Conquering JSONB in PostgreSQL

CONQUERING
JSONB IN
POSTGRESQL
Ines Panker

Why did PostgreSQL add a
JSON data type?

Postgre SQL and NoSQL
Postgre 9.4 (December 2014) JSONB: Binary format, slower input, faster processing
JSON: Exact copy, same orderPostgre 9.2
No explicit
schema
Key-Value pairs in JSON are equal to
Key-Value pairs in columns

CREATE TABLE "PaymentRequest" (
"ID" bigint PRIMARY KEY NOT NULL,
"Created" timestamp without time zone,
"LastEdited" timestamp without time zone,
"Identifier" character varying(50),
"FinalPrice" double precision,
...,
"DeliveryTypeJSON" jsonb,
"DeliveryAddressJSON" jsonb,
"InvoiceAddressJSON" jsonb,
"PromotionCodeJSON" jsonb,
"PaymentJSON" jsonb);
CREATE TABLE "PaymentRequestEntry" (
"ID" bigint PRIMARY KEY NOT NULL,
"CartCount" integer DEFAULT 0,
"PriceWithTax" double precision,
"FullPriceWithTax" double precision,
"PriceNoTax" double precision,
"FullPriceNoTax" double precision,
...,
"ShopProductJSON" jsonb,
"PaymentRequestID" integer DEFAULT 0,
"VoucherID" integer DEFAULT 0
);

class ShopProduct{
private function DataForInvoice() {
$data = array(
'SKU' => $this->SKU,
'Title' => $this->LocaleTitle(),
'Variant' => $this->Variant,
'PriceWithTax' => $this->PriceWithTax(),
'PriceNoTax' => $this->PriceNoTax(),
'DiscountPriceWithTax'=> $this->PriceWithTax(true),
'DiscountPriceNoTax' => $this->PriceNoTax(true),
'Promotion' => $this->Promotion()->DataForInvoice(),
'TaxRate' => $this->TaxRate($nice = false),
'TaxPriceOfOne' => $this->TaxOfOneProduct(),
'NoTax' => $this->NoTax(),
'AllowOneStepTransaction' => $this->AllowOneStepTransaction,
'IsVoucher' => $this->IsVoucher,
....
);
return $data;
}
}

INSERT INTO "PaymentRequestEntry" VALUES (
1,
21.60,
24.00,
17.70,
19.67,
...,
'{
"SKU":"LJCRD-24-ADL",
"Title": "Visit Ljubljana Card, 24 hours",
"Variant": "Adult",
"PriceWithTax": 24.00,
"PriceNoTax": 19.67,
...,
"Promotion": {
"Code": "SUMMER17",
"DiscountPercent": 10.00,
"DiscountAmount": null,
"ActiveFrom": "2017-05-15 00:00:00"
"ActiveTo": "2017-06-15 00:00:00"
}
"TaxRate": 0.22
}',
845623
);
ERROR: invalid input syntax for type json

"ShopProductJSON"
-----------------------------------------------
{
"SKU": "LJCRD-24-ADL",
"NoTax": false,
"Title": "Visit Ljubljana Card, 24 hours",
"TaxRate": 0.22,
"Variant": "Adult",
"IsVoucher": false,
"Promotion": {
"Code": "SUMMER17",
"ActiveTo": "2017-06-15 00:00:00",
"ActiveFrom": "2017-05-15 00:00:00",
"DiscountAmount": null,
"DiscountPercent": "10.00"
},
"PriceNoTax": 19.67,
"TaxRateNice": 0.22,
"PriceWithTax": 24.00,
"DiscountPriceNoTax": 17.70,
"DiscountPriceWithTax": 21.60,
"AllowOneStepTransaction": 1,
...
}
SELECT "ShopProductJSON" FROM "PaymentRequestEntry" WHERE "ID" = 1

select
"ID",
"WholePriceWithTax",
"NumberOfItems",
"ShopProductJSON"->>'SKU' AS "SKU",
"ShopProductJSON"->>'Title' as "Title",
"ShopProductJSON"->>'PriceWithTax' as "PriceWithTax",
"ShopProductJSON" from "PaymentRequestEntry"
WHERE "PaymentRequestID" = 1
ID
WholePrice
WithTax
NumberOf
Items SKU Title
PriceWith
Tax
1 21.6 1 LJCRD-24-ADL
Visit Ljubljana Card, 2
4 hours
24
2 90 2 TOUR-BIKE-24 Bike tour of Ljubljana 45
3 387 2 WC-17 WebCamp 2017 15

JSON Operators: ->
arrays objects
int text
SELECT '["a",2,"3"]'::json->0 as data
data (json)
------------------
"a"
data (json)
------------------
2
data (json)
------------------
"3"
SELECT '["a",2,"3"]'::json->'a' as data
data (json)
------------------
SELECT '{"a":1,"b":2}'::json->'b' as data
data (json)
------------------
2
SELECT '{"a":1,"b":{"c":[1,2]}}'::json->'b'
data (json)
------------------
{"c":[1,2]}
json json

JSON Operators: ->>
arrays
int
SELECT '["a",2,"3"]'::json->>0 as data
data (text)
------------------
"a"
SELECT '["a",2,"3"]'::json->>1 > 1
ERROR: operator does not exist: text >
integer
SELECT ('["a",2,"3"]'::json->>1)::int > 1
data (boolean)
---------------
t
SELECT ('["a",2,"3"]'::json->1)::int > 1
ERROR: cannot cast type json to integer
text

JSON Operators: ->>
SELECT '{"a":1,"b":"word"}'::json->>'b'
data (text)
------------------
"word"
SELECT '{"a":1,"b":"word"}'::json->>'b' = 'word'
data(boolean)
-----------
t
SELECT
'{
"identifier":1mo3j4,
"items":[
{
"mon":"Monday",
"tue":"Tuesday"
},
{
"jan":"january",
"feb":"february"
}
]
}'::json->'items'->0->>'tue'
data (text)
--------------
"Tuesday"
objects
text text

JSON Operators: #>, #>>
SELECT
'{
"id":1,
"items":[
{
"mon":"Monday",
"tue":"Tuesday"
},
{
"jan":"january",
"feb":"february"
}
]
}'::json #>> '{items,0,tue}'
data (text)
--------------
"Tuesday"
SELECT
'{
"id":1,
"items":[
{
"mon":"Monday",
"tue":"Tuesday"
},
{
"jan":"january",
"feb":"february"
}
]
}'::json ->'items'->0->>'tue'
data (text)
--------------
"Tuesday"
objects
array of text text

JSONB Operators: @>, ?
SELECT
'{
"promotion":
{
"code":"SUMMER17",
"discount":"10"
}
}'::jsonb ? 'promotion'
SELECT
'{
"promotion":
{
"code":"SUMMER17",
"discount":"10"
}
}'::jsonb->'promotion' ? 'code'
SELECT
'{
"id":1,
"promotion":
{
"code":"SUMMER17",
"discount":"10"
}
}'::jsonb @> '{"promotion":{"code":
"SUMMER17"}}'
data (boolean)
--------------
t
objects
text boolean
objects
jsonb boolean

SELECT count("ID") as number_of_products_promo_was_used
FROM "PaymentRequestEntry"
WHERE "ShopProductJSON" @> '{"Promotion":{"Code": "SUMMER17"}}'
{
"SKU": "LJCRD-24-ADL",
"IsVoucher": false,
"Promotion": {
"Code": "SUMMER17",
},
"PriceNoTax": "19.67",
"TaxRateNice": "0.22",
"PriceWithTax": "24.00",
"DiscountPriceNoTax": "10.00",
"DiscountPriceWithTax": "10.00",
}
SELECT
"PaymentRequestID",
sum(("ShopProductJSON"->>'PriceWithTax')::float)
- sum(("ShopProductJSON"->>'DiscountPriceWithTax')::float) as money_saved
WHERE "ShopProductJSON" @> '{"Promotion":{"Code": "SUMMER17"}}‘
GROUP BY "PaymentRequestID"
PaymentRequestID money_saved
845623 5.12
845622 6.01
845625 2.2
...

SELECT
SUM("CartCount") AS number_of_products,
SUM(("ShopProductJSON"->>'PriceWithTax')::float) -
SUM(("ShopProductJSON"->>'DiscountPriceWithTax')::float) AS
money_saved,
r."DeliveryAddressJSON"->>'Country' AS country
FROM "PaymentRequestEntry" e
INNER JOIN "PaymentRequest" r ON r."ID" = e."PaymentRequestID"
WHERE "ShopProductJSON"->'Promotion'->>'Code' = 'SUMMER17'
GROUP BY r."DeliveryAddressJSON"->>'Country'
ORDER BY money_saved
number_of_products money_saved country
481 1503.72 DE
512 1438.56 AT
503 1289.05 IT
...

SELECT
sp."CalculatedPrice",
e."ShopProductJSON"->>'PriceWithTax' as bought_price,
e."Created"
FROM "PaymentRequestEntry" e
INNER JOIN "ShopProduct" sp
ON sp."SKU" = e."ShopProductJSON"->>'SKU'
AND e."ShopProductJSON" @> '{"SKU": "LJCRD-24-ADL"}'
ORDER BY e."Created" desc
CalculatedPrice bought_price Created
24 24 2017-04-21 15:23:01
24 21.6 2017-04-21 15:22:12
...
24 22 2016-12-01 07:17:53
...

EXPLAIN SELECT *
Seq Scan on "PaymentRequestEntry" (cost=0.00..21.02 rows=3 width=100)
Filter: ((("ShopProductJSON" -> 'Promotion'::text) ->> 'Code'::text) =
'SUMMER17'::text)
GIN index
over the
WHOLE JSON
for only 1 key
in the JSON
jsonb_ops :
bigger & more
versatily
jsonb_path_ops:
smaller & supports
only @> querys

EXPLAIN SELECT * FROM "PaymentRequestEntry"
Seq Scan on "PaymentRequestEntry" (cost=0.00..511091.51 rows=3662
width=85)
table "PaymentRequestEntry" size: 3635 MB, 2.807.147 rows
CREATE index json_index ON "PaymentRequestEntry"
USING GIN (("ShopProductJSON"->'Promotion'->'Code'))
USING GIN ("ShopProductJSON")
@> <@
? ?| ?&
USING GIN ("ShopProductJSON" jsonb_path_ops)
@>
indexname num_rows index_size
json_index_ops 2.807.147 10 MB
json_index_path_ops 2.807.147 7.832 MB (-20%)
json_index_column 2.807.147 3.112 MB (-70%)
json_index_column_path 2.807.147 3.112 MB (-70%)
1.
2.
3.

What have we used JSON
data types for so far?

JSON to Form
{
"type":"object",
"title":"Comment",
"properties":{
"name":{
"title":"Name",
"type":"string"
},
"email":{
"title":"Email",
"type":"string",
"pattern":"^S+@S+$",
"description":"Email will be used for evil."
},
"comment":{
"title":"Comment",
"type":"string",
"maxLength":20,
"validationMessage":"Don't be greedy!"
}
},
"required":[
"name",
"email",
"comment"
]
}

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