Make index_set_state_flags() transactional
3c84046
is the original commit that introduced index_set_state_flags(), where the presence of SnapshotNow made necessary the use of an in-place update. SnapshotNow has been removed in813fb03
, so there is no actual reasons to not make this operation transactional. Note that while making the operation more robust, using a transactional operation in this routine was not strictly necessary as there was no use case for it yet. However, some future features are going to need a transactional behavior, like support for CREATE/DROP INDEX CONCURRENTLY with partitioned tables, where indexes in a partition tree need to have all their pg_index.indis* flags updated in the same transaction to make the operation stable to the end-user by keeping partition trees consistent, even with a failure mid-flight. REINDEX CONCURRENTLY uses already transactional updates when swapping the old and new indexes, making this change more consistent with the index-swapping logic. Author: Michael Paquier Reviewed-by: Anastasia Lubennikova Discussion: https://postgr.es/m/20200903080440.GA8559@paquier.xyz
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@ -3311,18 +3311,10 @@ validate_index_callback(ItemPointer itemptr, void *opaque)
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* index_set_state_flags - adjust pg_index state flags
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*
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* This is used during CREATE/DROP INDEX CONCURRENTLY to adjust the pg_index
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* flags that denote the index's state. Because the update is not
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* transactional and will not roll back on error, this must only be used as
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* the last step in a transaction that has not made any transactional catalog
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* updates!
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* flags that denote the index's state.
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*
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* Note that heap_inplace_update does send a cache inval message for the
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* Note that CatalogTupleUpdate() sends a cache invalidation message for the
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* tuple, so other sessions will hear about the update as soon as we commit.
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*
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* NB: In releases prior to PostgreSQL 9.4, the use of a non-transactional
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* update here would have been unsafe; now that MVCC rules apply even for
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* system catalog scans, we could potentially use a transactional update here
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* instead.
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*/
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void
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index_set_state_flags(Oid indexId, IndexStateFlagsAction action)
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@ -3331,9 +3323,6 @@ index_set_state_flags(Oid indexId, IndexStateFlagsAction action)
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HeapTuple indexTuple;
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Form_pg_index indexForm;
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/* Assert that current xact hasn't done any transactional updates */
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Assert(GetTopTransactionIdIfAny() == InvalidTransactionId);
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/* Open pg_index and fetch a writable copy of the index's tuple */
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pg_index = table_open(IndexRelationId, RowExclusiveLock);
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@ -3397,8 +3386,8 @@ index_set_state_flags(Oid indexId, IndexStateFlagsAction action)
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break;
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}
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/* ... and write it back in-place */
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heap_inplace_update(pg_index, indexTuple);
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/* ... and update it */
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CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
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table_close(pg_index, RowExclusiveLock);
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}
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