From 9ad7e15507ffa14f51d80d6ae3ed942ea191826d Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 20 Apr 2011 19:01:20 -0400
Subject: [PATCH] Set indcheckxmin true when REINDEX fixes an invalid or
not-ready index.
Per comment from Greg Stark, it's less clear that HOT chains don't conflict
with the index than it would be for a valid index. So, let's preserve the
former behavior that indcheckxmin does get set when there are
potentially-broken HOT chains in this case. This change does not cause any
pg_index update that wouldn't have happened anyway, so we're not
re-introducing the previous bug with pg_index updates, and surely the case
is not significant from a performance standpoint; so let's be as
conservative as possible.
---
src/backend/catalog/index.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 2ccb9961122..6c81d57c85f 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2800,7 +2800,12 @@ reindex_index(Oid indexId, bool skip_constraint_checks)
*
* We can also reset indcheckxmin, because we have now done a
* non-concurrent index build, *except* in the case where index_build
- * found some still-broken HOT chains.
+ * found some still-broken HOT chains. If it did, we normally leave
+ * indcheckxmin alone (note that index_build won't have changed it,
+ * because this is a reindex). But if the index was invalid or not ready
+ * and there were broken HOT chains, it seems best to force indcheckxmin
+ * true, because the normal argument that the HOT chains couldn't conflict
+ * with the index is suspect for an invalid index.
*
* Note that it is important to not update the pg_index entry if we don't
* have to, because updating it will move the index's usability horizon
@@ -2825,10 +2830,12 @@ reindex_index(Oid indexId, bool skip_constraint_checks)
if (!indexForm->indisvalid || !indexForm->indisready ||
(indexForm->indcheckxmin && !indexInfo->ii_BrokenHotChain))
{
- indexForm->indisvalid = true;
- indexForm->indisready = true;
if (!indexInfo->ii_BrokenHotChain)
indexForm->indcheckxmin = false;
+ else if (!indexForm->indisvalid || !indexForm->indisready)
+ indexForm->indcheckxmin = true;
+ indexForm->indisvalid = true;
+ indexForm->indisready = true;
simple_heap_update(pg_index, &indexTuple->t_self, indexTuple);
CatalogUpdateIndexes(pg_index, indexTuple);
}
--
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