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## Problem https://github.com/neondatabase/neon/issues/9240 ## Summary of changes Correctly truncate VM page instead just replacing it with zero page. ## Checklist before requesting a review - [ ] I have performed a self-review of my code. - [ ] If it is a core feature, I have added thorough tests. - [ ] Do we need to implement analytics? if so did you add the relevant metrics to the dashboard? - [ ] If this PR requires public announcement, mark it with /release-notes label and add several sentences in this section. ## Checklist before merging - [ ] Do not forget to reformat commit message to not include the above checklist --------- Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech> Co-authored-by: Heikki Linnakangas <heikki@neon.tech>
34 lines
1.4 KiB
Python
34 lines
1.4 KiB
Python
from fixtures.neon_fixtures import NeonEnv
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#
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# Test that VM is properly truncated
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#
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def test_vm_truncate(neon_simple_env: NeonEnv):
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env = neon_simple_env
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endpoint = env.endpoints.create_start("main")
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con = endpoint.connect()
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cur = con.cursor()
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cur.execute("CREATE EXTENSION neon_test_utils")
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cur.execute("CREATE EXTENSION pageinspect")
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cur.execute(
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"create table t(pk integer primary key, counter integer default 0, filler text default repeat('?', 200))"
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)
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cur.execute("insert into t (pk) values (generate_series(1,1000))")
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cur.execute("delete from t where pk>10")
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cur.execute("vacuum t") # truncates the relation, including its VM and FSM
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# get image of the first block of the VM excluding the page header. It's expected
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# to still be in the buffer cache.
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# ignore page header (24 bytes, 48 - it's hex representation)
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cur.execute("select substr(encode(get_raw_page('t', 'vm', 0), 'hex'), 48)")
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pg_bitmap = cur.fetchall()[0][0]
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# flush shared buffers
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cur.execute("SELECT clear_buffer_cache()")
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# now download the first block of the VM from the pageserver ...
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cur.execute("select substr(encode(get_raw_page('t', 'vm', 0), 'hex'), 48)")
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ps_bitmap = cur.fetchall()[0][0]
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# and check that content of bitmaps are equal, i.e. PS is producing the same VM page as Postgres
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assert pg_bitmap == ps_bitmap
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