Traversal of PostgreSQL arrays

PostgreSQL provides an array type. I'll show you how to use it specifically.
Creates a table with an array type field.

Create table test_array(id serial primary key, str1 int[][][]);
 
 
Insert two test data.
Insert into test_array values (1,array[[[,2],[3,4],[5,6]],[[20,30],[40,50],[70,100]]]);
Insert into test_array values (2,array[[[100,200],[300,400],[500,600]],[[2000,3000],[4000,5000],[7000,10000]]]);

Traversing without sharding,

Create or replace function sp_array2table_simple(
Anyarray
)
Returns table (element int) as
$ytt$
Declare array1 alias for $1;
x int;
Begin
   Drop table if exists tmp_1;
   Create temporary table tmp_1 (id int);
  
   <<label1>> foreach x in array array1
   Loop
     Insert into tmp_1 values (x);
   End loop label1;
  
   Return query select * from tmp_1;
End;
$ytt$ language plpgsql;
 
 
T_girl=#select sp_array2table_simple(str1) as array_list from test_array where id = 2;
 
 
  Array_list
------------
         100
         200
         300
         400
         500
         600
        2000
        3000
        4000
        5000
        7000
       10000
(12 lines of records)
 
 
 
 
Time: 7.780 ms

Traversal with fragmentation:

?

Create or replace function sp_array2table(
Anyarray
)
Returns table (element int) as
$ytt$
Declare array1 alias for $1;
x int[];
Nlen int := 0;
i int := 1;
Begin
   Drop table if exists tmp_1;
   Create temporary table tmp_1 (id int);
  
   <<label1>> foreach x slice 1 in array array1
     Loop
       Nlen := array_length(x,1);
       i := 1;
       <<label2>> while i <= nlen loop
         Insert into tmp_1 values (x[i]);
         i := i + 1;
       End loop label2;
   End loop label1;
  
   Return query select * from tmp_1;
End;
$ytt$ language plpgsql;
 
 
T_girl=#select sp_array2table(str1) as array_list from test_array where id = 2;
 
 
  Array_list
------------
         100
         200
         300
         400
         500
         600
        2000
        3000
        4000
        5000
        7000
       10000
(12 lines of records)
 
 
 
 
Time: 20.139 ms

There is a system of several functions, directly to traverse,

T_girl=#select unnest(str1) as array_list from test_array where id = 2;
 
 
  Array_list
------------
         100
         200
         300
         400
         500
         600
        2000
        3000
        4000
        5000
        7000
       10000
(12 lines of records)
 
 
 
 
Time: 1.002 ms

For example, array_to_string and so on.

T_girl=#select regexp_split_to_table(array_to_string(str1,','),',+') as array_list from test_array where id = 2;
 
 
  Array_list
------------
  100
  200
  300
  400
  500
  600
  2000
  3000
  4000
  5000
  7000
  10000
(12 lines of records)
 
 
 
 
Time: 0.850 ms