Убрать из плана seq scan : PostgreSQL

 WITH user AS (
                SELECT DISTINCT UNNEST(ARRAY['27672','6145']) AS "Id"
          ),
          ar AS(
                SELECT
                "@Id" AS "Id",
                  array_remove("User", user."Id") AS "NewUser",
                CASE
                      WHEN array_length(array_remove("User", user."Id"), 1) > 0 THEN FALSE
                      ELSE TRUE
                END AS "NeedDelete"
                FROM "Documents" ar, user
                WHERE
                      "Account" = 4777912 AND
                      array_position(ar."User", user."Id") IS NOT NULL
          ),
          delete_ar AS(
                DELETE FROM "Documents"
                USING ar
                WHERE "@Id" = ar."Id" AND
                      ar."NeedDelete" IS TRUE
          )
          UPDATE "Documents"
          SET "User" = ar."NewUser"
          FROM ar
          WHERE ar."Id" = "@Id" AND
               ar."NeedDelete" IS FALSE 

Update on "Documents"  (cost=19771027.17..22312135.48 rows=2074177 width=134) (actual time=188992.755..188992.755 rows=0 loops=1)
  Buffers: shared hit=22742 read=2790563 dirtied=121272 written=56091, temp read=8246 written=1402207
  CTE user
    ->  HashAggregate  (cost=0.02..0.52 rows=100 width=32) (actual time=0.007..0.010 rows=2 loops=1)
          Group Key: unnest('{27672,6145}'::text[])
          ->  Result  (cost=0.00..0.01 rows=1 width=32) (actual time=0.003..0.004 rows=2 loops=1)
  CTE ar
    ->  Nested Loop  (cost=0.57..237640.03 rows=4148354 width=37) (actual time=59.829..484.828 rows=44 loops=1)
          Join Filter: (array_position(ar_1."User", user."Id") IS NOT NULL)
          Rows Removed by Join Filter: 24234
          Buffers: shared hit=7660 read=1433 dirtied=13
          ->  CTE Scan on user  (cost=0.00..2.00 rows=100 width=32) (actual time=0.008..0.015 rows=2 loops=1)
          ->  Materialize  (cost=0.57..133720.72 rows=41692 width=35) (actual time=0.649..236.659 rows=12139 loops=2)
                Buffers: shared hit=7660 read=1433 dirtied=13
                ->  Index Scan using "iDocuments-AccountDocument" on "Documents" ar_1  (cost=0.57..133512.26 rows=41692 width=35) (actual time=1.296..466.032 rows=12139 loops=1)
                      Index Cond: ("Account" = '4777912'::bigint)
                      Buffers: shared hit=7660 read=1433 dirtied=13
  CTE delete_ar
    ->  Delete on "Documents" "Documents_1"  (cost=8512344.15..10206749.46 rows=2074177 width=34) (actual time=148112.808..148112.808 rows=0 loops=1)
          Buffers: shared hit=3422 read=2800776 dirtied=29, temp read=59703 written=801388
          ->  Hash Join  (cost=8512344.15..10206749.46 rows=2074177 width=34) (actual time=143942.901..148111.006 rows=38 loops=1)
                Hash Cond: (ar_2."Id" = "Documents_1"."@Id")
                Buffers: shared hit=3388 read=2800772 dirtied=3, temp read=59703 written=801388
                ->  CTE Scan on ar ar_2  (cost=0.00..82967.08 rows=2074177 width=32) (actual time=0.030..0.104 rows=38 loops=1)
                      Filter: ("NeedDelete" IS TRUE)
                      Rows Removed by Filter: 6
                ->  Hash  (cost=4888739.29..4888739.29 rows=208459029 width=10) (actual time=143820.738..143820.738 rows=205483044 loops=1)
                      Buckets: 1048576  Batches: 512  Memory Usage: 25459kB
                      Buffers: shared hit=3388 read=2800772 dirtied=3, temp written=800839
                      ->  Seq Scan on "Documents" "Documents_1"  (cost=0.00..4888739.29 rows=208459029 width=10) (actual time=0.040..85509.087 rows=205483044 loops=1)
                            Buffers: shared hit=3388 read=2800772 dirtied=3
  ->  Hash Join  (cost=9326637.15..11867745.46 rows=2074177 width=134) (actual time=187388.784..188988.878 rows=6 loops=1)
        Hash Cond: (ar."Id" = "Documents"."@Id")
        Buffers: shared hit=22689 read=2790553 dirtied=121259 written=56091, temp read=8246 written=1402207
        ->  CTE Scan on ar  (cost=0.00..82967.08 rows=2074177 width=96) (actual time=297.173..484.991 rows=6 loops=1)
              Filter: ("NeedDelete" IS FALSE)
              Rows Removed by Filter: 38
              Buffers: shared hit=7660 read=1433 dirtied=13
        ->  Hash  (cost=4888739.29..4888739.29 rows=208459029 width=42) (actual time=186809.680..186809.680 rows=205483044 loops=1)
              Buckets: 524288  Batches: 1024  Memory Usage: 17420kB
              Buffers: shared hit=15029 read=2789120 dirtied=121246 written=56091, temp written=1401178
              ->  Seq Scan on "Documents"  (cost=0.00..4888739.29 rows=208459029 width=42) (actual time=0.712..100785.196 rows=205483044 loops=1)
                    Buffers: shared hit=15029 read=2789120 dirtied=121246 written=56091