[MCOL-1068] Compression ratio miscalculation when there are uncompressed columns Created: 2017-12-01  Updated: 2017-12-05  Resolved: 2017-12-05

Status: Closed
Project: MariaDB ColumnStore
Component/s: MDB Plugin
Affects Version/s: 1.0.11, 1.1.2
Fix Version/s: 1.0.12, 1.1.3

Type: Bug Priority: Major
Reporter: Andrew Hutchings (Inactive) Assignee: Daniel Lee (Inactive)
Resolution: Fixed Votes: 0
Labels: None

Sprint: 2017-24

 Description   

Where there are uncompressed columns the compression_ratio() procedure miscalculates the result. In addition we should show a real ratio instead of percentages as the percentages appear to confuse users.

 Comments   
Comment by Andrew Hutchings (Inactive) [ 2017-12-01 ]

Pull request for 1.0. Will merge up.

For QA: call compression_ratio(); should now show a result similar to:

+-------------------+
 
| COMPRESSION_RATIO |
 
+-------------------+
 
| 2.2482:1          |
 
+-------------------+

Comment by Daniel Lee (Inactive) [ 2017-12-05 ]

Builds verified: GitHub source

1.0.12-1

[root@localhost ~]# cat mariadb-columnstore-1.0.12-1-centos7.x86_64.bin.tar.txt
/root/columnstore/mariadb-columnstore-server
commit 25e9d054cd3d05683fade1b974e1730316d256ed
Merge: 89b2ea1 7c52a83
Author: David.Hall <david.hall@mariadb.com>
Date: Tue Nov 21 10:49:11 2017 -0600

Merge pull request #79 from mariadb-corporation/MCOL-954-1.0

MCOL-954 Init vtable state

/root/columnstore/mariadb-columnstore-server/mariadb-columnstore-engine
commit b112e826a2793228f5f3c1312fec5291fc1d8bf5
Merge: 7c2640f b657938
Author: David.Hall <david.hall@mariadb.com>
Date: Fri Dec 1 16:17:28 2017 -0600

Merge pull request #338 from mariadb-corporation/MCOL-1068

MCOL-1068 Improve compression_ratio() procedure

1.1.3-1

/root/columnstore/mariadb-columnstore-server
commit 632e265687674fb66bd1d704bc18032b00dd6b17
Merge: 5e9fe52 200f5be
Author: david hill <david.hill@mariadb.com>
Date: Tue Nov 21 15:22:06 2017 -0600

Merge branch 'develop-1.1' of https://github.com/mariadb-corporation/mariadb-columnstore-server into develop-1.1

/root/columnstore/mariadb-columnstore-server/mariadb-columnstore-engine
commit 4d8026618cfb5377c9a200170848092ce5660f10
Author: david hill <david.hill@mariadb.com>
Date: Wed Nov 29 09:36:24 2017 -0600

change how the os_detect is run on remote nodes

output from 1.1.0-1

MariaDB [columnstore_info]> call compression_ratio();
-------------------

COMPRESSION_RATIO

-------------------

89.0574%

-------------------
1 row in set (0.06 sec)

new output:

MariaDB [columnstore_info]> call compression_ratio();
-------------------

COMPRESSION_RATIO

-------------------

0.9343:1

-------------------
1 row in set (0.22 sec)

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