76 lines
2.2 KiB
PL/PgSQL
76 lines
2.2 KiB
PL/PgSQL
-- Return an array of table names scanned by a given query
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--
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-- Requires PostgreSQL 9.x+
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--
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CREATE OR REPLACE FUNCTION CDB_QueryTablesText(query text)
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RETURNS text[]
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AS $$
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DECLARE
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exp XML;
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tables text[];
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rec RECORD;
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rec2 RECORD;
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BEGIN
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tables := '{}';
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FOR rec IN SELECT CDB_QueryStatements(query) q LOOP
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BEGIN
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EXECUTE 'EXPLAIN (FORMAT XML, VERBOSE) ' || rec.q INTO STRICT exp;
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EXCEPTION WHEN syntax_error THEN
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-- We can get a syntax error if the user tries to EXPLAIN a DDL
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CONTINUE;
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WHEN others THEN
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-- TODO: if error is 'relation "xxxxxx" does not exist', take xxxxxx as
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-- the affected table ?
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RAISE WARNING 'CDB_QueryTables cannot explain query: % (%: %)', rec.q, SQLSTATE, SQLERRM;
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RAISE EXCEPTION '%', SQLERRM;
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CONTINUE;
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END;
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-- Now need to extract all values of <Relation-Name>
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-- RAISE DEBUG 'Explain: %', exp;
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FOR rec2 IN WITH
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inp AS (
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SELECT
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xpath('//x:Relation-Name/text()', exp, ARRAY[ARRAY['x', 'http://www.postgresql.org/2009/explain']]) as x,
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xpath('//x:Relation-Name/../x:Schema/text()', exp, ARRAY[ARRAY['x', 'http://www.postgresql.org/2009/explain']]) as s
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)
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SELECT unnest(x)::text as p, unnest(s)::text as sc from inp
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LOOP
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-- RAISE DEBUG 'tab: %', rec2.p;
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-- RAISE DEBUG 'sc: %', rec2.sc;
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tables := array_append(tables, format('%s.%s', quote_ident(rec2.sc), quote_ident(rec2.p)));
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END LOOP;
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-- RAISE DEBUG 'Tables: %', tables;
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END LOOP;
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-- RAISE DEBUG 'Tables: %', tables;
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-- Remove duplicates and sort by name
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IF array_upper(tables, 1) > 0 THEN
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WITH dist as ( SELECT DISTINCT unnest(tables)::text as p ORDER BY p )
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SELECT array_agg(p) from dist into tables;
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END IF;
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--RAISE DEBUG 'Tables: %', tables;
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return tables;
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END
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$$ LANGUAGE 'plpgsql' VOLATILE STRICT PARALLEL UNSAFE;
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-- Keep CDB_QueryTables with same signature for backwards compatibility.
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-- It should probably be removed in the future.
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CREATE OR REPLACE FUNCTION CDB_QueryTables(query text)
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RETURNS name[]
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AS $$
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BEGIN
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RETURN CDB_QueryTablesText(query)::name[];
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END
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$$ LANGUAGE 'plpgsql' VOLATILE STRICT PARALLEL UNSAFE;
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