GET /db/mydb/PG_12_201912345/16387/41553.1 HTTP/1.1
Host: www.maytonsfuckendb.org
Range: bytes=127645-4096

c:\ rsync-over-http https://maytons-fucken-server/db c:\PG

granule=4k

hash=crc32

mayton@ryzen-ssd:/bigdata$ 
mayton@ryzen-ssd:/bigdata/pg$ du -h
7.2G	./dht/PG_12_201909212/16387
0	./dht/PG_12_201909212/pgsql_tmp
7.2G	./dht/PG_12_201909212
7.2G	./dht
7.2G	.

dht=> \d+
                                    List of relations
 Schema |          Name           |       Type        | Owner  |    Size    | Description 
--------+-------------------------+-------------------+--------+------------+-------------
 public | X                       | table             | mayton | 8192 bytes | 
 public | assetclass              | table             | mayton | 304 kB     | 
 public | association_value_entry | table             | mayton | 8192 bytes | 
 public | currency                | table             | mayton | 0 bytes    | 
 public | hibernate_sequence      | sequence          | mayton | 8192 bytes | 
 public | instrument              | table             | mayton | 0 bytes    | 
 public | journal                 | table             | mayton | 16 kB      | 
 public | journal_id_seq          | sequence          | mayton | 8192 bytes | 
 public | measurement             | partitioned table | mayton | 0 bytes    | 
 public | measurement_y2006m02    | table             | mayton | 0 bytes    | 
 public | organization            | table             | mayton | 1288 MB    | 
 public | person                  | table             | mayton | 2598 MB    | 
 public | person_p                | partitioned table | mayton | 0 bytes    | 
 public | person_p0               | table             | mayton | 1300 MB    | 
 public | person_p1               | table             | mayton | 1299 MB    | 
 public | saga_entry              | table             | mayton | 8192 bytes | 
 public | test                    | table             | mayton | 0 bytes    | 
 public | test10                  | table             | mayton | 0 bytes    | 
 public | test2                   | table             | mayton | 0 bytes    | 
 public | test3                   | table             | mayton | 0 bytes    | 
 public | test5                   | table             | mayton | 0 bytes    | 
 public | test5_bs_seq            | sequence          | mayton | 8192 bytes | 
 public | test5_se_seq            | sequence          | mayton | 8192 bytes | 
 public | test5_ss_seq            | sequence          | mayton | 8192 bytes | 
 public | token_entry             | table             | mayton | 16 kB      | 
 public | x                       | table             | mayton | 8192 bytes | 
(26 rows)

dht=> select pg_relation_filepath('person');
            pg_relation_filepath             
---------------------------------------------
 pg_tblspc/16386/PG_12_201909212/16387/33252
(1 row)

dht=> select pg_relation_filepath('organization');
            pg_relation_filepath             
---------------------------------------------
 pg_tblspc/16386/PG_12_201909212/16387/33288
(1 row)

total 7500612
-rw-r-x--- 1 postgres postgres 1073741824 Aug 23 23:16 33252*
-rw-r-x--- 1 postgres postgres 1073741824 Aug 23 23:16 33252.1*
-rw-r-x--- 1 postgres postgres 1073741824 Oct  8 00:28 33288*
-rw-r-x--- 1 postgres postgres 1073741824 Oct 30 21:20 41547*
-rw-r-x--- 1 postgres postgres 1073741824 Oct 30 21:20 41553*
-rw-r-x--- 1 postgres postgres  671965184 Aug 23 23:18 33265*
-rw-r-x--- 1 postgres postgres  576299008 Oct  8 00:26 33252.2*
-rw-r-x--- 1 postgres postgres  288563200 Oct 30 22:12 41547.1*
-rw-r-x--- 1 postgres postgres  287744000 Oct 30 22:12 41553.1*
-rw-r-x--- 1 postgres postgres  276938752 Oct  8 00:29 33288.1*
...

-rw-r-x--- 1 postgres postgres 1073741824 Aug 23 23:16 33252*
-rw-r-x--- 1 postgres postgres 1073741824 Aug 23 23:16 33252.1*

dht=> select count(*) from person;
  count
----------
 14383340
(1 row)

dht=> select count(*) from (
dht(>         select person.*, row_number() over () as seqnum from person) t
dht-> where seqnum % 2 = 0;
  count  
---------
 7191670
(1 row)

dht=> show block_size;
 block_size 
------------
 8192
(1 row)

private final Adler32 crc = new Adler32();

mayton@ryzen-ssd:/storage/rsync-http$ tree --charset windows1251 -s
.
|-- [         38]  hash-list
|   `-- [         60]  2020-11-19-20-16-10
|       |-- [    3801088]  33252.1.hashlist
|       `-- [    3801088]  33252.hashlist
`-- [         38]  merkle-tree
    `-- [         52]  2020-11-19-20-16-10
        |-- [    6029307]  33252.1.merkle
        `-- [    6029307]  33252.merkle

dht=> explain delete from person where id in (select id from (
dht(>                                      select person.*, row_number() over () as seqnum from person) t
dht(>                                where seqnum % 2 = 0);
                                                   QUERY PLAN                                                    
-----------------------------------------------------------------------------------------------------------------
 Delete on person  (cost=893393.62..1392046.64 rows=71821 width=489)
   ->  Nested Loop  (cost=893393.62..1392046.64 rows=71821 width=489)
         ->  Unique  (cost=893393.06..893752.17 rows=71821 width=509)
               ->  Sort  (cost=893393.06..893572.61 rows=71821 width=509)
                     Sort Key: ((t.id)::text)
                     ->  Subquery Scan on t  (cost=0.00..871149.94 rows=71821 width=509)
                           Filter: ((t.seqnum % '2'::bigint) = 0)
                           ->  WindowAgg  (cost=0.00..655687.16 rows=14364185 width=467)
                                 ->  Seq Scan on person person_1  (cost=0.00..476134.85 rows=14364185 width=459)
         ->  Index Scan using person_pk on person  (cost=0.56..6.97 rows=1 width=32)
               Index Cond: ((id)::text = (t.id)::text)
 JIT:
   Functions: 11
   Options: Inlining true, Optimization true, Expressions true, Deforming true
(14 rows)

dht=> \d person
                                Table "public.person"
           Column           |          Type          | Collation | Nullable | Default 
----------------------------+------------------------+-----------+----------+---------
 id                         | character varying(255) |           |          | 
 TYPE                       | character varying(23)  |           |          | 
 has_perm_id                | character varying(68)  |           |          | 
 RANK                       | character varying(4)   |           |          | 
 pref_label                 | character varying(86)  |           |          | 
 has_publication_status     | character varying(29)  |           |          | 
 from_institution_name      | character varying(213) |           |          | 
 in_subject                 | character varying(12)  |           |          | 
 with_degree                | character varying(12)  |           |          | 
 TO                         | character varying(22)  |           |          | 
 FROM                       | character varying(22)  |           |          | 
 has_holder                 | character varying(15)  |           |          | 
 is_tenure_in               | character varying(15)  |           |          | 
 has_position_type          | character varying(14)  |           |          | 
 has_reported_title         | character varying(219) |           |          | 
 is_position_in             | character varying(15)  |           |          | 
 has_tenure_in_organization | character varying(15)  |           |          | 
 holds_position             | character varying(68)  |           |          | 
 family_name                | character varying(62)  |           |          | 
 given_name                 | character varying(61)  |           |          | 
 has_gender                 | character varying(8)   |           |          | 
 honorific_prefix           | character varying(27)  |           |          | 
 additional_name            | character varying(37)  |           |          | 
 has_qualification          | character varying(88)  |           |          | 
 honorific_suffix           | character varying(54)  |           |          | 
 preferred_name             | character varying(25)  |           |          | 
 date_of_death              | character varying(12)  |           |          | 
 has_year_of_birth          | character varying(6)   |           |          | 
Indexes:
    "person_pk" UNIQUE, btree (id)

create temporary table person_tmp on commit preserve rows as (select id from (select person.*, row_number() over () as seqnum from 
person) t where seqnum % 2 = 0);

create index person_tmp_idx on person_tmp(id);

analyze verbose person_tmp;

dht=> explain  delete from person where id in (select id from person_tmp);
                                       QUERY PLAN
----------------------------------------------------------------------------------------
 Delete on person  (cost=261621.21..1155451.46 rows=7191387 width=12)
   ->  Hash Semi Join  (cost=261621.21..1155451.46 rows=7191387 width=12)
         Hash Cond: ((person.id)::text = (person_tmp.id)::text)
         ->  Seq Scan on person  (cost=0.00..476326.40 rows=14383340 width=32)
         ->  Hash  (cost=122568.87..122568.87 rows=7191387 width=32)
               ->  Seq Scan on person_tmp  (cost=0.00..122568.87 rows=7191387 width=32)
 JIT:
   Functions: 10
   Options: Inlining true, Optimization true, Expressions true, Deforming true
(9 rows)

dht=> delete from person where id in (select id from person_tmp);

2020-11-19 22:29:29.766 EET [60395] mayton@dht ERROR:  syntax error at or near "for" at character 9
2020-11-19 22:29:29.766 EET [60395] mayton@dht STATEMENT:  explain for delete from person where id in (select id from person_tmp);
2020-11-19 22:35:02.119 EET [1474] LOG:  checkpoints are occurring too frequently (8 seconds apart)
2020-11-19 22:35:02.119 EET [1474] HINT:  Consider increasing the configuration parameter "max_wal_size".
2020-11-19 22:46:45.027 EET [1474] LOG:  checkpoints are occurring too frequently (10 seconds apart)
2020-11-19 22:46:45.027 EET [1474] HINT:  Consider increasing the configuration parameter "max_wal_size".
2020-11-19 23:08:41.339 EET [1474] LOG:  checkpoints are occurring too frequently (2 seconds apart)
2020-11-19 23:08:41.339 EET [1474] HINT:  Consider increasing the configuration parameter "max_wal_size".
2020-11-19 23:16:36.718 EET [1474] LOG:  checkpoints are occurring too frequently (16 seconds apart)
2020-11-19 23:16:36.718 EET [1474] HINT:  Consider increasing the configuration parameter "max_wal_size".

delete from person where substr(md5(id),1,1) in ('0','2','4','6','8','a','c','e');

.....
[INFO ]  : Block # 131067 : hash1 = 'O2vMDnsJlj113qGwYn/qFgK/fRA=', hash2 = 'd82GSvApaNM2frWqLqaRDBecxh0='!
[INFO ]  : Block # 131068 : hash1 = 'r5AO0yB0phKagV9/xVeQ6y0herI=', hash2 = 'qaNmaUjww7HCgDGorL70fWeC428='!
[INFO ]  : Block # 131069 : hash1 = 'V2qnBSO20+LqP8l3W4nswXZI+5Y=', hash2 = 'BPYpJMG+oRvVtOEcAZ2UZcXnBAs='!
[INFO ]  : Block # 131070 : hash1 = 'rJ2+kbVLnp5ZSCIMt4RyfwzY4I8=', hash2 = 'dvoP7c7fnuB9oeRItmljnRsNCbA='!
[INFO ]  : Block # 131071 : hash1 = 'FCX7k52ij977Lj5tVTXFM2MYsQU=', hash2 = 'dNRfxgzPcypbBVUuzlGIovGLlDk='!
[INFO ]  : Equals : 0
[INFO ]  : All    : 131072

GET /db/mydb/PG_12_201912345/16387/readme.lst HTTP/1.1

PUT ....

GET /db/mydb/PG_12_201912345/16387/41553.1.merkle-index.lock

202 Accepted.

HEAD /db/mydb/PG_12_201912345/16387/41553.1.merkle-index.lock

HEAD /db/mydb/PG_12_201912345/16387/41553.1.merkle-index

GET /db/mydb/PG_12_201912345/16387/41553.1.merkle-index
200 OK

GET /db/mydb/PG_12_201912345/16387/41553.1
Range: bytes=0..8192

GET /db/mydb/PG_12_201912345/16387/41553.1
Range: bytes=8192..16384

PUT /db/mydb/PG_12_201912345/16387/41553.1?index=start