[DERBY-1187] defragment of inplace compress pass for described dataset is not freeing up empty pages.

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 10.1.1.0, 10.1.2.1, 10.1.3.1, 10.2.1.6
• Fix Version/s: 10.1.3.1, 10.2.1.6
• Component/s: Store
• Assignee: Mike Matrigali
• Reporter: Mike Matrigali
• Created: 07/Apr/06 06:45
• Updated: 12/Jul/06 03:24
• Resolved: 08/Apr/06 06:31

Description

For the following script defragment pass is not freeing up the free pages:

drop table t1;
create table t1 (i integer primary key, j integer, c char(200));
insert into t1 values (1, 1, 'a');
insert into t1 (select t1.i + 1, t1.j + 1, t1.c from t1);
insert into t1 (select t1.i + 2, t1.j + 2, t1.c from t1);
insert into t1 (select t1.i + 4, t1.j + 4, t1.c from t1);
insert into t1 (select t1.i + 8, t1.j + 8, t1.c from t1);
insert into t1 (select t1.i + 16, t1.j + 16, t1.c from t1);
insert into t1 (select t1.i + 32, t1.j + 32, t1.c from t1);
insert into t1 (select t1.i + 64, t1.j + 64, t1.c from t1);
insert into t1 (select t1.i + 128, t1.j + 128, t1.c from t1);
insert into t1 (select t1.i + 256, t1.j + 256, t1.c from t1);
insert into t1 (select t1.i + 512, t1.j + 512, t1.c from t1);

delete from t1 where i < 512;

select
cast(conglomeratename as char(12)) as tabname,
isindex,
cast(numallocatedpages as int) as alloc,
numfreepages,
cast(numunfilledpages as int) as unfilled,
pagesize,
estimspacesaving
from new org.apache.derby.diag.SpaceTable('T1') t order by conglomeratename;

CALL SYSCS_UTIL.SYSCS_INPLACE_COMPRESS_TABLE('APP', 'T1', 1, 1, 1);

select
cast(conglomeratename as char(12)) as tabname,
isindex,
cast(numallocatedpages as int) as alloc,
numfreepages,
cast(numunfilledpages as int) as unfilled,
pagesize,
estimspacesaving
from new org.apache.derby.diag.SpaceTable('T1') t order by conglomeratename;

select
cast(conglomeratename as char(12)) as tabname,
isindex,
cast(numallocatedpages as int) as alloc,
numfreepages,
cast(numunfilledpages as int) as unfilled,
pagesize,
estimspacesaving
from new org.apache.derby.diag.SpaceTable('T1') t order by conglomeratename;

Here is example output from a run on the trunk:
ij> drop table t1;
0 rows inserted/updated/deleted
ij> create table t1 (i integer primary key, j integer, c char(200));
0 rows inserted/updated/deleted
ij> insert into t1 values (1, 1, 'a');
1 row inserted/updated/deleted
ij> insert into t1 (select t1.i + 1, t1.j + 1, t1.c from t1);
1 row inserted/updated/deleted
ij> insert into t1 (select t1.i + 2, t1.j + 2, t1.c from t1);
2 rows inserted/updated/deleted
ij> insert into t1 (select t1.i + 4, t1.j + 4, t1.c from t1);
4 rows inserted/updated/deleted
ij> insert into t1 (select t1.i + 8, t1.j + 8, t1.c from t1);
8 rows inserted/updated/deleted
ij> insert into t1 (select t1.i + 16, t1.j + 16, t1.c from t1);
16 rows inserted/updated/deleted
ij> insert into t1 (select t1.i + 32, t1.j + 32, t1.c from t1);
32 rows inserted/updated/deleted
ij> insert into t1 (select t1.i + 64, t1.j + 64, t1.c from t1);
64 rows inserted/updated/deleted
ij> insert into t1 (select t1.i + 128, t1.j + 128, t1.c from t1);
128 rows inserted/updated/deleted
ij> insert into t1 (select t1.i + 256, t1.j + 256, t1.c from t1);
256 rows inserted/updated/deleted
ij> insert into t1 (select t1.i + 512, t1.j + 512, t1.c from t1);
512 rows inserted/updated/deleted
ij> delete from t1 where i < 512;
511 rows inserted/updated/deleted
ij> select
cast(conglomeratename as char(12)) as tabname,
isindex,
cast(numallocatedpages as int) as alloc,
numfreepages,
cast(numunfilledpages as int) as unfilled,
pagesize,
estimspacesaving
from new org.apache.derby.diag.SpaceTable('T1') t order by conglomeratename;
TABNAME |ISIND&|ALLOC |NUMFREEPAGES |UNFILLED |PAGESIZE |EST
IMSPACESAVING
--------------------------------------------------------------------------------
-----------------
SQL060406034|1 |7 |0 |0 |4096 |0

T1 |0 |60 |9 |0 |4096 |368
64

2 rows selected
ij> CALL SYSCS_UTIL.SYSCS_INPLACE_COMPRESS_TABLE('APP', 'T1', 1, 1, 1);
0 rows inserted/updated/deleted
ij> select
cast(conglomeratename as char(12)) as tabname,
isindex,
cast(numallocatedpages as int) as alloc,
numfreepages,
cast(numunfilledpages as int) as unfilled,
pagesize,
estimspacesaving
from new org.apache.derby.diag.SpaceTable('T1') t order by conglomeratename;
TABNAME |ISIND&|ALLOC |NUMFREEPAGES |UNFILLED |PAGESIZE |EST
IMSPACESAVING
--------------------------------------------------------------------------------
-----------------
SQL060406034|1 |7 |0 |1 |4096 |0

T1 |0 |69 |0 |0 |4096 |0

2 rows selected
ij>