query issue

Hi,

I have postgres 10 running on RDS instance.

I have query below:

select * from "op_KFDaBAZDSXc4YYts9"."UserFeedItems"
where (("itemType" not in ('WELCOME_POST', 'UPLOAD_CONTACTS',
'BROADCAST_POST')) and ("userId" = '5d230d67bd99c5001b1ae757' and
"is_deleted" in (true, false)))
order by "score" asc, "updatedAt" desc limit 10;

Explain plan is like given below:

QUERY PLAN
Limit (cost=11058.03..11058.05 rows=10 width=1304) (actual
time=6105.283..6105.293 rows=10 loops=1)
-> Sort (cost=11058.03..11065.36 rows=2935 width=1304) (actual
time=6105.281..6105.283 rows=10 loops=1)
Sort Key: score, "updatedAt" DESC
Sort Method: top-N heapsort Memory: 36kB
-> Bitmap Heap Scan on "UserFeedItems"
(cost=131.33..10994.60 rows=2935 width=1304) (actual
time=26.245..6093.680 rows=3882 loops=1)
Recheck Cond: ("userId" = '5d230d67bd99c5001b1ae757'::text)
Filter: ((is_deleted = ANY ('{t,f}'::boolean[])) AND
("itemType" <> ALL
('{WELCOME_POST,UPLOAD_CONTACTS,BROADCAST_POST}'::text[])))
Rows Removed by Filter: 1
Heap Blocks: exact=3804
-> Bitmap Index Scan on "userId" (cost=0.00..130.60
rows=2956 width=0) (actual time=24.835..24.836 rows=3885 loops=1)
Index Cond: ("userId" = '5d230d67bd99c5001b1ae757'::text)
Planning time: 20.928 ms
Execution time: 6108.610 ms

My table structure is somewhat like this

CREATE TABLE "op_KFDaBAZDSXc4YYts9"."UserFeedItems"
(
_id text COLLATE pg_catalog."default" NOT NULL DEFAULT uuid_generate_v4(),
"userId" text COLLATE pg_catalog."default" NOT NULL,
"itemType" text COLLATE pg_catalog."default" NOT NULL,
payload jsonb NOT NULL,
score numeric NOT NULL,
"generalFeedItemId" text COLLATE pg_catalog."default",
"createdAt" timestamp without time zone NOT NULL DEFAULT
(now())::timestamp without time zone,
"createdBy" text COLLATE pg_catalog."default",
"updatedAt" timestamp without time zone NOT NULL DEFAULT
(now())::timestamp without time zone,
"updatedBy" text COLLATE pg_catalog."default",
is_deleted boolean DEFAULT false,
"isRead" boolean NOT NULL DEFAULT false,
CONSTRAINT "UserFeedItems_pkey" PRIMARY KEY (_id)
)
WITH (
OIDS = FALSE
)
TABLESPACE pg_default;

CREATE INDEX "UserFeedItems_id"
ON "op_KFDaBAZDSXc4YYts9"."UserFeedItems" USING btree
(_id COLLATE pg_catalog."default" ASC NULLS LAST)
TABLESPACE pg_default;
-- Index: UserFeedItems_itemType_userId_isdeleted_score_updatedAt

-- DROP INDEX "op_KFDaBAZDSXc4YYts9"."UserFeedItems_itemType_userId_isdeleted_score_updatedAt";

CREATE INDEX "UserFeedItems_itemType_userId_isdeleted_score_updatedAt"
ON "op_KFDaBAZDSXc4YYts9"."UserFeedItems" USING btree
("itemType" COLLATE pg_catalog."default" ASC NULLS LAST, "userId"
COLLATE pg_catalog."default" ASC NULLS LAST, is_deleted ASC NULLS
LAST, score ASC NULLS LAST, "updatedAt" DESC NULLS FIRST)
TABLESPACE pg_default;
-- Index: score

-- DROP INDEX "op_KFDaBAZDSXc4YYts9".score;

CREATE INDEX score
ON "op_KFDaBAZDSXc4YYts9"."UserFeedItems" USING btree
(score ASC NULLS LAST)
TABLESPACE pg_default;
-- Index: updatedat

-- DROP INDEX "op_KFDaBAZDSXc4YYts9".updatedat;

CREATE INDEX updatedat
ON "op_KFDaBAZDSXc4YYts9"."UserFeedItems" USING btree
("updatedAt" DESC NULLS FIRST)
TABLESPACE pg_default;
-- Index: userId

-- DROP INDEX "op_KFDaBAZDSXc4YYts9"."userId";

CREATE INDEX "userId"
ON "op_KFDaBAZDSXc4YYts9"."UserFeedItems" USING btree
("userId" COLLATE pg_catalog."default" text_pattern_ops ASC NULLS LAST)
TABLESPACE pg_default;

So my doubt is initially when I run this query it takes around 42
seconds to complete but later after few minutes it completes in 2-3
seconds.

I tried to create indexes on table for columns score & "updatedAt"
DESC seperately but found no proper satisfied solution.

So please help me telling what I am exactly missing here ?

Regards,
Atul