mirror of
https://github.com/kevinveenbirkenbach/docker-volume-backup.git
synced 2026-08-01 12:34:50 +00:00
Kevin Veen-Birkenbach
8409843ff9
The dump replay ran statement-by-statement with autocommit. When restore --empty runs against a LIVE database, the pre-clean drops a table, the replay recreates it and autocommits, and a concurrent writer (discourse's mini_scheduler upserting scheduler_stats(id=1)) inserts the same primary key into the empty table before the dump's COPY loads it. The COPY then aborts with a duplicate-key violation under ON_ERROR_STOP and the whole restore fails. Running the replay with --single-transaction keeps the recreated table invisible to other sessions until commit, so the writer can never insert the racing row. The --empty pre-clean stays multi-statement (\gexec, one DROP per statement): running every DROP in one transaction exhausts max_locks_per_transaction on large schemas (e.g. gitlab). Extract the pre-clean SQL from the inline string into restore/db/empty_preclean.sql (loaded via dirname(__file__)) and declare it as package-data so it ships in the wheel. Add a unit test guarding the single-transaction/multi-statement split and an e2e that reproduces the live-writer race. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
65 lines
3.2 KiB
SQL
65 lines
3.2 KiB
SQL
-- Owner-filtered pre-clean for `restore --empty`. Emitted as one DROP per row and
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-- run via \gexec so each executes as its own top-level statement: a single DO-block
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-- would run every DROP in one transaction and exhaust max_locks_per_transaction on
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-- large schemas (e.g. gitlab). Also drops user-owned non-public schemas so a dump
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-- that CREATE SCHEMAs (e.g. discourse's discourse_functions) does not fail on an
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-- already-existing schema. Extension members (pg_trgm's set_limit) are
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-- superuser-owned; IF EXISTS absorbs the CASCADE fallout.
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SELECT format('DROP %s IF EXISTS public.%s CASCADE', obj.type, obj.name)
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FROM (
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SELECT format('%I', c.relname) AS name,
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CASE c.relkind
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WHEN 'v' THEN 'VIEW'
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WHEN 'm' THEN 'MATERIALIZED VIEW'
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WHEN 'f' THEN 'FOREIGN TABLE'
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ELSE 'TABLE'
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END AS type
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FROM pg_class c JOIN pg_namespace n ON n.oid = c.relnamespace
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WHERE n.nspname = 'public' AND c.relkind IN ('r', 'p', 'v', 'm', 'f')
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AND pg_get_userbyid(c.relowner) = current_user
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UNION ALL
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-- Overloaded functions share a proname; DROP needs the identity
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-- signature or psql aborts with "function name is not unique".
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SELECT format('%I(%s)', p.proname, pg_get_function_identity_arguments(p.oid)) AS name,
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CASE p.prokind WHEN 'p' THEN 'PROCEDURE' ELSE 'FUNCTION' END AS type
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FROM pg_proc p JOIN pg_namespace n ON n.oid = p.pronamespace
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WHERE n.nspname = 'public' AND p.prokind IN ('f', 'p', 'w')
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AND pg_get_userbyid(p.proowner) = current_user
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UNION ALL
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SELECT format('%I', c.relname) AS name, 'SEQUENCE' AS type
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FROM pg_class c JOIN pg_namespace n ON n.oid = c.relnamespace
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WHERE n.nspname = 'public' AND c.relkind = 'S'
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AND pg_get_userbyid(c.relowner) = current_user
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UNION ALL
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SELECT format('%I', t.typname) AS name, 'TYPE' AS type
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FROM pg_type t JOIN pg_namespace n ON n.oid = t.typnamespace
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WHERE n.nspname = 'public'
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AND pg_get_userbyid(t.typowner) = current_user
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AND (t.typtype IN ('e', 'd')
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OR (t.typtype = 'c' AND EXISTS (
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SELECT 1 FROM pg_class c2
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WHERE c2.oid = t.typrelid AND c2.relkind = 'c')))
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UNION ALL
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SELECT format('%I', col.collname) AS name, 'COLLATION' AS type
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FROM pg_collation col JOIN pg_namespace n ON n.oid = col.collnamespace
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WHERE n.nspname = 'public'
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AND pg_get_userbyid(col.collowner) = current_user
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UNION ALL
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SELECT format('%I', ts.cfgname) AS name, 'TEXT SEARCH CONFIGURATION' AS type
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FROM pg_ts_config ts JOIN pg_namespace n ON n.oid = ts.cfgnamespace
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WHERE n.nspname = 'public'
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AND pg_get_userbyid(ts.cfgowner) = current_user
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UNION ALL
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SELECT format('%I', d.dictname) AS name, 'TEXT SEARCH DICTIONARY' AS type
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FROM pg_ts_dict d JOIN pg_namespace n ON n.oid = d.dictnamespace
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WHERE n.nspname = 'public'
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AND pg_get_userbyid(d.dictowner) = current_user
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) obj
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UNION ALL
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SELECT format('DROP SCHEMA IF EXISTS %I CASCADE', n.nspname)
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FROM pg_namespace n
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WHERE NOT starts_with(n.nspname, 'pg_')
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AND n.nspname NOT IN ('public', 'information_schema')
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AND pg_get_userbyid(n.nspowner) = current_user
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\gexec
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