cartodb-postgresql/scripts-available/CDB_ForeignTable.sql
2019-05-31 15:37:15 +02:00

200 lines
8.3 KiB
PL/PgSQL

---------------------------
-- FDW MANAGEMENT FUNCTIONS
--
-- All the FDW settings are read from the `cdb_conf.fdws` entry json file.
---------------------------
CREATE OR REPLACE FUNCTION @extschema@._CDB_Setup_FDW(fdw_name text, config json)
RETURNS void
AS $$
DECLARE
row record;
option record;
org_role text;
BEGIN
-- This function tries to be as idempotent as possible, by not creating anything more than once
-- (not even using IF NOT EXIST to avoid throwing warnings)
IF NOT EXISTS ( SELECT * FROM pg_extension WHERE extname = 'postgres_fdw') THEN
CREATE EXTENSION postgres_fdw;
END IF;
-- Create FDW first if it does not exist
IF NOT EXISTS ( SELECT * FROM pg_foreign_server WHERE srvname = fdw_name)
THEN
EXECUTE FORMAT('CREATE SERVER %I FOREIGN DATA WRAPPER postgres_fdw', fdw_name);
END IF;
-- Set FDW settings
FOR row IN SELECT p.key, p.value from lateral json_each_text(config->'server') p
LOOP
IF NOT EXISTS (WITH a AS (select split_part(unnest(srvoptions), '=', 1) as options from pg_foreign_server where srvname=fdw_name) SELECT * from a where options = row.key)
THEN
EXECUTE FORMAT('ALTER SERVER %I OPTIONS (ADD %I %L)', fdw_name, row.key, row.value);
ELSE
EXECUTE FORMAT('ALTER SERVER %I OPTIONS (SET %I %L)', fdw_name, row.key, row.value);
END IF;
END LOOP;
-- Create user mappings
FOR row IN SELECT p.key, p.value from lateral json_each(config->'users') p LOOP
-- Check if entry on pg_user_mappings exists
IF NOT EXISTS ( SELECT * FROM pg_user_mappings WHERE srvname = fdw_name AND usename = row.key ) THEN
EXECUTE FORMAT ('CREATE USER MAPPING FOR %I SERVER %I', row.key, fdw_name);
END IF;
-- Update user mapping settings
FOR option IN SELECT o.key, o.value from lateral json_each_text(row.value) o LOOP
IF NOT EXISTS (WITH a AS (select split_part(unnest(umoptions), '=', 1) as options from pg_user_mappings WHERE srvname = fdw_name AND usename = row.key) SELECT * from a where options = option.key) THEN
EXECUTE FORMAT('ALTER USER MAPPING FOR %I SERVER %I OPTIONS (ADD %I %L)', row.key, fdw_name, option.key, option.value);
ELSE
EXECUTE FORMAT('ALTER USER MAPPING FOR %I SERVER %I OPTIONS (SET %I %L)', row.key, fdw_name, option.key, option.value);
END IF;
END LOOP;
END LOOP;
-- Create schema if it does not exist.
IF NOT EXISTS ( SELECT * from pg_namespace WHERE nspname=fdw_name) THEN
EXECUTE FORMAT ('CREATE SCHEMA %I', fdw_name);
END IF;
-- Give the organization role usage permisions over the schema
SELECT @extschema@.CDB_Organization_Member_Group_Role_Member_Name() INTO org_role;
EXECUTE FORMAT ('GRANT USAGE ON SCHEMA %I TO %I', fdw_name, org_role);
-- Bring here the remote cdb_tablemetadata
IF NOT EXISTS ( SELECT * FROM PG_CLASS WHERE relnamespace = (SELECT oid FROM pg_namespace WHERE nspname=fdw_name) and relname='cdb_tablemetadata') THEN
EXECUTE FORMAT ('CREATE FOREIGN TABLE %I.cdb_tablemetadata (tabname text, updated_at timestamp with time zone) SERVER %I OPTIONS (table_name ''cdb_tablemetadata_text'', schema_name ''@extschema@'', updatable ''false'')', fdw_name, fdw_name);
END IF;
EXECUTE FORMAT ('GRANT SELECT ON %I.cdb_tablemetadata TO %I', fdw_name, org_role);
END
$$
LANGUAGE PLPGSQL VOLATILE PARALLEL UNSAFE;
CREATE OR REPLACE FUNCTION @extschema@._CDB_Setup_FDWS()
RETURNS VOID AS
$$
DECLARE
row record;
BEGIN
FOR row IN SELECT p.key, p.value from lateral json_each(@extschema@.CDB_Conf_GetConf('fdws')) p LOOP
EXECUTE 'SELECT @extschema@._CDB_Setup_FDW($1, $2)' USING row.key, row.value;
END LOOP;
END
$$
LANGUAGE PLPGSQL VOLATILE PARALLEL UNSAFE;
CREATE OR REPLACE FUNCTION @extschema@._CDB_Setup_FDW(fdw_name text)
RETURNS void AS
$BODY$
DECLARE
config json;
BEGIN
SELECT p.value FROM LATERAL json_each(@extschema@.CDB_Conf_GetConf('fdws')) p WHERE p.key = fdw_name INTO config;
EXECUTE 'SELECT @extschema@._CDB_Setup_FDW($1, $2)' USING fdw_name, config;
END
$BODY$
LANGUAGE plpgsql VOLATILE PARALLEL UNSAFE;
CREATE OR REPLACE FUNCTION @extschema@.CDB_Add_Remote_Table(source text, table_name text)
RETURNS void AS
$$
BEGIN
PERFORM @extschema@._CDB_Setup_FDW(source);
EXECUTE FORMAT ('IMPORT FOREIGN SCHEMA %I LIMIT TO (%I) FROM SERVER %I INTO %I;', source, table_name, source, source);
--- Grant SELECT to publicuser
EXECUTE FORMAT ('GRANT SELECT ON %I.%I TO publicuser;', source, table_name);
END
$$
LANGUAGE plpgsql VOLATILE PARALLEL UNSAFE;
CREATE OR REPLACE FUNCTION @extschema@.CDB_Get_Foreign_Updated_At(foreign_table regclass)
RETURNS timestamp with time zone AS
$$
DECLARE
remote_table_name text;
fdw_schema_name text;
time timestamp with time zone;
BEGIN
-- This will turn a local foreign table (referenced as regclass) to its fully qualified text remote table reference.
WITH a AS (SELECT ftoptions FROM pg_foreign_table WHERE ftrelid=foreign_table LIMIT 1),
b as (SELECT (pg_options_to_table(ftoptions)).* FROM a)
SELECT FORMAT('%I.%I', (SELECT option_value FROM b WHERE option_name='schema_name'), (SELECT option_value FROM b WHERE option_name='table_name'))
INTO remote_table_name;
-- We assume that the remote cdb_tablemetadata is called cdb_tablemetadata and is on the same schema as the queried table.
SELECT nspname FROM pg_class c, pg_namespace n WHERE c.oid=foreign_table AND c.relnamespace = n.oid INTO fdw_schema_name;
EXECUTE FORMAT('SELECT updated_at FROM %I.cdb_tablemetadata WHERE tabname=%L ORDER BY updated_at DESC LIMIT 1', fdw_schema_name, remote_table_name) INTO time;
RETURN time;
END
$$
LANGUAGE plpgsql VOLATILE PARALLEL UNSAFE;
CREATE OR REPLACE FUNCTION @extschema@._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 VOLATILE PARALLEL UNSAFE;
-- Return a set of (dbname, schema_name, table_name, updated_at)
-- It is aware of foreign tables
-- It assumes the local (schema_name, table_name) map to the remote ones with the same name
-- Note: dbname is never quoted whereas schema and table names are when needed.
CREATE OR REPLACE FUNCTION @extschema@.CDB_QueryTables_Updated_At(query text)
RETURNS TABLE(dbname text, schema_name text, table_name text, updated_at timestamptz)
AS $$
WITH query_tables AS (
SELECT unnest(@extschema@.CDB_QueryTablesText(query)) schema_table_name
), query_tables_oid AS (
SELECT schema_table_name, schema_table_name::regclass::oid AS reloid
FROM query_tables
),
fqtn AS (
SELECT
(CASE WHEN c.relkind = 'f' THEN @extschema@._cdb_dbname_of_foreign_table(query_tables_oid.reloid)
ELSE current_database()
END)::text AS dbname,
quote_ident(n.nspname::text) schema_name,
quote_ident(c.relname::text) table_name,
c.relkind,
query_tables_oid.reloid
FROM query_tables_oid, pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON c.relnamespace = n.oid
WHERE c.oid = query_tables_oid.reloid
)
SELECT fqtn.dbname, fqtn.schema_name, fqtn.table_name,
(CASE WHEN relkind = 'f' THEN @extschema@.CDB_Get_Foreign_Updated_At(reloid)
ELSE (SELECT md.updated_at FROM @extschema@.CDB_TableMetadata md WHERE md.tabname = reloid)
END) AS updated_at
FROM fqtn;
$$ LANGUAGE SQL VOLATILE PARALLEL UNSAFE;
-- Return the last updated time of a set of tables
-- It is aware of foreign tables
-- It assumes the local (schema_name, table_name) map to the remote ones with the same name
CREATE OR REPLACE FUNCTION @extschema@.CDB_Last_Updated_Time(tables text[])
RETURNS timestamptz AS $$
WITH t AS (
SELECT unnest(tables) AS schema_table_name
), t_oid AS (
SELECT (t.schema_table_name)::regclass::oid as reloid FROM t
), t_updated_at AS (
SELECT
(CASE WHEN relkind = 'f' THEN @extschema@.CDB_Get_Foreign_Updated_At(reloid)
ELSE (SELECT md.updated_at FROM @extschema@.CDB_TableMetadata md WHERE md.tabname = reloid)
END) AS updated_at
FROM t_oid
LEFT JOIN pg_catalog.pg_class c ON c.oid = reloid
) SELECT max(updated_at) FROM t_updated_at;
$$ LANGUAGE SQL VOLATILE PARALLEL UNSAFE;