diff options
Diffstat (limited to 'src/include/utils/rel.h')
| -rw-r--r-- | src/include/utils/rel.h | 57 |
1 files changed, 14 insertions, 43 deletions
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h index 9e28f17738a..243f3c72af9 100644 --- a/src/include/utils/rel.h +++ b/src/include/utils/rel.h @@ -66,43 +66,25 @@ typedef struct RelationData /*---------- * rd_createSubid is the ID of the highest subtransaction the rel has - * survived into or zero if the rel or its rd_node was created before the - * current top transaction. (IndexStmt.oldNode leads to the case of a new - * rel with an old rd_node.) rd_firstRelfilenodeSubid is the ID of the - * highest subtransaction an rd_node change has survived into or zero if - * rd_node matches the value it had at the start of the current top - * transaction. (Rolling back the subtransaction that - * rd_firstRelfilenodeSubid denotes would restore rd_node to the value it - * had at the start of the current top transaction. Rolling back any - * lower subtransaction would not.) Their accuracy is critical to - * RelationNeedsWAL(). - * - * rd_newRelfilenodeSubid is the ID of the highest subtransaction the - * most-recent relfilenode change has survived into or zero if not changed - * in the current transaction (or we have forgotten changing it). This - * field is accurate when non-zero, but it can be zero when a relation has - * multiple new relfilenodes within a single transaction, with one of them - * occurring in a subsequently aborted subtransaction, e.g. + * survived into; or zero if the rel was not created in the current top + * 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 occurring in a subsequently aborted + * subtransaction, e.g. * BEGIN; * TRUNCATE t; * SAVEPOINT save; * TRUNCATE t; * ROLLBACK TO save; * -- rd_newRelfilenodeSubid is now forgotten - * - * If every rd_*Subid field is zero, they are read-only outside - * relcache.c. Files that trigger rd_node changes by updating - * pg_class.reltablespace and/or pg_class.relfilenode call - * RelationAssumeNewRelfilenode() to update rd_*Subid. - * - * rd_droppedSubid is the ID of the highest subtransaction that a drop of - * the rel has survived into. In entries visible outside relcache.c, this - * is always zero. */ SubTransactionId rd_createSubid; /* rel was created in current xact */ - SubTransactionId rd_newRelfilenodeSubid; /* highest subxact changing - * rd_node to current value */ - /* see end for rd_firstRelfilenodeSubid and rd_droppedSubid */ + SubTransactionId rd_newRelfilenodeSubid; /* new relfilenode assigned in + * current xact */ Form_pg_class rd_rel; /* RELATION tuple */ TupleDesc rd_att; /* tuple descriptor */ @@ -226,10 +208,6 @@ typedef struct RelationData /* use "struct" here to avoid needing to include pgstat.h: */ struct PgStat_TableStatus *pgstat_info; /* statistics collection area */ - - SubTransactionId rd_firstRelfilenodeSubid; /* highest subxact changing - * rd_node to any value */ - SubTransactionId rd_droppedSubid; /* dropped with another Subid set */ } RelationData; @@ -542,16 +520,9 @@ typedef struct ViewOptions /* * RelationNeedsWAL * True if relation needs WAL. - * - * Returns false if wal_level = minimal and this relation is created or - * truncated in the current transaction. See "Skipping WAL for New - * RelFileNode" in src/backend/access/transam/README. - */ -#define RelationNeedsWAL(relation) \ - ((relation)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT && \ - (XLogIsNeeded() || \ - (relation->rd_createSubid == InvalidSubTransactionId && \ - relation->rd_firstRelfilenodeSubid == InvalidSubTransactionId))) + */ +#define RelationNeedsWAL(relation) \ + ((relation)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT) /* * RelationUsesLocalBuffers |