recreate table t(id int primary key, s01 varchar(36), s02 varchar(36), s03 varchar(36) );
commit;
create index t_s01 on t(s01);
create index t_s02 on t(s02);
create index t_s03 on t(s03);
commit;
set term ^;
execute block as
begin
  begin
    execute statement 'create sequence g';
    when any do begin end
  end
end^
set term ;^
commit;
alter sequence g restart with 0;
commit;

-- 1'000'000 ==> 352 Mb
-- 5'000'000 ==> 1700Mb, ~7 min
set stat on;
set term ^;
execute block as
  declare n int = 5000000;
begin
  while (n>0) do
    insert into t(id, s01, s02, s03)
    values( :n +iif( mod(:n,1000)=0, 0*gen_id(g,1000), 0),
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid())
          ) returning :n-1 into n;
end^
set term ;^

set echo on;

commit;
select count(*) from t;
delete from t;
commit;
set echo off;
show version;
show database;
set echo on;
exit;

$ /opt/fb30trnk/bin/isql -q
SQL> create database 'tmpram.fdb';
SQL> quit;

$ /opt/fb30trnk/bin/gfix -w async /dev/shm/tmpram.fdb

$ /opt/fb30trnk/bin/gstat -h tmpram.fdb |grep -i attributes
        Attributes

$ /opt/fb30trnk/bin/isql localhost/3333:/dev/shm/tmpram.fdb
Database:  localhost/3333:/dev/shm/tmpram.fdb

SQL> in /var/db/fb30/instest.sql;
Current memory = 12594992
Delta memory = 206248
Max memory = 17706016
Elapsed time= 381.750 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 20827420
Writes = 15445615
Fetches = 111122956

commit;
Current memory = 12520344
Delta memory = -74648
Max memory = 17706016
Elapsed time= 0.004 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 1
Writes = 1106
Fetches = 2
select count(*) from t;

                COUNT
=====================
              5000000

Current memory = 12557232
Delta memory = 25800
Max memory = 17706016
Elapsed time= 3.134 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 200440
Writes = 0
Fetches = 10400445

delete from t;
Current memory = 12659296
Delta memory = 102064
Max memory = 17770280
Elapsed time= 11.779 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 200448
Writes = 198001
Fetches = 25400488

commit;
Current memory = 12633744
Delta memory = -25552
Max memory = 17770280
Elapsed time= 0.006 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 1
Writes = 2001
Fetches = 2

set echo off;
ISQL Version: LI-T3.0.0.30876 Firebird 3.0 Alpha 2
Server version:
Firebird/Linux/AMD/Intel/x64 (access method), version "LI-T3.0.0.30876 Firebird 3.0 Alpha 2"
Firebird/Linux/AMD/Intel/x64 (remote server), version "LI-T3.0.0.30876 Firebird 3.0 Alpha 2/tcp (oel64)/P13"
Firebird/Linux/AMD/Intel/x64 (remote interface), version "LI-T3.0.0.30876 Firebird 3.0 Alpha 2/tcp (oel64)/P13"
on disk structure version 12.0
Database: localhost/3333:/dev/shm/tmpram.fdb
        Owner: SYSDBA
PAGE_SIZE 4096
Number of DB pages allocated = 435904
Sweep interval = 20000
Forced Writes are OFF
Transaction - oldest = 22
Transaction - oldest active = 23
Transaction - oldest snapshot = 23
Transaction - Next = 24
ODS = 12.0
Default Character set: NONE
exit;

$ /opt/fb30trnk/bin/isql -q
SQL> create database '/tmp/tmphdd.fdb';
SQL> quit;

$ /opt/fb30trnk/bin/gfix -w async /tmp/tmphdd.fdb


$ /opt/fb30trnk/bin/gstat -h /tmp/tmphdd.fdb | grep -i attributes
        Attributes


$ /opt/fb30trnk/bin/isql localhost/3333:/tmp/tmphdd.fdb -i /var/db/fb30/instest.sql
Current memory = 12594984
Delta memory = 206248
Max memory = 17706008
Elapsed time= 443.738 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 20826670
Writes = 15444747
Fetches = 111069310

commit;
Current memory = 12520336
Delta memory = -74648
Max memory = 17706008
Elapsed time= 0.025 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 1
Writes = 1129
Fetches = 2

select count(*) from t;

                COUNT
=====================
              5000000

Current memory = 12557224
Delta memory = 25800
Max memory = 17706008
Elapsed time= 3.191 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 200440
Writes = 0
Fetches = 10400445

delete from t;
Current memory = 12659288
Delta memory = 102064
Max memory = 17770272
Elapsed time= 11.895 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 200448
Writes = 198056
Fetches = 25400488

commit;
Current memory = 12633736
Delta memory = -25552
Max memory = 17770272
Elapsed time= 0.007 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 1
Writes = 1946
Fetches = 2

set echo off;
ISQL Version: LI-T3.0.0.30876 Firebird 3.0 Alpha 2
Server version:
Firebird/Linux/AMD/Intel/x64 (access method), version "LI-T3.0.0.30876 Firebird 3.0 Alpha 2"
Firebird/Linux/AMD/Intel/x64 (remote server), version "LI-T3.0.0.30876 Firebird 3.0 Alpha 2/tcp (oel64)/P13"
Firebird/Linux/AMD/Intel/x64 (remote interface), version "LI-T3.0.0.30876 Firebird 3.0 Alpha 2/tcp (oel64)/P13"
on disk structure version 12.0
Database: localhost/3333:/tmp/tmphdd.fdb
        Owner: SYSDBA
PAGE_SIZE 4096
Number of DB pages allocated = 435776
Sweep interval = 20000
Forced Writes are OFF
Transaction - oldest = 22
Transaction - oldest active = 23
Transaction - oldest snapshot = 23
Transaction - Next = 24
ODS = 12.0
Default Character set: NONE
exit;

set autoddl off;
commit;
recreate global temporary table gtt(id int, s01 varchar(36), s02 varchar(36), s03 varchar(36) )
on commit preserve rows;
commit;

set stat on;
set echo on;
set term ^;
execute block as
  declare n int = 5000000;
  declare i int = 0;
begin
  while (i<n) do
    insert into gtt(id, s01, s02, s03)
    values( :i,
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid())
          ) returning :i+1 into i;
end^
set term ;^
set stat off;
set echo on;
create unique index t_id on gtt(id);
create index t_s01 on gtt(s01);
create index t_s02 on gtt(s02);
create index t_s03 on gtt(s03);
set stat on;
commit;
exit;

set term ^;
execute block as
  declare n int = 5000000;
  declare i int = 0;
begin
  while (i<n) do
    insert into gtt(id, s01, s02, s03)
    values( :i,
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid())
          ) returning :i+1 into i;
end^
Current memory = 20987952
Delta memory = 103768
Max memory = 23776040
 Elapsed time= 133.044 sec 
Cpu = 0.000 sec
Buffers = 2048
Reads = 5
Writes = 98136
Fetches = 15801650
set term ;^
set stat off;
set echo on;

create unique index t_id on gtt(id);
create index t_s01 on gtt(s01);
create index t_s02 on gtt(s02);
create index t_s03 on gtt(s03);
set stat on;
commit;
Current memory = 21203848
Delta memory = 168672
Max memory = 357819008
 Elapsed time= 32.622 sec 
Cpu = 0.000 sec
Buffers = 2048
Reads = 400336
Writes = 75565
Fetches = 40948184
exit;

set autoddl off;
commit;
recreate global temporary table gtt(id int, s01 varchar(36), s02 varchar(36), s03 varchar(36) )
on commit preserve rows;
commit;
create unique index t_id on gtt(id);
create index t_s01 on gtt(s01);
create index t_s02 on gtt(s02);
create index t_s03 on gtt(s03);
commit;

set stat on;
set echo on;
set term ^;
execute block as
  declare n int = 5000000;
  declare i int = 0;
begin
  while (i<n) do
    insert into gtt(id, s01, s02, s03)
    values( :i,
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid())
          ) returning :i+1 into i;
end^
set term ;^
commit;
exit;

set term ^;
execute block as
  declare n int = 5000000;
  declare i int = 0;
begin
  while (i<n) do
    insert into gtt(id, s01, s02, s03)
    values( :i,
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid()),
            uuid_to_char(gen_uuid())
          ) returning :i+1 into i;
end^
Current memory = 21257024
Delta memory = 90056
Max memory = 24045376
 Elapsed time= 471.882 sec 
Cpu = 0.000 sec
Buffers = 2048
Reads = 14370102
Writes = 13999718
Fetches = 99245515
set term ;^
commit;
Current memory = 21201064
Delta memory = -55960
Max memory = 24045376
Elapsed time= 0.007 sec
Cpu = 0.000 sec
Buffers = 2048
Reads = 1
Writes = 1385
Fetches = 1
exit;