cartodb-postgresql/scripts-available/CDB_QueryTables.sql
2016-02-08 19:29:14 +01:00

128 lines
3.8 KiB
PL/PgSQL

-- Return an array of table names scanned by a given query
--
-- Requires PostgreSQL 9.x+
--
CREATE OR REPLACE FUNCTION CDB_QueryTablesText(query text)
RETURNS text[]
AS $$
DECLARE
exp XML;
tables text[];
rec RECORD;
rec2 RECORD;
BEGIN
tables := '{}';
FOR rec IN SELECT CDB_QueryStatements(query) q LOOP
IF NOT ( rec.q ilike 'select%' or rec.q ilike 'with%' ) THEN
--RAISE WARNING 'Skipping %', rec.q;
CONTINUE;
END IF;
BEGIN
EXECUTE 'EXPLAIN (FORMAT XML, VERBOSE) ' || rec.q INTO STRICT exp;
EXCEPTION WHEN others THEN
-- TODO: if error is 'relation "xxxxxx" does not exist', take xxxxxx as
-- the affected table ?
RAISE WARNING 'CDB_QueryTables cannot explain query: % (%: %)', rec.q, SQLSTATE, SQLERRM;
RAISE EXCEPTION '%', SQLERRM;
CONTINUE;
END;
-- Now need to extract all values of <Relation-Name>
-- RAISE DEBUG 'Explain: %', exp;
FOR rec2 IN WITH
inp AS (
SELECT
xpath('//x:Relation-Name/text()', exp, ARRAY[ARRAY['x', 'http://www.postgresql.org/2009/explain']]) as x,
xpath('//x:Relation-Name/../x:Schema/text()', exp, ARRAY[ARRAY['x', 'http://www.postgresql.org/2009/explain']]) as s
)
SELECT unnest(x)::text as p, unnest(s)::text as sc from inp
LOOP
-- RAISE DEBUG 'tab: %', rec2.p;
-- RAISE DEBUG 'sc: %', rec2.sc;
tables := array_append(tables, format('%s.%s', quote_ident(rec2.sc), quote_ident(rec2.p)));
END LOOP;
-- RAISE DEBUG 'Tables: %', tables;
END LOOP;
-- RAISE DEBUG 'Tables: %', tables;
-- Remove duplicates and sort by name
IF array_upper(tables, 1) > 0 THEN
WITH dist as ( SELECT DISTINCT unnest(tables)::text as p ORDER BY p )
SELECT array_agg(p) from dist into tables;
END IF;
--RAISE DEBUG 'Tables: %', tables;
return tables;
END
$$ LANGUAGE 'plpgsql' VOLATILE STRICT;
-- Keep CDB_QueryTables with same signature for backwards compatibility.
-- It should probably be removed in the future.
CREATE OR REPLACE FUNCTION CDB_QueryTables(query text)
RETURNS name[]
AS $$
BEGIN
RETURN CDB_QueryTablesText(query)::name[];
END
$$ LANGUAGE 'plpgsql' VOLATILE STRICT;
--------------------------------------------------------------------------------
-- Return a set of {dbname, schema_name, table_name. updated_at}
CREATE OR REPLACE FUNCTION CDB_QueryTablesUpdatedAt(query text)
RETURNS TABLE(db_name text, schema_name text, table_name text, updated_at timestamptz)
AS $$
BEGIN
RETURN QUERY
WITH query_tables AS (
SELECT unnest(CDB_QueryTablesText(query)) schema_table_name
), query_tables_oid AS (
SELECT schema_table_name, schema_table_name::regclass::oid AS reloid
FROM query_tables
),
fqtn AS (
SELECT
(CASE WHEN c.relkind = 'f' THEN _cdb_dbname_of_foreign_table(query_tables_oid.reloid)
ELSE current_database()
END)::text AS dbname,
n.nspname::text schema_name,
c.relname::text table_name,
c.relkind,
query_tables_oid.reloid
FROM query_tables_oid, pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid
WHERE c.oid = query_tables_oid.reloid
)
SELECT fqtn.dbname, fqtn.schema_name, fqtn.table_name,
(CASE WHEN relkind = 'f' THEN CDB_Get_Foreign_Updated_At(reloid)
ELSE (SELECT md.updated_at FROM CDB_TableMetadata md WHERE tabname = reloid)
END) AS updated_at
FROM fqtn;
END
$$ LANGUAGE 'plpgsql' VOLATILE STRICT;
CREATE OR REPLACE FUNCTION _cdb_dbname_of_foreign_table(reloid oid)
RETURNS TEXT AS $$
SELECT option_value FROM pg_options_to_table((
SELECT fs.srvoptions
FROM pg_foreign_table ft
LEFT JOIN pg_foreign_server fs ON ft.ftserver = fs.oid
WHERE ft.ftrelid = reloid
)) WHERE option_name='dbname';
$$ LANGUAGE SQL;