Sectioning: Shot and Forgot

CREATE OR REPLACE FUNCTION to_timestamp(timestamp without time zone) RETURNS timestamp with time zone AS $_$
  select $1::timestamp with time zone;
$_$ LANGUAGE sql STABLE STRICT;
CREATE OR REPLACE FUNCTION to_timestamp(timestamp with time zone) RETURNS timestamp with time zone AS $_$
  select $1::timestamp with time zone;
$_$ LANGUAGE sql STABLE STRICT;
CREATE OR REPLACE FUNCTION to_numeric(text) RETURNS numeric AS $_$
  select regexp_replace($1, '\D+', '', 'g')::numeric;
$_$ LANGUAGE sql STABLE STRICT;
CREATE OR REPLACE FUNCTION copy_constraints(srcoid oid, dstoid oid)
  RETURNS integer AS
$BODY$
declare
  i int4 := 0;
  constrs record;
  srctable text;
  dsttable text;
begin
  srctable = srcoid::regclass;
  dsttable = dstoid::regclass;
  for constrs in
  select conname as name, pg_get_constraintdef(oid) as definition
  from pg_constraint where conrelid = srcoid loop
    begin
    execute 'alter table ' || dsttable
      || ' add constraint '
      || replace(replace(constrs.name, srctable, dsttable),'.','_')
      || ' ' || constrs.definition;
    i = i + 1;
    exception
      when duplicate_table then
    end;
  end loop;
  return i;
exception when undefined_table then
  return null;
end;
$BODY$
LANGUAGE 'plpgsql' VOLATILE;
CREATE OR REPLACE FUNCTION copy_constraints(src text, dst text)
  RETURNS integer AS
$BODY$
begin
  return copy_constraints(src::regclass::oid, dst::regclass::oid);
end;
$BODY$
LANGUAGE 'plpgsql' IMMUTABLE;
CREATE OR REPLACE FUNCTION copy_indexes(srcoid oid, dstoid oid)
  RETURNS integer AS
$BODY$
declare
  i int4 := 0;
  indexes record;
  srctable text;
  dsttable text;
  script text;
begin
  srctable = srcoid::regclass;
  dsttable = dstoid::regclass;
  for indexes in
  select c.relname as name, pg_get_indexdef(idx.indexrelid) as definition
  from pg_index idx, pg_class c where idx.indrelid = srcoid and c.oid = idx.indexrelid loop
    script = replace (indexes.definition, ' INDEX '
      || indexes.name, ' INDEX '
      || replace(replace(indexes.name, srctable, dsttable),'.','_'));
    script = replace (script, ' ON ' || srctable, ' ON ' || dsttable);
    begin
      execute script;
      i = i + 1;
    exception
      when duplicate_table then
    end;
  end loop;
  return i;
exception when undefined_table then
  return null;
end;
$BODY$
LANGUAGE 'plpgsql' VOLATILE;
CREATE OR REPLACE FUNCTION copy_indexes(src text, dst text)
  RETURNS integer AS
$BODY$
begin
  return copy_indexes(src::regclass::oid, dst::regclass::oid);
end;
$BODY$
LANGUAGE 'plpgsql' IMMUTABLE;
CREATE OR REPLACE FUNCTION copy_triggers(srcoid oid, dstoid oid)
  RETURNS integer AS
$BODY$
declare
  i int4 := 0;
  triggers record;
  srctable text;
  dsttable text;
  script text = '';
begin
  srctable = srcoid::regclass;
  dsttable = dstoid::regclass;
  for triggers in
   select tgname as name, pg_get_triggerdef(oid) as definition
   from pg_trigger where tgrelid = srcoid loop
    script =
    replace (triggers.definition, ' TRIGGER '
      || triggers.name, ' TRIGGER '
      || replace(replace(triggers.name, srctable, dsttable),'.','_'));
    script = replace (script, ' ON ' || srctable, ' ON ' || dsttable);
    begin
      execute script;
      i = i + 1;
    exception
      when duplicate_table then
    end;
  end loop;
  return i;
exception when undefined_table then
  return null;
end;
$BODY$
LANGUAGE 'plpgsql' VOLATILE;
CREATE OR REPLACE FUNCTION copy_triggers(src text, dst text)
  RETURNS integer AS
$BODY$
begin
  return copy_triggers(src::regclass::oid, dst::regclass::oid);
end;
$BODY$
LANGUAGE 'plpgsql' IMMUTABLE;

CREATE OR REPLACE FUNCTION "create_partition" (in tbl varchar, in method varchar, in params varchar, in sample text) RETURNS text AS $BODY$
declare
  scheme varchar := split_part(tbl, '.', 1);
  parent varchar := split_part(tbl, '.', 2);
  field varchar := split_part(tbl, '.', 3);
  child  varchar;
  script text;
  trig text;
  part text[];
begin
    execute 'select partition_'||method||'('''||params||''', '''||field||''', '''||sample||''')' into part;
    -- RAISE EXCEPTION 'part %', part;
    child = scheme || '.' || parent || '_' || (part[1]::text);
    execute 'create table IF NOT EXISTS ' || child || '
    (
     constraint partition_' || (part[1]) || ' check '
      || (part[2]) || '
    )
    inherits (' || parent || ')';
    perform copy_constraints(parent, child);
    perform copy_indexes(parent, child);
    -- execute 'GRANT SELECT ON ' || child || ' TO some_other_user';
    -- execute 'GRANT ALL ON ' || child || ' TO user';
    script = (select string_agg(c, chr(10)||'        ELS') from (
        select to_numeric(replace(t.table_name, parent||'_','')) as n, 'IF '||replace(left(right(cc.check_clause, -1), -1), c.column_name, 'NEW.'||c.column_name)||' THEN INSERT INTO '||t.table_schema||'.'||t.table_name||' VALUES (NEW.*);' as c
          from information_schema.TABLE_CONSTRAINTS t
                  join information_schema.CONSTRAINT_COLUMN_USAGE c
            ON t.constraint_name = c.constraint_name
                  join information_schema.check_constraints cc
            ON t.constraint_name = cc.constraint_name
          where constraint_type IN ('CHECK')
                  and t.table_name like parent||'\_%'
          group by t.table_schema, t.table_name, c.column_name, cc.check_clause
        order by n desc) t);
    trig = 'trig_partition_'||parent||'_'||field;
    execute
    'CREATE OR REPLACE FUNCTION '||trig||'() RETURNS TRIGGER AS $BODY2$
      declare
        child text;
      begin
        '||script||'
        ELSE
            EXECUTE ''SELECT create_partition('''''||tbl||'''''::text, '''''||method||'''''::text, '''''||params||'''''::text , ''''''||NEW.'||field||'||''''''::text)'' INTO child;
            EXECUTE ''INSERT INTO ''|| child || '' SELECT $1.*'' USING NEW;
	    END IF;
	    RETURN NULL;
      end;
      $BODY2$
      LANGUAGE ''plpgsql'' VOLATILE;';
    execute 'DROP TRIGGER IF EXISTS t_'||trig||' ON "'||parent||'" CASCADE';
    execute 'CREATE TRIGGER t_'||trig||' BEFORE INSERT ON "'||parent||'" FOR EACH ROW EXECUTE PROCEDURE '||trig||'();';
  return child;
end;
$BODY$ LANGUAGE 'plpgsql';
CREATE OR REPLACE FUNCTION "partition_date" (in params text, in field varchar, in sample timestamp with time zone) RETURNS text[] AS $BODY$
declare
  period varchar:= split_part(params, ',', 1);
  fmt varchar := split_part(params, ',', 2);
  clock timestamp with time zone := to_timestamp(sample);
  delta varchar := '1 '||period;
  suffix varchar;
  check_beg varchar;
  check_end varchar;
  condition varchar;
begin
    -- RAISE EXCEPTION 'period %, fmt %, clock %', period, fmt, clock;
    check_beg = date_trunc(period, clock);
    check_end = date_trunc(period, clock + delta::interval);
    suffix = to_char (clock, fmt);
    condition =
    '(
       ' || field || ' >= ' || quote_literal (check_beg) || ' and
       ' || field || ' < ' || quote_literal (check_end) || '
     )';
    return ARRAY[suffix, condition];
end;
$BODY$ LANGUAGE 'plpgsql' IMMUTABLE;
CREATE OR REPLACE FUNCTION "partition_digits" (in params text, in field varchar, in sample numeric) RETURNS text[] AS $BODY$
declare
  len int := split_part(params, ',', 1)::int;
  pref int := split_part(params, ',', 2)::int;
  norm text := to_char(sample::numeric, 'FM000000000000000000000');
  suffix text := regexp_replace(left(norm, -1*(len-pref)), '0*(?=\d{'||pref::text||'})', '');
  check_beg varchar;
  check_end varchar;
  condition varchar;
begin
    check_beg = (trunc(norm::numeric, -1*(len-pref)))::numeric::text;
    check_end = (check_beg::numeric+10^(len-pref))::numeric::text;
    condition =
    '(
       ' || field || ' >= ' || check_beg || ' and
       ' || field || ' < ' || check_end || '
    )';
    return ARRAY[suffix, condition];
end;
$BODY$ LANGUAGE 'plpgsql' IMMUTABLE;

DROP TABLE IF EXISTS "public"."test1" CASCADE;
CREATE TABLE "public"."test1" (
  "id" serial,
  "cdate" timestamp with time zone,
  "text" text,
  CONSTRAINT "test11_pkey" PRIMARY KEY (id)
) WITH OIDS;
CREATE INDEX test_idx_cdate ON test1 USING btree (cdate);
-- select create_partition('public.test1.cdate', 'date', 'day,YYYY_MM_DD', now()::text);
-- select create_partition('public.test1.cdate', 'date', 'week,YYYY_IW', now()::text);
select create_partition('public.test1.cdate', 'date', 'month,YYYY_MM', now()::text);
-- insert into test1 (cdate, text) SELECT  cdate, md5(random()::text) as text FROM generate_series('2012-01-01'::date, now(), '1 day'::interval) cdate;

DROP TABLE IF EXISTS "public"."test2" CASCADE;
CREATE TABLE "public"."test2" (
  "id" bigserial,
  "text" text,
  CONSTRAINT "test2_pkey" PRIMARY KEY (id)
) WITH OIDS;
select create_partition('public.test2.id', 'digits', '10,2', 1::int);
insert into test2 values(10000000, 'test2');
-- insert into test2 (id, text) SELECT  t.id, md5(random()::text) as text FROM generate_series(0, 100000000000, 1000000000) as t(id) limit 200;