Postgres query performance improvement - postgresql

Question

I am a newbie to database optimisations,
The table data I have is around 29 million rows,
I am running on Pgadmin to do select * on the rows and it takes 9 seconds.
What can I do to optimize performance?
SELECT
F."Id",
F."Name",
F."Url",
F."CountryModel",
F."RegionModel",
F."CityModel",
F."Street",
F."Phone",
F."PostCode",
F."Images",
F."Rank",
F."CommentCount",
F."PageRank",
F."Description",
F."Properties",
F."IsVerify",
count(*) AS Counter
FROM
public."Firms" F,
LATERAL unnest(F."Properties") AS P
WHERE
F."CountryId" = 1
AND F."RegionId" = 7
AND F."CityId" = 4365
AND P = ANY (ARRAY[126, 128])
AND F."Deleted" = FALSE
GROUP BY
F."Id"
ORDER BY
Counter DESC,
F."IsVerify" DESC,
F."PageRank" DESC OFFSET 10 ROWS FETCH FIRST 20 ROW ONLY
Thats my query plan
" -> Sort (cost=11945.20..11948.15 rows=1178 width=369) (actual time=8981.514..8981.515 rows=30 loops=1)"
" Sort Key: (count(*)) DESC, f.""IsVerify"" DESC, f.""PageRank"" DESC"
" Sort Method: top-N heapsort Memory: 58kB"
" -> HashAggregate (cost=11898.63..11910.41 rows=1178 width=369) (actual time=8981.234..8981.305 rows=309 loops=1)"
" Group Key: f.""Id"""
" Batches: 1 Memory Usage: 577kB"
" -> Nested Loop (cost=7050.07..11886.85 rows=2356 width=360) (actual time=79.408..8980.167 rows=322 loops=1)"
" -> Bitmap Heap Scan on ""Firms"" f (cost=7050.06..11716.04 rows=1178 width=360) (actual time=78.414..8909.649 rows=56071 loops=1)"
" Recheck Cond: ((""CityId"" = 4365) AND (""RegionId"" = 7))"
" Filter: ((NOT ""Deleted"") AND (""CountryId"" = 1))"
" Heap Blocks: exact=55330"
" -> BitmapAnd (cost=7050.06..7050.06 rows=1178 width=0) (actual time=70.947..70.947 rows=0 loops=1)"
" -> Bitmap Index Scan on ""IX_Firms_CityId"" (cost=0.00..635.62 rows=58025 width=0) (actual time=11.563..11.563 rows=56072 loops=1)"
" Index Cond: (""CityId"" = 4365)"
" -> Bitmap Index Scan on ""IX_Firms_RegionId"" (cost=0.00..6413.60 rows=588955 width=0) (actual time=57.795..57.795 rows=598278 loops=1)"
" Index Cond: (""RegionId"" = 7)"
" -> Function Scan on unnest p (cost=0.00..0.13 rows=2 width=0) (actual time=0.001..0.001 rows=0 loops=56071)"
" Filter: (p = ANY ('{126,128}'::integer[]))"
" Rows Removed by Filter: 2"
"Planning Time: 0.351 ms"
"Execution Time: 8981.725 ms"```

Answer 1

Create a GIN index on F."Properties",
create index on "Firms" using gin ("Properties");
then add a clause to your WHERE
...
AND P = ANY (ARRAY[126, 128])
AND "Properties" && ARRAY[126, 128]
....
That added clause is redundant to the one preceding it, but the planner is not smart enough to reason through that so you need to make it explicit.