/*
 * pg_repack: lib/pg_repack.sql.in
 *
 * Portions Copyright (c) 2008-2011, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
 * Portions Copyright (c) 2011, Itagaki Takahiro
 * Portions Copyright (c) 2012, The Reorg Development Team
 */

CREATE SCHEMA repack;

CREATE FUNCTION repack.version() RETURNS text AS
'MODULE_PATHNAME', 'repack_version'
LANGUAGE C IMMUTABLE STRICT;

CREATE FUNCTION repack.version_sql() RETURNS text AS
$$SELECT 'pg_repack EXTVER'::text$$
LANGUAGE SQL IMMUTABLE STRICT;

CREATE AGGREGATE repack.array_accum (
    sfunc = array_append,
    basetype = anyelement,
    stype = anyarray,
    initcond = '{}'
);

CREATE FUNCTION repack.oid2text(oid) RETURNS text AS
$$
	SELECT textin(regclassout($1));
$$
LANGUAGE sql STABLE STRICT;

CREATE FUNCTION repack.get_index_columns(oid, text) RETURNS text AS
$$
  SELECT array_to_string(repack.array_accum(quote_ident(attname)), $2)
    FROM pg_attribute,
         (SELECT indrelid,
                 indkey,
                 generate_series(0, indnatts-1) AS i
            FROM pg_index
           WHERE indexrelid = $1
         ) AS keys
   WHERE attrelid = indrelid
     AND attnum = indkey[i];
$$
LANGUAGE sql STABLE STRICT;

CREATE FUNCTION repack.get_index_keys(oid, oid) RETURNS text AS
'MODULE_PATHNAME', 'repack_get_index_keys'
LANGUAGE C STABLE STRICT;

CREATE FUNCTION repack.get_create_index_type(oid, name) RETURNS text AS
$$
  SELECT 'CREATE TYPE ' || $2 || ' AS (' ||
         array_to_string(repack.array_accum(quote_ident(attname) || ' ' ||
           pg_catalog.format_type(atttypid, atttypmod)), ', ') || ')'
    FROM pg_attribute,
         (SELECT indrelid,
                 indkey,
                 generate_series(0, indnatts-1) AS i
            FROM pg_index
           WHERE indexrelid = $1
         ) AS keys
   WHERE attrelid = indrelid
     AND attnum = indkey[i];
$$
LANGUAGE sql STABLE STRICT;

CREATE FUNCTION repack.get_create_trigger(relid oid, pkid oid)
  RETURNS text AS
$$
  SELECT 'CREATE TRIGGER z_repack_trigger' ||
         ' BEFORE INSERT OR DELETE OR UPDATE ON ' || repack.oid2text($1) ||
         ' FOR EACH ROW EXECUTE PROCEDURE repack.repack_trigger(' ||
         '''INSERT INTO repack.log_' || $1 || '(pk, row) VALUES(' ||
         ' CASE WHEN $1 IS NULL THEN NULL ELSE (ROW($1.' ||
         repack.get_index_columns($2, ', $1.') || ')::repack.pk_' ||
         $1 || ') END, $2)'')';
$$
LANGUAGE sql STABLE STRICT;

CREATE FUNCTION repack.get_enable_trigger(relid oid)
  RETURNS text AS
$$
  SELECT 'ALTER TABLE ' || repack.oid2text($1) ||
    ' ENABLE ALWAYS TRIGGER z_repack_trigger';
$$
LANGUAGE sql STABLE STRICT;

CREATE FUNCTION repack.get_assign(oid, text) RETURNS text AS
$$
  SELECT '(' || array_to_string(repack.array_accum(quote_ident(attname)), ', ') ||
         ') = (' || $2 || '.' ||
         array_to_string(repack.array_accum(quote_ident(attname)), ', ' || $2 || '.') || ')'
    FROM (SELECT attname FROM pg_attribute
           WHERE attrelid = $1 AND attnum > 0 AND NOT attisdropped
           ORDER BY attnum) tmp;
$$
LANGUAGE sql STABLE STRICT;

CREATE FUNCTION repack.get_compare_pkey(oid, text)
  RETURNS text AS
$$
  SELECT '(' || array_to_string(repack.array_accum(quote_ident(attname)), ', ') ||
         ') = (' || $2 || '.' ||
         array_to_string(repack.array_accum(quote_ident(attname)), ', ' || $2 || '.') || ')'
    FROM pg_attribute,
         (SELECT indrelid,
                 indkey,
                 generate_series(0, indnatts-1) AS i
            FROM pg_index
           WHERE indexrelid = $1
         ) AS keys
   WHERE attrelid = indrelid
     AND attnum = indkey[i];
$$
LANGUAGE sql STABLE STRICT;

-- Get a column list for SELECT all columns including dropped ones.
-- We use NULLs of integer types for dropped columns (types are not important).
CREATE FUNCTION repack.get_columns_for_create_as(oid)
  RETURNS text AS
$$
SELECT array_to_string(repack.array_accum(c), ',') FROM (SELECT
	CASE WHEN attisdropped
		THEN 'NULL::integer AS ' || quote_ident(attname)
		ELSE quote_ident(attname)
	END AS c
FROM pg_attribute
WHERE attrelid = $1 AND attnum > 0 ORDER BY attnum
) AS COL
$$
LANGUAGE sql STABLE STRICT;

-- Get a SQL text to DROP dropped columns for the table,
-- or NULL if it has no dropped columns.
CREATE FUNCTION repack.get_drop_columns(oid, text)
  RETURNS text AS
$$
SELECT
	'ALTER TABLE ' || $2 || ' ' || array_to_string(dropped_columns, ', ')
FROM (
	SELECT
		repack.array_accum('DROP COLUMN ' || quote_ident(attname)) AS dropped_columns
	FROM (
		SELECT * FROM pg_attribute
		WHERE attrelid = $1 AND attnum > 0 AND attisdropped
		ORDER BY attnum
	) T
) T
WHERE
	array_upper(dropped_columns, 1) > 0
$$
LANGUAGE sql STABLE STRICT;

-- includes not only PRIMARY KEYS but also UNIQUE NOT NULL keys
CREATE VIEW repack.primary_keys AS
  SELECT indrelid, (repack.array_accum(indexrelid))[1] AS indexrelid
    FROM (SELECT indrelid, indexrelid FROM pg_index
   WHERE indisunique
     AND indisvalid
     AND indpred IS NULL
     AND 0 <> ALL(indkey)
     AND NOT EXISTS(
           SELECT 1 FROM pg_attribute
            WHERE attrelid = indrelid
              AND attnum = ANY(indkey)
              AND NOT attnotnull)
   ORDER BY indrelid, indisprimary DESC, indnatts, indkey) tmp
   GROUP BY indrelid;

CREATE VIEW repack.tables AS
  SELECT R.oid::regclass AS relname,
         R.oid AS relid,
         R.reltoastrelid AS reltoastrelid,
         CASE WHEN R.reltoastrelid = 0 THEN 0 ELSE (SELECT reltoastidxid FROM pg_class WHERE oid = R.reltoastrelid) END AS reltoastidxid,
         PK.indexrelid AS pkid,
         CK.indexrelid AS ckid,
         repack.get_create_index_type(PK.indexrelid, 'repack.pk_' || R.oid) AS create_pktype,
         'CREATE TABLE repack.log_' || R.oid || ' (id bigserial PRIMARY KEY, pk repack.pk_' || R.oid || ', row ' || repack.oid2text(R.oid) || ')' AS create_log,
         repack.get_create_trigger(R.oid, PK.indexrelid) AS create_trigger,
         repack.get_enable_trigger(R.oid) as enable_trigger,
         'CREATE TABLE repack.table_' || R.oid || ' WITH (' || array_to_string(array_append(R.reloptions, 'oids=' || CASE WHEN R.relhasoids THEN 'true' ELSE 'false' END), ',') || ') TABLESPACE ' || coalesce(quote_ident(S.spcname), 'pg_default') || ' AS SELECT ' || repack.get_columns_for_create_as(R.oid) || ' FROM ONLY ' || repack.oid2text(R.oid) AS create_table,
         repack.get_drop_columns(R.oid, 'repack.table_' || R.oid) AS drop_columns,
         'DELETE FROM repack.log_' || R.oid AS delete_log,
         'LOCK TABLE ' || repack.oid2text(R.oid) || ' IN ACCESS EXCLUSIVE MODE' AS lock_table,
         repack.get_index_keys(CK.indexrelid, R.oid) AS ckey,
         'SELECT * FROM repack.log_' || R.oid || ' ORDER BY id LIMIT $1' AS sql_peek,
         'INSERT INTO repack.table_' || R.oid || ' VALUES ($1.*)' AS sql_insert,
         'DELETE FROM repack.table_' || R.oid || ' WHERE ' || repack.get_compare_pkey(PK.indexrelid, '$1') AS sql_delete,
         'UPDATE repack.table_' || R.oid || ' SET ' || repack.get_assign(R.oid, '$2') || ' WHERE ' || repack.get_compare_pkey(PK.indexrelid, '$1') AS sql_update,
         'DELETE FROM repack.log_' || R.oid || ' WHERE id <= $1' AS sql_pop
    FROM pg_class R
         LEFT JOIN pg_class T ON R.reltoastrelid = T.oid
         LEFT JOIN repack.primary_keys PK
                ON R.oid = PK.indrelid
         LEFT JOIN (SELECT CKI.* FROM pg_index CKI, pg_class CKT
                     WHERE CKI.indisvalid
                       AND CKI.indexrelid = CKT.oid
                       AND CKI.indisclustered
                       AND CKT.relam = 403) CK
                ON R.oid = CK.indrelid
         LEFT JOIN pg_namespace N ON N.oid = R.relnamespace
         LEFT JOIN pg_tablespace S ON S.oid = R.reltablespace
   WHERE R.relkind = 'r'
     AND N.nspname NOT IN ('pg_catalog', 'information_schema')
     AND N.nspname NOT LIKE E'pg\\_temp\\_%';

CREATE FUNCTION repack.repack_indexdef(oid, oid) RETURNS text AS
'MODULE_PATHNAME', 'repack_indexdef'
LANGUAGE C STABLE STRICT;

CREATE FUNCTION repack.repack_trigger() RETURNS trigger AS
'MODULE_PATHNAME', 'repack_trigger'
LANGUAGE C VOLATILE STRICT SECURITY DEFINER;

CREATE FUNCTION repack.conflicted_triggers(oid) RETURNS SETOF name AS
$$
SELECT tgname FROM pg_trigger
 WHERE tgrelid = $1 AND tgname >= 'z_repack_trigger'
$$
LANGUAGE sql STABLE STRICT;

CREATE FUNCTION repack.disable_autovacuum(regclass) RETURNS void AS
'MODULE_PATHNAME', 'repack_disable_autovacuum'
LANGUAGE C VOLATILE STRICT;

CREATE FUNCTION repack.repack_apply(
  sql_peek      cstring,
  sql_insert    cstring,
  sql_delete    cstring,
  sql_update    cstring,
  sql_pop       cstring,
  count         integer)
RETURNS integer AS
'MODULE_PATHNAME', 'repack_apply'
LANGUAGE C VOLATILE;

CREATE FUNCTION repack.repack_swap(oid) RETURNS void AS
'MODULE_PATHNAME', 'repack_swap'
LANGUAGE C VOLATILE STRICT;

CREATE FUNCTION repack.repack_drop(oid) RETURNS void AS
'MODULE_PATHNAME', 'repack_drop'
LANGUAGE C VOLATILE STRICT;