diff options
Diffstat (limited to 'src/include/utils/rel.h')
| -rw-r--r-- | src/include/utils/rel.h | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h index f7f84e6f71e..ff5488a7d8b 100644 --- a/src/include/utils/rel.h +++ b/src/include/utils/rel.h @@ -90,11 +90,20 @@ typedef struct RelationData /* * rd_createSubid is the ID of the highest subtransaction the rel has * survived into; or zero if the rel was not created in the current top - * transaction. This should be relied on only for optimization purposes; - * it is possible for new-ness to be "forgotten" (eg, after CLUSTER). + * transaction. This can be now be relied on, whereas previously it + * could be "forgotten" in earlier releases. * Likewise, rd_newRelfilenodeSubid is the ID of the highest * subtransaction the relfilenode change has survived into, or zero if not * changed in the current transaction (or we have forgotten changing it). + * rd_newRelfilenodeSubid can be forgotten when a relation has multiple + * new relfilenodes within a single transaction, with one of them occuring + * in a subsequently aborted subtransaction, e.g. + * BEGIN; + * TRUNCATE t; + * SAVEPOINT save; + * TRUNCATE t; + * ROLLBACK TO save; + * -- rd_newRelfilenode is now forgotten */ SubTransactionId rd_createSubid; /* rel was created in current xact */ SubTransactionId rd_newRelfilenodeSubid; /* new relfilenode assigned in |