postgres

Commit Graph

Author	SHA1	Message	Date
Peter Eisentraut	a970edbed3	Fix ALTER TABLE / INHERIT with generated columns When running ALTER TABLE t2 INHERIT t1, we must check that columns in t2 that correspond to a generated column in t1 are also generated and have the same generation expression. Otherwise, this would allow creating setups that a normal CREATE TABLE sequence would not allow. Discussion: https://www.postgresql.org/message-id/22de27f6-7096-8d96-4619-7b882932ca25@2ndquadrant.com	5 years ago
Tom Lane	17958972fe	Allow a multi-row INSERT to specify DEFAULTs for a generated column. One can say "INSERT INTO tab(generated_col) VALUES (DEFAULT)" and not draw an error. But the equivalent case for a multi-row VALUES list always threw an error, even if one properly said DEFAULT in each row. Fix that. While here, improve the test cases for nearby logic about OVERRIDING SYSTEM/USER values. Dean Rasheed Discussion: https://postgr.es/m/9q0sgcr416t.fsf@gmx.us	5 years ago
Peter Eisentraut	bf797a8d97	Disallow ALTER TABLE ONLY / DROP EXPRESSION The current implementation cannot handle this correctly, so just forbid it for now. GENERATED clauses must be attached to the column definition and cannot be added later like DEFAULT, so if a child table has a generation expression that the parent does not have, the child column will necessarily be an attlocal column. So to implement ALTER TABLE ONLY / DROP EXPRESSION, we'd need extra code to update attislocal of the direct child tables, somewhat similar to how DROP COLUMN does it, so that the resulting state can be properly dumped and restored. Discussion: https://www.postgresql.org/message-id/flat/15830.1575468847%40sss.pgh.pa.us	5 years ago
Peter Eisentraut	086ffddf36	Fix several DDL issues of generated columns versus inheritance Several combinations of generated columns and inheritance in CREATE TABLE were not handled correctly. Specifically: - Disallow a child column specifying a generation expression if the parent column is a generated column. The child column definition must be unadorned and the parent column's generation expression will be copied. - Prohibit a child column of a generated parent column specifying default values or identity. - Allow a child column of a not-generated parent column specifying itself as a generated column. This previously did not work, but it was possible to arrive at the state via other means (involving ALTER TABLE), so it seems sensible to support it. Add tests for each case. Also add documentation about the rules involving generated columns and inheritance. Discussion: https://www.postgresql.org/message-id/flat/15830.1575468847%40sss.pgh.pa.us https://www.postgresql.org/message-id/flat/2678bad1-048f-519a-ef24-b12962f41807%40enterprisedb.com https://www.postgresql.org/message-id/flat/CAJvUf_u4h0DxkCMCeEKAWCuzGUTnDP-G5iVmSwxLQSXn0_FWNQ%40mail.gmail.com	6 years ago
David Rowley	3cb02e307e	Fix possible crash with GENERATED ALWAYS columns In some corner cases, this could also lead to corrupted values being included in the tuple. Users who are concerned that they are affected by this should first upgrade and then perform a base backup of their database and restore onto an off-line server. They should then query each table with generated columns to ensure there are no rows where the generated expression does not match a newly calculated version of the GENERATED ALWAYS expression. If no crashes occur and no rows are returned then you're not affected. Fixes bug #16369. Reported-by: Cameron Ezell Discussion: https://postgr.es/m/16369-5845a6f1bef59884@postgresql.org Backpatch-through: 12 (where GENERATED ALWAYS columns were added.)	6 years ago
Peter Eisentraut	f595117e24	ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION Add an ALTER TABLE subcommand for dropping the generated property from a column, per SQL standard. Reviewed-by: Sergei Kornilov <sk@zsrv.org> Discussion: https://www.postgresql.org/message-id/flat/2f7f1d9c-946e-0453-d841-4f38eb9d69b6%402ndquadrant.com	6 years ago
Tom Lane	4ac8aaa36f	Fix handling of generated columns in ALTER TABLE. ALTER TABLE failed if a column referenced in a GENERATED expression had been added or changed in type earlier in the ALTER command. That's because the GENERATED expression needs to be evaluated against the table's updated tuples, but it was being evaluated against the original tuples. (Fortunately the executor has adequate cross-checks to notice the mismatch, so we just got an obscure error message and not anything more dangerous.) Per report from Andreas Joseph Krogh. Back-patch to v12 where GENERATED was added. Discussion: https://postgr.es/m/VisenaEmail.200.231b0a41523275d0.16ea7f800c7@tc7-visena	6 years ago
Peter Eisentraut	66a4bad83a	Convert ExecComputeStoredGenerated to use tuple slots This code was still using the old style of forming a heap tuple rather than using tuple slots. This would be less efficient if a non-heap access method was used. And using tuple slots is actually quite a bit faster when using heap as well. Also add some test cases for generated columns with null values and with varlena values. This lack of coverage was discovered while working on this patch. Discussion: https://www.postgresql.org/message-id/flat/20190331025744.ugbsyks7czfcoksd%40alap3.anarazel.de	7 years ago
Peter Eisentraut	7241911782	Catch syntax error in generated column definition The syntax GENERATED BY DEFAULT AS (expr) is not allowed but we have to accept it in the grammar to avoid shift/reduce conflicts because of the similar syntax for identity columns. The existing code just ignored this, incorrectly. Add an explicit error check and a bespoke error message. Reported-by: Justin Pryzby <pryzby@telsasoft.com>	7 years ago
Peter Eisentraut	fc22b6623b	Generated columns This is an SQL-standard feature that allows creating columns that are computed from expressions rather than assigned, similar to a view or materialized view but on a column basis. This implements one kind of generated column: stored (computed on write). Another kind, virtual (computed on read), is planned for the future, and some room is left for it. Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/b151f851-4019-bdb1-699e-ebab07d2f40a@2ndquadrant.com	7 years ago

10 Commits (84f5c2908dad81e8622b0406beea580e40bb03ac)