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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2017-03-04 16:09:33 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2017-03-04 16:09:33 -0500 |
| commit | 807df31d19e7014df1d3621292589d3653f614f2 (patch) | |
| tree | 5054824f30c945113d1078ae98338e8b00de9d3e | |
| parent | 2cc16380a46d4c2103aa6caa6aaf0170863f8509 (diff) | |
| download | postgresql-807df31d19e7014df1d3621292589d3653f614f2.tar.gz postgresql-807df31d19e7014df1d3621292589d3653f614f2.zip | |
In rebuild_relation(), don't access an already-closed relcache entry.
This reliably fails with -DRELCACHE_FORCE_RELEASE, as reported by
Andrew Dunstan, and could sometimes fail in normal operation, resulting
in a wrong persistence value being used for the transient table.
It's not immediately clear to me what effects that might have beyond
the risk of a crash while accessing OldHeap->rd_rel->relpersistence,
but it's probably not good.
Bug introduced by commit f41872d0c, and made substantially worse by
commit 85b506bbf, which added a second such access significantly
later than the heap_close. I doubt the first reference could fail
in a production scenario, but the second one definitely could.
Discussion: https://postgr.es/m/7b52f900-0579-cda9-ae2e-de5da17090e6@2ndQuadrant.com
| -rw-r--r-- | src/backend/commands/cluster.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index 7ab4874c4bd..9e39e2f648c 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -559,6 +559,7 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose) Oid tableOid = RelationGetRelid(OldHeap); Oid tableSpace = OldHeap->rd_rel->reltablespace; Oid OIDNewHeap; + char relpersistence; bool is_system_catalog; bool swap_toast_by_content; TransactionId frozenXid; @@ -568,7 +569,8 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose) if (OidIsValid(indexOid)) mark_index_clustered(OldHeap, indexOid, true); - /* Remember if it's a system catalog */ + /* Remember info about rel before closing OldHeap */ + relpersistence = OldHeap->rd_rel->relpersistence; is_system_catalog = IsSystemRelation(OldHeap); /* Close relcache entry, but keep lock until transaction commit */ @@ -576,7 +578,7 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose) /* Create the transient table that will receive the re-ordered data */ OIDNewHeap = make_new_heap(tableOid, tableSpace, - OldHeap->rd_rel->relpersistence, + relpersistence, AccessExclusiveLock); /* Copy the heap data into the new table in the desired order */ @@ -590,7 +592,7 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose) finish_heap_swap(tableOid, OIDNewHeap, is_system_catalog, swap_toast_by_content, false, true, frozenXid, cutoffMulti, - OldHeap->rd_rel->relpersistence); + relpersistence); } |