PostgreSQL DROP TABLE before checkpointing

postgresql.log.1

LOG:  statement: create table dt (data text);
LOG:  statement: insert into dt (data) values ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa');
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  checkpoint starting: time
LOG:  checkpoint complete: wrote 844 buffers (5.2%); 0 transaction log file(s) added, 0 removed, 1 recycled; write=14.841 s, sync=0.069 s, total=14.917 s; sync files=19, longest=0.065 s, average=0.003 s

postgresql.log.2

LOG:  statement: drop table dt;
LOG:  checkpoint starting: time
LOG:  checkpoint complete: wrote 8 buffers (0.0%); 0 transaction log file(s) added, 0 removed, 0 recycled; write=0.706 s, sync=0.002 s, total=0.710 s; sync files=7, longest=0.001 s, average=0.000 s
LOG:  statement: create table dt (data text);
LOG:  statement: insert into dt (data) values ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa');
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: drop table dt;
LOG:  checkpoint starting: time
LOG:  checkpoint complete: wrote 21 buffers (0.1%); 0 transaction log file(s) added, 0 removed, 0 recycled; write=1.915 s, sync=0.002 s, total=1.920 s; sync files=15, longest=0.001 s, average=0.000 s

postgresql.log.3

LOG:  statement: drop table dt;
LOG:  statement: create table dt (data text);
LOG:  checkpoint starting: time
LOG:  checkpoint complete: wrote 21 buffers (0.1%); 0 transaction log file(s) added, 0 removed, 0 recycled; write=2.016 s, sync=0.003 s, total=2.021 s; sync files=15, longest=0.001 s, average=0.000 s
LOG:  statement: insert into dt (data) values ('aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa');
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: insert into dt select * from dt;
LOG:  statement: delete from dt where data is not null;
LOG:  checkpoint starting: time
LOG:  checkpoint complete: wrote 412 buffers (2.5%); 0 transaction log file(s) added, 0 removed, 0 recycled; write=14.922 s, sync=0.009 s, total=14.932 s; sync files=4, longest=0.008 s, average=0.002 s