diff options
Diffstat (limited to 'src/backend/commands')
| -rw-r--r-- | src/backend/commands/cluster.c | 11 | ||||
| -rw-r--r-- | src/backend/commands/vacuum.c | 39 |
2 files changed, 29 insertions, 21 deletions
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index cd19e35319e..322d6bb2f18 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -806,9 +806,10 @@ copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex, bool verbose, Form_pg_class relform; TupleDesc oldTupDesc PG_USED_FOR_ASSERTS_ONLY; TupleDesc newTupDesc PG_USED_FOR_ASSERTS_ONLY; - TransactionId OldestXmin; - TransactionId FreezeXid; - MultiXactId MultiXactCutoff; + TransactionId OldestXmin, + FreezeXid; + MultiXactId OldestMxact, + MultiXactCutoff; bool use_sort; double num_tuples = 0, tups_vacuumed = 0, @@ -896,8 +897,8 @@ copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex, bool verbose, * Since we're going to rewrite the whole table anyway, there's no reason * not to be aggressive about this. */ - vacuum_set_xid_limits(OldHeap, 0, 0, 0, 0, - &OldestXmin, &FreezeXid, &MultiXactCutoff); + vacuum_set_xid_limits(OldHeap, 0, 0, 0, 0, &OldestXmin, &OldestMxact, + &FreezeXid, &MultiXactCutoff); /* * FreezeXid will become the table's new relfrozenxid, and that mustn't go diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index 50a4a612e58..deec4887bec 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -945,14 +945,22 @@ get_all_vacuum_rels(int options) * The output parameters are: * - oldestXmin is the Xid below which tuples deleted by any xact (that * committed) should be considered DEAD, not just RECENTLY_DEAD. - * - freezeLimit is the Xid below which all Xids are replaced by - * FrozenTransactionId during vacuum. - * - multiXactCutoff is the value below which all MultiXactIds are removed - * from Xmax. + * - oldestMxact is the Mxid below which MultiXacts are definitely not + * seen as visible by any running transaction. + * - freezeLimit is the Xid below which all Xids are definitely replaced by + * FrozenTransactionId during aggressive vacuums. + * - multiXactCutoff is the value below which all MultiXactIds are definitely + * removed from Xmax during aggressive vacuums. * * Return value indicates if vacuumlazy.c caller should make its VACUUM * operation aggressive. An aggressive VACUUM must advance relfrozenxid up to - * FreezeLimit, and relminmxid up to multiXactCutoff. + * FreezeLimit (at a minimum), and relminmxid up to multiXactCutoff (at a + * minimum). + * + * oldestXmin and oldestMxact are the most recent values that can ever be + * passed to vac_update_relstats() as frozenxid and minmulti arguments by our + * vacuumlazy.c caller later on. These values should be passed when it turns + * out that VACUUM will leave no unfrozen XIDs/XMIDs behind in the table. */ bool vacuum_set_xid_limits(Relation rel, @@ -961,6 +969,7 @@ vacuum_set_xid_limits(Relation rel, int multixact_freeze_min_age, int multixact_freeze_table_age, TransactionId *oldestXmin, + MultiXactId *oldestMxact, TransactionId *freezeLimit, MultiXactId *multiXactCutoff) { @@ -969,7 +978,6 @@ vacuum_set_xid_limits(Relation rel, int effective_multixact_freeze_max_age; TransactionId limit; TransactionId safeLimit; - MultiXactId oldestMxact; MultiXactId mxactLimit; MultiXactId safeMxactLimit; int freezetable; @@ -1065,9 +1073,11 @@ vacuum_set_xid_limits(Relation rel, effective_multixact_freeze_max_age / 2); Assert(mxid_freezemin >= 0); + /* Remember for caller */ + *oldestMxact = GetOldestMultiXactId(); + /* compute the cutoff multi, being careful to generate a valid value */ - oldestMxact = GetOldestMultiXactId(); - mxactLimit = oldestMxact - mxid_freezemin; + mxactLimit = *oldestMxact - mxid_freezemin; if (mxactLimit < FirstMultiXactId) mxactLimit = FirstMultiXactId; @@ -1082,8 +1092,8 @@ vacuum_set_xid_limits(Relation rel, (errmsg("oldest multixact is far in the past"), errhint("Close open transactions with multixacts soon to avoid wraparound problems."))); /* Use the safe limit, unless an older mxact is still running */ - if (MultiXactIdPrecedes(oldestMxact, safeMxactLimit)) - mxactLimit = oldestMxact; + if (MultiXactIdPrecedes(*oldestMxact, safeMxactLimit)) + mxactLimit = *oldestMxact; else mxactLimit = safeMxactLimit; } @@ -1390,12 +1400,9 @@ vac_update_relstats(Relation relation, * Update relfrozenxid, unless caller passed InvalidTransactionId * indicating it has no new data. * - * Ordinarily, we don't let relfrozenxid go backwards: if things are - * working correctly, the only way the new frozenxid could be older would - * be if a previous VACUUM was done with a tighter freeze_min_age, in - * which case we don't want to forget the work it already did. However, - * if the stored relfrozenxid is "in the future", then it must be corrupt - * and it seems best to overwrite it with the cutoff we used this time. + * Ordinarily, we don't let relfrozenxid go backwards. However, if the + * stored relfrozenxid is "in the future" then it seems best to assume + * it's corrupt, and overwrite with the oldest remaining XID in the table. * This should match vac_update_datfrozenxid() concerning what we consider * to be "in the future". */ |