diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/commands/statscmds.c | 28 | ||||
| -rw-r--r-- | src/backend/commands/tablecmds.c | 24 |
2 files changed, 49 insertions, 3 deletions
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c index cab54c962c6..94865b395b7 100644 --- a/src/backend/commands/statscmds.c +++ b/src/backend/commands/statscmds.c @@ -378,3 +378,31 @@ RemoveStatisticsById(Oid statsOid) heap_close(relation, RowExclusiveLock); } + +/* + * Update a statistics object for ALTER COLUMN TYPE on a source column. + * + * This could throw an error if the type change can't be supported. + * If it can be supported, but the stats must be recomputed, a likely choice + * would be to set the relevant column(s) of the pg_statistic_ext tuple to + * null until the next ANALYZE. (Note that the type change hasn't actually + * happened yet, so one option that's *not* on the table is to recompute + * immediately.) + */ +void +UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum, + Oid oldColumnType, Oid newColumnType) +{ + /* + * Currently, we don't actually need to do anything here. For both + * ndistinct and functional-dependencies stats, the on-disk representation + * is independent of the source column data types, and it is plausible to + * assume that the old statistic values will still be good for the new + * column contents. (Obviously, if the ALTER COLUMN TYPE has a USING + * expression that substantially alters the semantic meaning of the column + * values, this assumption could fail. But that seems like a corner case + * that doesn't justify zapping the stats in common cases.) + * + * Future types of extended stats will likely require us to work harder. + */ +} diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index cdcb94929af..b94db89b257 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -9236,6 +9236,17 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel, Assert(defaultexpr); break; + case OCLASS_STATISTIC_EXT: + + /* + * Give the extended-stats machinery a chance to fix anything + * that this column type change would break. + */ + UpdateStatisticsForTypeChange(foundObject.objectId, + RelationGetRelid(rel), attnum, + attTup->atttypid, targettype); + break; + case OCLASS_PROC: case OCLASS_TYPE: case OCLASS_CAST: @@ -9246,6 +9257,7 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel, case OCLASS_OPERATOR: case OCLASS_OPCLASS: case OCLASS_OPFAMILY: + case OCLASS_AM: case OCLASS_AMOP: case OCLASS_AMPROC: case OCLASS_SCHEMA: @@ -9261,6 +9273,11 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel, case OCLASS_USER_MAPPING: case OCLASS_DEFACL: case OCLASS_EXTENSION: + case OCLASS_EVENT_TRIGGER: + case OCLASS_PUBLICATION: + case OCLASS_PUBLICATION_REL: + case OCLASS_SUBSCRIPTION: + case OCLASS_TRANSFORM: /* * We don't expect any of these sorts of objects to depend on @@ -9270,9 +9287,10 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel, getObjectDescription(&foundObject)); break; - default: - elog(ERROR, "unrecognized object class: %u", - foundObject.classId); + /* + * There's intentionally no default: case here; we want the + * compiler to warn if a new OCLASS hasn't been handled above. + */ } } |