From 64190d65f2995203df401738b77adc5ebd4d2fce Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Tue, 4 May 2021 11:45:37 +0200 Subject: 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 --- src/backend/commands/tablecmds.c | 60 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) (limited to 'src/backend/commands/tablecmds.c') diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index faba2641352..44499ec08b3 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -13909,6 +13909,66 @@ MergeAttributesIntoExisting(Relation child_rel, Relation parent_rel) errmsg("column \"%s\" in child table must be marked NOT NULL", attributeName))); + /* + * If parent column is generated, child column must be, too. + */ + if (attribute->attgenerated && !childatt->attgenerated) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("column \"%s\" in child table must be a generated column", + attributeName))); + + /* + * Check that both generation expressions match. + * + * The test we apply is to see whether they reverse-compile to the + * same source string. This insulates us from issues like whether + * attributes have the same physical column numbers in parent and + * child relations. (See also constraints_equivalent().) + */ + if (attribute->attgenerated && childatt->attgenerated) + { + TupleConstr *child_constr = child_rel->rd_att->constr; + TupleConstr *parent_constr = parent_rel->rd_att->constr; + char *child_expr = NULL; + char *parent_expr = NULL; + + Assert(child_constr != NULL); + Assert(parent_constr != NULL); + + for (int i = 0; i < child_constr->num_defval; i++) + { + if (child_constr->defval[i].adnum == childatt->attnum) + { + child_expr = + TextDatumGetCString(DirectFunctionCall2(pg_get_expr, + CStringGetTextDatum(child_constr->defval[i].adbin), + ObjectIdGetDatum(child_rel->rd_id))); + break; + } + } + Assert(child_expr != NULL); + + for (int i = 0; i < parent_constr->num_defval; i++) + { + if (parent_constr->defval[i].adnum == attribute->attnum) + { + parent_expr = + TextDatumGetCString(DirectFunctionCall2(pg_get_expr, + CStringGetTextDatum(parent_constr->defval[i].adbin), + ObjectIdGetDatum(parent_rel->rd_id))); + break; + } + } + Assert(parent_expr != NULL); + + if (strcmp(child_expr, parent_expr) != 0) + ereport(ERROR, + (errcode(ERRCODE_DATATYPE_MISMATCH), + errmsg("column \"%s\" in child table has a conflicting generation expression", + attributeName))); + } + /* * OK, bump the child column's inheritance count. (If we fail * later on, this change will just roll back.) -- cgit v1.2.3