Someone, somewhere (on IRC or Slack), asked about logging read access to specific table.
This is interesting question with at least couple options. So, let's dig in…
Author: depesz
Stop the war in Ukraine
Since yesterday my sites (explain.depesz.com, paste.depesz.com, and this blog) are no longer available from IPs that are in Russia or Belarus.
I know this is not huge loss for them, but, I think, every single bit counts.
If you'd like to do the same thing for their site/service:
Waiting for PostgreSQL 15 – Documentation for SQL/JSON features
On 8th of April 2022, Andrew Dunstan committed patch:
Documentation for SQL/JSON features This documents the features added in commits f79b803dcc, f4fb45d15c, 33a377608f, 1a36bc9dba, 606948b058, 49082c2cc3, 4e34747c88, and fadb48b00e. I have cleaned up the aggregate section of the submitted docs, but there is still a deal of copy editing required. However, I thought it best to have some documentation sooner rather than later so testers can have a better idea what they are playing with. Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zhihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru Discussion: https://postgr.es/m/7e2cb85d-24cf-4abb-30a5-1a33715959bd@postgrespro.ru
Continue reading Waiting for PostgreSQL 15 – Documentation for SQL/JSON features
Waiting for PostgreSQL 15 – JSON_TABLE
On 4th of April 2022, Andrew Dunstan committed patch:
JSON_TABLE This feature allows jsonb data to be treated as a table and thus used in a FROM clause like other tabular data. Data can be selected from the jsonb using jsonpath expressions, and hoisted out of nested structures in the jsonb to form multiple rows, more or less like an outer join. Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zhihong Yu (whose name I previously misspelled), Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/7e2cb85d-24cf-4abb-30a5-1a33715959bd@postgrespro.ru
DBA tips ‘n tricks – search in every field in a table
Sometimes you just want to find some value, regardless of which column it's in. If the table has few columns you can easily:
=$ select * from table where a ~ '...' or b ~ '...' or c ~ '...'
But if there are many columns writing such query quickly becomes tedious. Luckily there is simple solution.
Continue reading DBA tips ‘n tricks – search in every field in a table
Waiting for PostgreSQL 15 – SQL/JSON query functions
On 29th of March 2022, Andrew Dunstan committed patch:
SQL/JSON query functions This introduces the SQL/JSON functions for querying JSON data using jsonpath expressions. The functions are: JSON_EXISTS() JSON_QUERY() JSON_VALUE() All of these functions only operate on jsonb. The workaround for now is to cast the argument to jsonb. JSON_EXISTS() tests if the jsonpath expression applied to the jsonb value yields any values. JSON_VALUE() must return a single value, and an error occurs if it tries to return multiple values. JSON_QUERY() must return a json object or array, and there are various WRAPPER options for handling scalar or multi-value results. Both these functions have options for handling EMPTY and ERROR conditions. Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Continue reading Waiting for PostgreSQL 15 – SQL/JSON query functions
Waiting for PostgreSQL 15 – IS JSON predicate
On 28th of March 2022, Andrew Dunstan
Title: Waiting for PostgreSQL 15 – IS JSON predicate
On 28th of March 2022, Andrew Dunstan committed patch:
IS JSON predicate This patch intrdocuces the SQL standard IS JSON predicate. It operates on text and bytea values representing JSON as well as on the json and jsonb types. Each test has an IS and IS NOT variant. The tests are: IS JSON [VALUE] IS JSON ARRAY IS JSON OBJECT IS JSON SCALAR IS JSON WITH | WITHOUT UNIQUE KEYS These are mostly self-explanatory, but note that IS JSON WITHOUT UNIQUE KEYS is true whenever IS JSON is true, and IS JSON WITH UNIQUE KEYS is true whenever IS JSON is true except it IS JSON OBJECT is true and there are duplicate keys (which is never the case when applied to jsonb values). Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Continue reading Waiting for PostgreSQL 15 – IS JSON predicate
Waiting for PostgreSQL 15 – SQL/JSON constructors
On 27th of March 2022, Andrew Dunstan committed patch:
SQL/JSON constructors This patch introduces the SQL/JSON standard constructors for JSON: JSON() JSON_ARRAY() JSON_ARRAYAGG() JSON_OBJECT() JSON_OBJECTAGG() For the most part these functions provide facilities that mimic existing json/jsonb functions. However, they also offer some useful additional functionality. In addition to text input, the JSON() function accepts bytea input, which it will decode and constuct a json value from. The other functions provide useful options for handling duplicate keys and null values. This series of patches will be followed by a consolidated documentation patch. Nikita Glukhov Reviewers have included (in no particular order) Andres Freund, Alexander Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu, Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby. Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Continue reading Waiting for PostgreSQL 15 – SQL/JSON constructors
Waiting for PostgreSQL 15 – Add support for MERGE SQL command
On 28th of March 2022, Alvaro Herrera committed patch:
Add support for MERGE SQL command MERGE performs actions that modify rows in the target table using a source table or query. MERGE provides a single SQL statement that can conditionally INSERT/UPDATE/DELETE rows -- a task that would otherwise require multiple PL statements. For example, MERGE INTO target AS t USING source AS s ON t.tid = s.sid WHEN MATCHED AND t.balance > s.delta THEN UPDATE SET balance = t.balance - s.delta WHEN MATCHED THEN DELETE WHEN NOT MATCHED AND s.delta > 0 THEN INSERT VALUES (s.sid, s.delta) WHEN NOT MATCHED THEN DO NOTHING; MERGE works with regular tables, partitioned tables and inheritance hierarchies, including column and row security enforcement, as well as support for row and statement triggers and transition tables therein. MERGE is optimized for OLTP and is parameterizable, though also useful for large scale ETL/ELT. MERGE is not intended to be used in preference to existing single SQL commands for INSERT, UPDATE or DELETE since there is some overhead. MERGE can be used from PL/pgSQL. MERGE does not support targetting updatable views or foreign tables, and RETURNING clauses are not allowed either. These limitations are likely fixable with sufficient effort. Rewrite rules are also not supported, but it's not clear that we'd want to support them. Author: Pavan Deolasee <pavan.deolasee@gmail.com> Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Author: Amit Langote <amitlangote09@gmail.com> Author: Simon Riggs <simon.riggs@enterprisedb.com> Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com> Reviewed-by: Andres Freund <andres@anarazel.de> (earlier versions) Reviewed-by: Peter Geoghegan <pg@bowt.ie> (earlier versions) Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier versions) Reviewed-by: Japin Li <japinli@hotmail.com> Reviewed-by: Justin Pryzby <pryzby@telsasoft.com> Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com> Reviewed-by: Zhihong Yu <zyu@yugabyte.com> Discussion: https://postgr.es/m/CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com Discussion: https://postgr.es/m/CAH2-WzkJdBuxj9PO=2QaO9-3h3xGbQPZ34kJH=HukRekwM-GZg@mail.gmail.com Discussion: https://postgr.es/m/20201231134736.GA25392@alvherre.pgsql
Continue reading Waiting for PostgreSQL 15 – Add support for MERGE SQL command
Waiting for PostgreSQL 15 – Add support for security invoker views.
On 22nd of March 2022, Dean Rasheed committed patch:
Add support for security invoker views. A security invoker view checks permissions for accessing its underlying base relations using the privileges of the user of the view, rather than the privileges of the view owner. Additionally, if any of the base relations are tables with RLS enabled, the policies of the user of the view are applied, rather than those of the view owner. This allows views to be defined without giving away additional privileges on the underlying base relations, and matches a similar feature available in other database systems. It also allows views to operate more naturally with RLS, without affecting the assignments of policies to users. Christoph Heiss, with some additional hacking by me. Reviewed by Laurenz Albe and Wolfgang Walther. Discussion: https://postgr.es/m/b66dd6d6-ad3e-c6f2-8b90-47be773da240%40cybertec.at
Continue reading Waiting for PostgreSQL 15 – Add support for security invoker views.