From 48e6c943e5f11f5d80cabdbcd98f79e3dbad1988 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 18 Feb 2016 15:40:35 -0500 Subject: Fix multiple bugs in contrib/pgstattuple's pgstatindex() function. Dead or half-dead index leaf pages were incorrectly reported as live, as a consequence of a code rearrangement I made (during a moment of severe brain fade, evidently) in commit d287818eb514d431. The index metapage was not counted in index_size, causing that result to not agree with the actual index size on-disk. Index root pages were not counted in internal_pages, which is inconsistent compared to the case of a root that's also a leaf (one-page index), where the root would be counted in leaf_pages. Aside from that inconsistency, this could lead to additional transient discrepancies between the reported page counts and index_size, since it's possible for pgstatindex's scan to see zero or multiple pages marked as BTP_ROOT, if the root moves due to a split during the scan. With these fixes, index_size will always be exactly one page more than the sum of the displayed page counts. Also, the index_size result was incorrectly documented as being measured in pages; it's always been measured in bytes. (While fixing that, I couldn't resist doing some small additional wordsmithing on the pgstattuple docs.) Including the metapage causes the reported index_size to not be zero for an empty index. To preserve the desired property that the pgstattuple regression test results are platform-independent (ie, BLCKSZ configuration independent), scale the index_size result in the regression tests. The documentation issue was reported by Otsuka Kenji, and the inconsistent root page counting by Peter Geoghegan; the other problems noted by me. Back-patch to all supported branches, because this has been broken for a long time. --- contrib/pgstattuple/pgstatindex.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) (limited to 'contrib/pgstattuple/pgstatindex.c') diff --git a/contrib/pgstattuple/pgstatindex.c b/contrib/pgstattuple/pgstatindex.c index 8048a2cbe7c..9f1377c4cd9 100644 --- a/contrib/pgstattuple/pgstatindex.c +++ b/contrib/pgstattuple/pgstatindex.c @@ -79,7 +79,6 @@ typedef struct BTIndexStat uint32 level; BlockNumber root_blkno; - uint64 root_pages; uint64 internal_pages; uint64 leaf_pages; uint64 empty_pages; @@ -185,7 +184,6 @@ pgstatindex_impl(Relation rel, FunctionCallInfo fcinfo) } /* -- init counters -- */ - indexStat.root_pages = 0; indexStat.internal_pages = 0; indexStat.leaf_pages = 0; indexStat.empty_pages = 0; @@ -218,7 +216,11 @@ pgstatindex_impl(Relation rel, FunctionCallInfo fcinfo) /* Determine page type, and update totals */ - if (P_ISLEAF(opaque)) + if (P_ISDELETED(opaque)) + indexStat.deleted_pages++; + else if (P_IGNORE(opaque)) + indexStat.empty_pages++; /* this is the "half dead" state */ + else if (P_ISLEAF(opaque)) { int max_avail; @@ -235,12 +237,6 @@ pgstatindex_impl(Relation rel, FunctionCallInfo fcinfo) if (opaque->btpo_next != P_NONE && opaque->btpo_next < blkno) indexStat.fragments++; } - else if (P_ISDELETED(opaque)) - indexStat.deleted_pages++; - else if (P_IGNORE(opaque)) - indexStat.empty_pages++; - else if (P_ISROOT(opaque)) - indexStat.root_pages++; else indexStat.internal_pages++; @@ -269,7 +265,7 @@ pgstatindex_impl(Relation rel, FunctionCallInfo fcinfo) values[j++] = psprintf("%d", indexStat.version); values[j++] = psprintf("%d", indexStat.level); values[j++] = psprintf(INT64_FORMAT, - (indexStat.root_pages + + (1 + /* include the metapage in index_size */ indexStat.leaf_pages + indexStat.internal_pages + indexStat.deleted_pages + -- cgit v1.2.3