Hello, 

I launched the following command pg_dump for the backup of the database but it displays this error can help me please on this point

The error: 

pg_dump: Dumping the contents of table "ir_attachment" failed: PQgetCopyData() failed.

pg_dump: Error message from server: server closed the connection unexpectedly

        This probably means the server terminated abnormally

        before or while processing the request.

pg_dump: The command was: COPY public.ir_attachment (id, name, datas_fname, description, res_name, res_model, res_model_name, res_field, res_id, company_id, type, url, public, access_token, db_datas, store_fname, file_size, checksum, mimetype, index_content, active, create_uid, create_date, write_uid, write_date, key, website_id, theme_template_id, attachmenet_type_id, arp_flag, date_report, decision_attachment_id, version_id, law_project_id, law_project_version_id, bo_project_id, meeting_id, titre_rapport, remarque, bo_project_version_id) TO stdout;

and in the odoo logs file I found the following errors: 

2020-03-18 09:45:19,177 25363 ERROR arabe_arp_serv_v19 odoo.sql_db: bad query: INSERT INTO "ir_attachment" ("id", "create_uid", "create_date", "write_uid", "write_date", "active", "arp_flag", "company_id", "datas_fname", "mimetype", "name", "public", "res_id", "res_model", "type", "website_id") VALUES (nextval('ir_attachment_id_seq'), 1, (now() at time zone 'UTC'), 1, (now() at time zone 'UTC'), true, false, 1, 'web.assets_frontend.0.css', 'text/css', '/web/content/css', true, 0, 'ir.ui.view', 'binary', 1) RETURNING id
ERROR: cannot execute INSERT in a read-only transaction

please help me ??