From 9ad7e15507ffa14f51d80d6ae3ed942ea191826d Mon Sep 17 00:00:00 2001 From: Tom Lane 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 2ccb996112..6c81d57c85 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); } -- 2.40.0