[EC-CUBE] EC-CUBE4.0.4
[レンタルサーバ] GCP
[OS] Linux
[PHP] PHP Version 7.3.29
[データベース] PostgreSQL 10.17
[WEBサーバ] Apache/2.4.25 (Debian)
[ブラウザ] Chrome/93.0.4577.63

お世話になっております。ECCUBE4環境で表題の現象が発生しているため、解決にご助力いただきたい次第です。
エラーの中からから数パターン抽出したログを以下に記載いたします。

DBログ
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DETAIL:  Process 436883 waits for AccessExclusiveLock on tuple (5,82) of relation 102311 of database 101784; blocked by process 434682.
ERROR:  deadlock detected
STATEMENT:  SELECT t0.id AS id_1, t0.file_name AS file_name_2, t0.sort_no AS sort_no_3, t0.create_date AS create_date_4, t0.product_id AS product_id_5, t0.creator_id AS creator_id_6, t0.discriminator_type FROM e IN ('productimage') ORDER BY t0.sort_no ASC
STATEMENT:  SELECT 1 FROM dtb_product_stock t0 WHERE t0.id = $1 AND t0.discriminator_type IN ('productstock') FOR UPDATE


DETAIL:  Process 436830 waits for AccessExclusiveLock on tuple (5,82) of relation 102311 of database 101784; blocked by process 434682.
ERROR:  deadlock detected
STATEMENT:  SELECT 1 FROM dtb_product_stock t0 WHERE t0.id = $1 AND t0.discriminator_type IN ('productstock') FOR UPDATE


DETAIL:  Process 436796 waits for AccessExclusiveLock on tuple (5,82) of relation 102311 of database 101784; blocked by process 434682.
ERROR:  deadlock detected
STATEMENT:  SELECT t0.id AS id_1, t0.pre_order_id AS pre_order_id_2, t0.order_no AS order_no_3, t0.message AS message_4, t0.name01 AS name01_5, t0.name02 AS name02_6, t0.kana01 AS kana01_7, t0.kana02 AS kana02_8, t0.company_name AS company_name_9, t0.email AS email_10, t0.phone_number AS phone_number_11, t0.postal_code AS postal_code_12, t0.addr01 AS addr01_13, t0.addr02 AS addr02_14, t0.birth AS birth_15, t0.subtotal AS subtotal_16, t0.discount AS discount_17, t0.delivery_fee_total AS delivery_fee_total_18, t0.charge AS charge_19, t0.tax AS tax_20, t0.total AS total_21, t0.payment_total AS payment_total_22, t0.payment_method AS payment_method_23, t0.note AS note_24, t0.create_date AS create_date_25, t0.update_date AS update_date_26, t0.order_date AS order_date_27, t0.payment_date AS payment_date_28, t0.currency_code AS currency_code_29, t0.complete_message AS complete_message_30, t0.complete_mail_message AS complete_mail_message_31, t0.add_point AS add_point_32, t0.use_point AS use_point_33, t0.gmo_payment_gateway_payment_status AS gmo_payment_gateway_payment_status_34, t0.customer_id AS customer_id_35, t0.country_id AS country_id_36, t0.pref_id AS pref_id_37, t0.sex_id AS sex_id_38, t0.job_id AS job_id_39, t0.payment_id AS payment_id_40, t0.device_type_id AS device_type_id_41, t0.order_status_id AS order_status_id_42, t0.order_status_id AS order_status_id_43, t0.order_status_id AS order_status_id_44, t0.discriminator_type FROM dtb_order t0 WHERE t0.pre_order_id = $1 AND t0.order_status_id = $2 AND t0.discriminator_type IN ('order') LIMIT 1
STATEMENT:  SELECT t0.id AS id_1, t0.delivery_time AS delivery_time_2, t0.sort_no AS sort_no_3, t0.visible AS visible_4, t0.create_date AS create_date_5, t0.update_date AS update_date_6, t0.delivery_id AS delivery_id_7, t0.discriminator_type FROM dtb_delivery_time t0 WHERE t0.delivery_id = $1 AND t0.discriminator_type IN ('deliverytime') ORDER BY t0.sort_no ASC
STATEMENT:  SELECT 1 FROM dtb_product_stock t0 WHERE t0.id = $1 AND t0.discriminator_type IN ('productstock') FOR UPDATE
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ご助力お願いいたします。