encrypted_columns`), the `encryptindex` migration machinery, boolean operators on the encrypted column type, operator-class-on-column indexing, and `GROUP BY` / `grouped_value` on the encrypted column type. Searchable-encryption capabilities (equality, ordered range, `MIN`/`MAX`, encrypted-JSONB document containment and path access) are all provided by the `eql_v3` encrypted-domain families and document surface. Why: `eql_v3` is now fully self-contained — it owns its own SEM index-term types (`eql_v3.hmac_256`, `eql_v3.ore_block_256`, `eql_v3.ore_cllw`, `eql_v3.bloom_filter`) and installs into a database with no `eql_v2` present — and the encryption client (CipherStash Proxy / ProtectJS) now owns the configuration model the database-side `eql_v2` functions previously provided. This is a major (3.0.0) public-API break; callers using the `eql_v2` schema migrate to the `eql_v3` encrypted-domain types. The user-facing reference documentation and tutorials have been migrated to teach only the `eql_v3` surface — the `eql_v2`-based examples, the database-side configuration guide, and the operator-class-on-column indexing recipe are removed. No per-capability migration guide is provided for the dropped capabilities (they have no `eql_v3` equivalent).
 ### Fixed
 
+- **`ore_block_256` opclass-path helpers converted from `LANGUAGE sql` to plpgsql — restores v2-level ordered-scan performance.** `eql_v3_internal.jsonb_array_to_bytea_array` and `eql_v3_internal.jsonb_array_to_ore_block_256` were `LANGUAGE sql` for inlineability, but their only caller chain (`ore_block_256(val)`, plpgsql, feeding the btree operator class) can never inline SQL functions — every compared value paid the per-call SQL-function executor instead, measured at 3.5× the per-call cost of the logic-identical plpgsql form. Release benchmarks put the end-to-end cost at +43% on ORE ordered index scans vs EQL 2.3 (`0.513 → 0.736 ms` at 1M rows) and +36% on the composite bloom+ORE-order shape (`16.6 → 22.7 ms`); with the plpgsql form both scenarios return to (or beat) the v2 numbers — `0.553 ms` and `13.97 ms` respectively, validated A→B→A on a live 1M-row bench database. Semantics are unchanged: NULL/non-array inputs still return NULL, and the empty-`ob` COALESCE (#262) is preserved. The `eql-inline-critical` markers are retained so the pin_search_path pass keeps both functions unpinned — a `SET search_path` clause on plpgsql forces per-call configuration switching in the same hot path. Full attribution and experiment data: cipherstash/benches#23 (`v3-regressions-report.md`). ([#353](https://github.com/cipherstash/encrypt-query-language/issues/353))
+
 - **`=` / `<>` on `eql_v2.ore_block_u64_8_256` now declare a `COMMUTATOR`, so equality joins over the ORE term no longer raise.** Both operators set `COMMUTATOR` to themselves (equality and inequality are symmetric, so each is its own commutator). Why: without it the planner raised `could not find commutator for operator` the first time an `ore_block_u64_8_256` equality was used as a join / mergejoin qualifier (e.g. via the inlined `eql_v3.integer_ord_ore` equality wrappers, since the operators carry `MERGES`). This only enables previously-erroring join plans — it cannot change which rows match or their ordering. ([#239](https://github.com/cipherstash/encrypt-query-language/pull/239))
 
 - **The `eql_v3` ORE block comparator now orders ciphertexts of any block count, not just 8.** `eql_v3.compare_ore_block_256_term` derives the block count `N` from the term length (`octet_length = 49·N + 16`) instead of hardcoding 8, so encrypted types whose native ORE width exceeds 8 blocks — `numeric` (14) and `timestamp` (12) — order, range-query, `ORDER BY`, and `MIN`/`MAX` correctly instead of silently mis-ordering. Malformed terms (length not `49·N + 16` for `N ≥ 1`) now raise instead of returning a bogus comparison. The self-contained `eql_v3` SEM type was renamed `eql_v3.ore_block_u64_8_256 → eql_v3.ore_block_256` to reflect that it is width-agnostic (the `eql_v2` type is unchanged). No effect on existing 8-block types (a no-op for `N = 8`). ([#241](https://github.com/cipherstash/encrypt-query-language/issues/241), [#276](https://github.com/cipherstash/encrypt-query-language/pull/276))
diff --git a/src/v3/common.sql b/src/v3/common.sql
index 8fe4da2ff..a81ea3724 100644
--- a/src/v3/common.sql
+++ b/src/v3/common.sql
@@ -18,32 +18,40 @@
 --!
 --! @note Returns NULL if input is JSON null
 --! @note Each array element is hex-decoded to bytea
---! @note Inlinable `LANGUAGE sql` IMMUTABLE form (no `SET search_path`) so the
---!   planner can fold this per-encrypted-value helper into the calling query.
---!   This deliberately diverges from the v2 plpgsql equivalent (intentionally
---!   left unchanged): the `CASE WHEN jsonb_typeof(val) = 'array'` guard only
---!   evaluates the set-returning `jsonb_array_elements_text` for an array, so a
---!   non-array JSON scalar returns NULL here instead of raising "cannot extract
---!   elements from a scalar". Both callers only ever pass an array or JSON null
---!   (`val->'ob'`), so the divergence is unreachable in practice; JSON null and
---!   empty array still return NULL exactly as before.
+--! @note plpgsql, not `LANGUAGE sql` (issue #353). This helper's ONLY caller
+--!   chain is `ore_block_256(val)` -> `jsonb_array_to_ore_block_256(val)` —
+--!   both reached exclusively from plpgsql and btree operator-class support
+--!   contexts, where SQL functions can NEVER be inlined and instead pay the
+--!   per-call SQL-function executor (measured 3.5x the per-call cost of the
+--!   plpgsql equivalent; +43% on ORE ordered scans end-to-end). plpgsql
+--!   caches its plan across calls. The non-array guard preserves the v3
+--!   behaviour (returns NULL for a non-array scalar; the v2 plpgsql original
+--!   raised) — both callers only ever pass an array or JSON null (`val->'ob'`),
+--!   so the divergence stays unreachable in practice; JSON null and empty
+--!   array still return NULL exactly as before.
 CREATE FUNCTION eql_v3_internal.jsonb_array_to_bytea_array(val jsonb)
 RETURNS bytea[]
   IMMUTABLE
 AS $$
-  SELECT CASE WHEN jsonb_typeof(val) = 'array'
-    THEN (
-      SELECT array_agg(decode(value::text, 'hex')::bytea)
-      FROM jsonb_array_elements_text(val) AS value
-    )
-    ELSE NULL
-  END;
-$$ LANGUAGE sql;
+DECLARE
+  result bytea[];
+BEGIN
+  IF val IS NULL OR jsonb_typeof(val) != 'array' THEN
+    RETURN NULL;
+  END IF;
+  SELECT array_agg(decode(value::text, 'hex')::bytea)
+    INTO result
+  FROM jsonb_array_elements_text(val) AS value;
+  RETURN result;
+END;
+$$ LANGUAGE plpgsql;
 
---! @internal Mark this hand-written helper inline-critical so the post-install
---! pin_search_path pass leaves it unpinned (no `SET search_path`), preserving
---! SQL-function inlining. It takes a bare `jsonb` arg (not a jsonb-backed
---! encrypted DOMAIN), so the structural skip in tasks/pin_search_path_v3.sql does
---! not recognise it; this marker is the documented manual opt-in.
+--! @internal Keep the inline-critical marker so the post-install
+--! pin_search_path pass leaves this unpinned: a `SET search_path` clause on a
+--! plpgsql function forces per-call configuration switching — measurable on a
+--! helper invoked per compared value in the ore_block_256 opclass hot path.
+--! It takes a bare `jsonb` arg (not a jsonb-backed encrypted DOMAIN), so the
+--! structural skip in tasks/pin_search_path_v3.sql does not recognise it;
+--! this marker is the documented manual opt-in.
 COMMENT ON FUNCTION eql_v3_internal.jsonb_array_to_bytea_array(jsonb) IS
-  'eql-inline-critical: per-encrypted-value ORE helper; must stay inlinable (unpinned search_path)';
+  'eql-inline-critical: per-encrypted-value ORE opclass-path helper; must stay unpinned (SET search_path adds per-call overhead)';
diff --git a/src/v3/sem/ore_block_256/functions.sql b/src/v3/sem/ore_block_256/functions.sql
index e4098ecc5..45f31fdce 100644
--- a/src/v3/sem/ore_block_256/functions.sql
+++ b/src/v3/sem/ore_block_256/functions.sql
@@ -17,14 +17,15 @@
 --! @internal
 --! @param val jsonb Array of hex-encoded ORE block terms
 --! @return eql_v3_internal.ore_block_256 ORE block composite, or NULL if input is null
---! @note Inlinable `LANGUAGE sql` IMMUTABLE form (no `SET search_path`) so the
---!   planner can fold this per-encrypted-value helper into the calling query.
---!   This deliberately diverges from the v2 plpgsql equivalent (intentionally
---!   left unchanged): the `CASE WHEN jsonb_typeof(val) = 'array'` guard only
---!   evaluates the array path for an array, so a non-array JSON scalar returns
---!   NULL here instead of raising. The sole caller (`ore_block_256`) only reaches
---!   this when `has_ore_block_256(val)` is true, which now requires `val->'ob'`
---!   to be a JSON array, so the non-array branch is unreachable in practice.
+--! @note plpgsql, not `LANGUAGE sql` (issue #353). The sole caller
+--!   (`ore_block_256`) is itself plpgsql, so this function is NEVER reached
+--!   from an inlinable context — as `LANGUAGE sql` it paid the per-call
+--!   SQL-function executor on every compared value in the opclass hot path
+--!   (measured: +43% on ORE ordered scans vs the plpgsql form). The
+--!   non-array guard preserves the v3 behaviour (returns NULL for a
+--!   non-array scalar; the v2 plpgsql original raised); the caller only
+--!   reaches this when `has_ore_block_256(val)` is true, which requires
+--!   `val->'ob'` to be a JSON array, so that branch stays unreachable.
 --!   An empty array (`ob: []`, what encrypting the empty string `""` produces)
 --!   yields a non-NULL composite with an EMPTY `terms` array — NOT NULL terms.
 --!   The `COALESCE` is load-bearing: `array_agg` over zero rows returns NULL, and
@@ -36,25 +37,33 @@ CREATE FUNCTION eql_v3_internal.jsonb_array_to_ore_block_256(val jsonb)
 RETURNS eql_v3_internal.ore_block_256
   IMMUTABLE
 AS $$
-  SELECT CASE WHEN jsonb_typeof(val) = 'array'
-    THEN ROW(COALESCE(
-      (
-        SELECT array_agg(ROW(b)::eql_v3_internal.ore_block_256_term)
-        FROM unnest(eql_v3_internal.jsonb_array_to_bytea_array(val)) AS b
-      ),
-      ARRAY[]::eql_v3_internal.ore_block_256_term[]
-    ))::eql_v3_internal.ore_block_256
-    ELSE NULL
-  END;
-$$ LANGUAGE sql;
+DECLARE
+  terms eql_v3_internal.ore_block_256_term[];
+BEGIN
+  IF val IS NULL OR jsonb_typeof(val) != 'array' THEN
+    RETURN NULL;
+  END IF;
+  SELECT array_agg(ROW(b)::eql_v3_internal.ore_block_256_term)
+    INTO terms
+  FROM unnest(eql_v3_internal.jsonb_array_to_bytea_array(val)) AS b;
+  -- plpgsql pitfall: `SELECT <composite> INTO <composite-var>` assigns the
+  -- select-list columns FIELD-WISE into the variable — return the row
+  -- constructor directly instead. The COALESCE stays load-bearing for the
+  -- empty-`ob` case (issue #262): array_agg over zero rows yields NULL, and
+  -- the comparator needs an EMPTY terms array, not NULL terms.
+  RETURN ROW(COALESCE(terms, ARRAY[]::eql_v3_internal.ore_block_256_term[]))::eql_v3_internal.ore_block_256;
+END;
+$$ LANGUAGE plpgsql;
 
---! @internal Mark this hand-written helper inline-critical so the post-install
---! pin_search_path pass leaves it unpinned (no `SET search_path`), preserving
---! SQL-function inlining. It takes a bare `jsonb` arg (not a jsonb-backed
---! encrypted DOMAIN), so the structural skip in tasks/pin_search_path_v3.sql does
---! not recognise it; this marker is the documented manual opt-in.
+--! @internal Keep the inline-critical marker so the post-install
+--! pin_search_path pass leaves this unpinned: a `SET search_path` clause on a
+--! plpgsql function forces per-call configuration switching — measurable on a
+--! helper invoked per compared value in the ore_block_256 opclass hot path.
+--! It takes a bare `jsonb` arg (not a jsonb-backed encrypted DOMAIN), so the
+--! structural skip in tasks/pin_search_path_v3.sql does not recognise it;
+--! this marker is the documented manual opt-in.
 COMMENT ON FUNCTION eql_v3_internal.jsonb_array_to_ore_block_256(jsonb) IS
-  'eql-inline-critical: per-encrypted-value ORE helper; must stay inlinable (unpinned search_path)';
+  'eql-inline-critical: per-encrypted-value ORE opclass-path helper; must stay unpinned (SET search_path adds per-call overhead)';
 
 
 --! @brief Extract ORE block index term from JSONB payload
diff --git a/tests/sqlx/tests/encrypted_domain/family/inlinability.rs b/tests/sqlx/tests/encrypted_domain/family/inlinability.rs
index 2a9480edc..142c3a98e 100644
--- a/tests/sqlx/tests/encrypted_domain/family/inlinability.rs
+++ b/tests/sqlx/tests/encrypted_domain/family/inlinability.rs
@@ -96,23 +96,17 @@ async fn no_encrypted_domain_inline_critical_function_is_pinned(pool: PgPool) ->
 /// regresses to Seq Scan — this test fails instead.
 ///
 /// `jsonb_array_to_bytea_array(jsonb)` and
-/// `jsonb_array_to_ore_block_256(jsonb)` are included here: both take a
-/// bare `jsonb` arg (not a jsonb-backed encrypted DOMAIN), so the structural
-/// skip in tasks/pin_search_path_v3.sql does not recognise them — they are kept
-/// unpinned by the `eql-inline-critical` COMMENT marker instead. This test
-/// asserts the unpinned + inlinable-SQL state directly; the companion
-/// `eql_v3_sem_inline_critical_functions_carry_marker` test below asserts the
-/// marker itself, so an edit that drops the marker (or a pin_search_path_v3.sql
-/// refactor that stops honouring it) fails CI even though both checks live in
-/// separate tests.
+/// `jsonb_array_to_ore_block_256(jsonb)` are NOT in this test's inlinable-SQL
+/// set: their only caller chain (`ore_block_256(val)`, plpgsql, feeding the
+/// btree operator class) can never inline a SQL function, so they are plpgsql
+/// by design (issue #353) and guarded by the dedicated
+/// `eql_v3_ore_block_256_opclass_helpers_are_plpgsql_and_unpinned` test below.
 #[sqlx::test]
 async fn eql_v3_sem_inline_critical_functions_are_unpinned(pool: PgPool) -> Result<()> {
     let rows: Vec<(String,)> = sqlx::query_as(
         r#"
         WITH expected(proname, pronargs, arg0, arg1) AS (
           VALUES
-            ('jsonb_array_to_bytea_array', 1, 'jsonb'::regtype, 0::oid),
-            ('jsonb_array_to_ore_block_256', 1, 'jsonb'::regtype, 0::oid),
             ('ore_cllw', 1, 'jsonb'::regtype, 0::oid),
             ('has_ore_cllw', 1, 'jsonb'::regtype, 0::oid),
             ('meta_data', 1, 'jsonb'::regtype, 0::oid),
@@ -145,9 +139,7 @@ async fn eql_v3_sem_inline_critical_functions_are_unpinned(pool: PgPool) -> Resu
               'hmac_256',
               'bloom_filter',
               'ore_cllw',
-              'has_ore_cllw',
-              'jsonb_array_to_bytea_array',
-              'jsonb_array_to_ore_block_256')
+              'has_ore_cllw')
                 AND p.proargtypes[0] = 'jsonb'::regtype)
             OR e.proname IS NOT NULL
           )
@@ -171,17 +163,17 @@ async fn eql_v3_sem_inline_critical_functions_are_unpinned(pool: PgPool) -> Resu
     Ok(())
 }
 
-/// Companion guard for the two bare-`jsonb` per-encrypted-value helpers
-/// (`jsonb_array_to_bytea_array`, `jsonb_array_to_ore_block_256`). The
-/// unpinned state asserted above is only DURABLE because each helper carries an
-/// `eql-inline-critical` COMMENT marker that `tasks/pin_search_path_v3.sql` honours
-/// (it skips pinning functions whose `pg_description` matches
-/// `'eql-inline-critical%'`). Neither helper is caught by the structural
-/// jsonb-domain skip, so the marker is the ONLY thing keeping them unpinned —
-/// an edit that removes the marker, or a pin_search_path_v3.sql refactor that drops
-/// the marker handling, would silently re-pin them and break inlining. This test
-/// asserts the marker is present (and the helpers are SQL/IMMUTABLE) so that
-/// failure surfaces here.
+/// Companion guard: the unpinned state asserted above is only DURABLE for
+/// bare-`jsonb` helpers because each carries an `eql-inline-critical` COMMENT
+/// marker that `tasks/pin_search_path_v3.sql` honours (it skips pinning
+/// functions whose `pg_description` matches `'eql-inline-critical%'`). These
+/// helpers are not caught by the structural jsonb-domain skip, so the marker
+/// is the ONLY thing keeping them unpinned — an edit that removes the marker,
+/// or a pin_search_path_v3.sql refactor that drops the marker handling, would
+/// silently re-pin them and break inlining. This test asserts the marker is
+/// present (and the helpers are SQL/IMMUTABLE). The two plpgsql
+/// `jsonb_array_to_*` opclass-path helpers are guarded separately below
+/// (issue #353).
 #[sqlx::test]
 async fn eql_v3_sem_inline_critical_helpers_carry_marker(pool: PgPool) -> Result<()> {
     // Each expected helper must appear with a present inline-critical marker
@@ -191,8 +183,6 @@ async fn eql_v3_sem_inline_critical_helpers_carry_marker(pool: PgPool) -> Result
         r#"
         WITH expected(proname, pronargs, arg0, arg1) AS (
           VALUES
-            ('jsonb_array_to_bytea_array', 1, 'jsonb'::regtype, 0::oid),
-            ('jsonb_array_to_ore_block_256', 1, 'jsonb'::regtype, 0::oid),
             ('ore_cllw', 1, 'jsonb'::regtype, 0::oid),
             ('has_ore_cllw', 1, 'jsonb'::regtype, 0::oid),
             ('meta_data', 1, 'jsonb'::regtype, 0::oid),
@@ -238,6 +228,73 @@ async fn eql_v3_sem_inline_critical_helpers_carry_marker(pool: PgPool) -> Result
     Ok(())
 }
 
+/// Dedicated guard for the two `ore_block_256` opclass-path helpers
+/// (`jsonb_array_to_bytea_array`, `jsonb_array_to_ore_block_256`) — issue #353.
+///
+/// Their only caller chain is `ore_block_256(val)` (plpgsql) feeding the btree
+/// operator class: neither plpgsql callers nor opclass support contexts can
+/// EVER inline a SQL function, so as `LANGUAGE sql` these paid the per-call
+/// SQL-function executor on every compared value (measured 3.5x the plpgsql
+/// per-call cost; +43% end-to-end on ORE ordered index scans — see
+/// cipherstash/benches#23). They are therefore plpgsql BY DESIGN, and must
+/// stay: (a) plpgsql — a revert to LANGUAGE sql reintroduces the regression;
+/// (b) IMMUTABLE; (c) UNPINNED, via the `eql-inline-critical` marker — a
+/// `SET search_path` clause on plpgsql forces per-call configuration
+/// switching in the same hot path.
+#[sqlx::test]
+async fn eql_v3_ore_block_256_opclass_helpers_are_plpgsql_and_unpinned(pool: PgPool) -> Result<()> {
+    let offenders: Vec<(
+        String,
+        Option<String>,
+        Option<String>,
+        Option<String>,
+        Option<bool>,
+    )> = sqlx::query_as(
+        r#"
+        WITH expected(proname) AS (
+          VALUES ('jsonb_array_to_bytea_array'), ('jsonb_array_to_ore_block_256')
+        )
+        SELECT e.proname,
+               l.lanname::text,
+               p.provolatile::text,
+               d.description,
+               EXISTS (
+                 SELECT 1 FROM unnest(coalesce(p.proconfig, '{}'::text[])) c
+                 WHERE c LIKE 'search_path=%'
+               ) AS pinned
+        FROM expected e
+        LEFT JOIN pg_catalog.pg_proc p
+          ON p.proname = e.proname
+         AND p.pronamespace = 'eql_v3_internal'::regnamespace
+         AND p.pronargs = 1
+         AND p.proargtypes[0] = 'jsonb'::regtype
+        LEFT JOIN pg_catalog.pg_language l ON l.oid = p.prolang
+        LEFT JOIN pg_catalog.pg_description d
+          ON d.objoid = p.oid AND d.classoid = 'pg_proc'::regclass
+        WHERE p.oid IS NULL
+           OR l.lanname IS DISTINCT FROM 'plpgsql'
+           OR p.provolatile IS DISTINCT FROM 'i'
+           OR d.description IS NULL
+           OR d.description NOT LIKE 'eql-inline-critical%'
+           OR EXISTS (
+                 SELECT 1 FROM unnest(coalesce(p.proconfig, '{}'::text[])) c
+                 WHERE c LIKE 'search_path=%'
+              )
+        ORDER BY e.proname
+        "#,
+    )
+    .fetch_all(&pool)
+    .await?;
+
+    assert!(
+        offenders.is_empty(),
+        "ore_block_256 opclass-path helpers must be plpgsql + IMMUTABLE + \
+         marker-unpinned (issue #353) — offenders (proname, lang, volatility, \
+         marker, pinned): {offenders:#?}"
+    );
+    Ok(())
+}
+
 #[sqlx::test]
 async fn every_inline_critical_eligible_domain_has_inline_critical_functions(
     pool: PgPool,