894af78f18
Solely relying on a relation's reltuples/relpages estimate to size the Bloom filters used by amcheck verification makes verification less effective when the estimates are very stale. In extreme cases, verification options that use Bloom filters internally could be totally ineffective, without users receiving any clear indication that certain types of corruption might easily be missed. To fix, use RelationGetNumberOfBlocks() instead of relpages to size the downlink block Bloom filter. Use the same RelationGetNumberOfBlocks() value to derive a minimum size for the heapallindexed Bloom filter, rather than completely trusting reltuples. Verification will still be reasonably effective when the projected/estimated number of Bloom filter elements is at least 1/5 of the final number of elements, which is assured by the new sizing logic. Reported-By: Alexander Korotkov Discussion: https://postgr.es/m/CAH2-Wzk0ke2J42KrNYBKu0Xovjy-sU5ub7PWjgpbsKdAQcL4OA@mail.gmail.com Backpatch: 11-, where downlink/heapallindexed verification were added. |
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| .. | ||
| expected | ||
| sql | ||
| .gitignore | ||
| Makefile | ||
| amcheck--1.0--1.1.sql | ||
| amcheck--1.0.sql | ||
| amcheck--1.1--1.2.sql | ||
| amcheck.control | ||
| verify_nbtree.c | ||