confirmed:
SQL fout:

ERROR: invalid input syntax for integer: ""
LINE 1: ..."ucm_type_id","ucm_language_id") VALUES ('6', '70', '1', '')
^

In statement:
INSERT INTO "j336_ucm_base" ("ucm_id","ucm_item_id","ucm_type_id","ucm_language_id") VALUES ('6', '70', '1', '')

@test: ok
Issue reproduced. Applied PR, PR resolves issue.

Next problem:
SQL fout:

ERROR: duplicate key value violates unique constraint "j336_ucm_content_idx_type_alias_item_id"
DETAIL: Key (core_type_alias, core_content_item_id)=(com_content.article, 69) already exists.

In statement:

INSERT INTO "j336_ucm_content" ("core_type_alias","core_title","core_alias","core_body","core_state","core_access","core_params","core_featured","core_metadata","core_created_user_id","core_created_time","core_modified_time","core_language","core_publish_up","core_publish_down","core_content_item_id","core_images","core_urls","core_hits","core_version","core_ordering","core_metakey","core_metadesc","core_catid","core_xreference","core_type_id") VALUES ('com_content.article','Quick Icons','quick-icons','

The Quick Icon plugin group is used to provide notification that updates to Joomla! or installed extensions are available and should be applied. These notifications display on your administrator control panel, which is the page you see when you first log in to your site administrator.

Default on:

Quick icon - Joomla! extensions updates notification Help.
Quick icon - Joomla! update notification Help

',1,1,'{"show_title":"","link_titles":"","show_tags":"","show_intro":"","info_block_position":"","show_category":"","link_category":"","show_parent_category":"","link_parent_category":"","show_author"

Was this on trying to save the quick icons' article?

Unsuccessful test. Got the following error;

Error
Save failed with the following error: Database query failed (error # %s): %s SQL=INSERT INTO "pt6uv_ucm_content" ("core_type_alias","core_title","core_alias","core_body","core_state","core_access","core_params","core_featured","core_metadata","core_created_user_id","core_created_time","core_modified_time","core_language","core_publish_up","core_publish_down","core_content_item_id","core_images","core_urls","core_hits","core_version","core_ordering","core_metakey","core_metadesc","core_catid","core_xreference","core_type_id") VALUES ('com_content.article','Breadcrumbs Module','breadcrumbs-module','

Breadcrumbs provide a pathway for users to navigate through the site. Help

{loadmodule breadcrumbs,breadcrumbs}
',1,1,'{"show_title":"","link_titles":"","show_tags":"","show_intro":"","info_block_position":"","show_category":"","link_category":"","show_parent_category":"","link_parent_category":"","show_author":"","link_author":"","show_create_date":"","show_modify_date":"","show_publish_date":"","show_item_navigation":"","show_icons":"","show_print_icon":"","show_email_icon":"","show_vote":"","show_hits":"","show_noauth":"","urls_position":"","alternative_readmore":"","article_layout":"","show_publishing_options":"","show_article_options":"","show_urls_images_backend":"","show_urls_images_frontend":""}',0,'{"robots":"","author":"","rights":"","xreference":""}',437,'2011-01-01 00:00:01','2014-10-19 16:31:08','*','2011-01-01 00:00:01','1970-01-01 00:00:00',61,'{"image_intro":"","float_intro":"","image_intro_alt":"","image_intro_caption":"","image_fulltext":"","float_fulltext":"","image_fulltext_alt":"","image_fulltext_caption":""}','{"urla":false,"urlatext":"","targeta":"","urlb":false,"urlbtext":"","targetb":"","urlc":false,"urlctext":"","targetc":""}',0,5,2,'','',75,'',1) RETURNING core_content_id

RTC Thanks for testing guys!

@wilsonge Yes, that is what is mentioned in the title!
Currently investigating whether we should use pg_result_error instead of pg_last_error. Pretty annoying not seeing the database error like in phpPgAdmin.

This comment was created with the J!Tracker Application at issues.joomla.org/joomla-cms/4852.

I agree. That would be a useful fix if we could see those errors! Umm I'm not getting that error but i've been playing around with all kinds of things on localhost setup. I'm gonna wait for a maintainer to merge all the RTC postgres issues then start again and work through what I can find

Same thought here.

Merged into staging. Thanks!

So me and @Bakual did some research into the other sql error you guys both saw. Turns out that when you try and save a tag before this patch it inserts the data into the #__ucm_content table successfully but failed at the #__ucm_base table. It then tried to reinsert into both tables after the patch. That meant that on any article you'd previously tried attaching a tag to it gave the error you gave above. On any other article it would be fine