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cd4868a570
Getting from get_raw_page() an all-zero page is considered as a valid case by the buffer manager and it can happen for example when finding a corrupted page with zero_damaged_pages enabled (using zero_damaged_pages to look at corrupted pages happens), or after a crash when a relation file is extended before any WAL for its new data is generated (before a vacuum or autovacuum job comes in to do some cleanup). However, all the functions of pageinspect, as of the index AMs (except hash that has its own idea of new pages), heap, the FSM or the page header have never worked with all-zero pages, causing various crashes when going through the page internals. This commit changes all the pageinspect functions to be compliant with all-zero pages, where the choice is made to return NULL or no rows for SRFs when finding a new page. get_raw_page() still works the same way, returning a batch of zeros in the bytea of the page retrieved. A hard error could be used but NULL, while more invasive, is useful when scanning relation files in full to get a batch of results for a single relation in one query. Tests are added for all the code paths impacted. Reported-by: Daria Lepikhova Author: Michael Paquier Discussion: https://postgr.es/m/561e187b-3549-c8d5-03f5-525c14e65bd0@postgrespro.ru Backpatch-through: 10
38 lines
1.5 KiB
SQL
38 lines
1.5 KiB
SQL
CREATE TABLE test1 (a int, b text);
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INSERT INTO test1 VALUES (1, 'one');
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CREATE INDEX test1_a_idx ON test1 USING brin (a);
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SELECT brin_page_type(get_raw_page('test1_a_idx', 0));
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SELECT brin_page_type(get_raw_page('test1_a_idx', 1));
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SELECT brin_page_type(get_raw_page('test1_a_idx', 2));
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SELECT * FROM brin_metapage_info(get_raw_page('test1_a_idx', 0));
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SELECT * FROM brin_metapage_info(get_raw_page('test1_a_idx', 1));
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SELECT * FROM brin_revmap_data(get_raw_page('test1_a_idx', 0)) LIMIT 5;
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SELECT * FROM brin_revmap_data(get_raw_page('test1_a_idx', 1)) LIMIT 5;
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SELECT * FROM brin_page_items(get_raw_page('test1_a_idx', 2), 'test1_a_idx')
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ORDER BY blknum, attnum LIMIT 5;
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-- Failure for non-BRIN index.
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CREATE INDEX test1_a_btree ON test1 (a);
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SELECT brin_page_items(get_raw_page('test1_a_btree', 0), 'test1_a_btree');
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-- Mask DETAIL messages as these are not portable across architectures.
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\set VERBOSITY terse
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-- Invalid special area size
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SELECT brin_page_type(get_raw_page('test1', 0));
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SELECT * FROM brin_metapage_info(get_raw_page('test1', 0));
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SELECT * FROM brin_revmap_data(get_raw_page('test1', 0));
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\set VERBOSITY default
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-- Tests with all-zero pages.
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SHOW block_size \gset
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SELECT brin_page_type(decode(repeat('00', :block_size), 'hex'));
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SELECT brin_page_items(decode(repeat('00', :block_size), 'hex'), 'test1_a_idx');
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SELECT brin_metapage_info(decode(repeat('00', :block_size), 'hex'));
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SELECT brin_revmap_data(decode(repeat('00', :block_size), 'hex'));
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DROP TABLE test1;
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