在DB2数据库中统计网格索引的方法
今天看了一篇ESRI的官方文章，内容如下：
Technical Article Error: Cannot get Map Layer Spatial Index Statistics for the layer Article ID: 18000 Software: ArcGIS - ArcInfo 8.1, 8.1.2, 8.2, 8.3, 9.0, 9.1, 9.2, 9.3 ArcSDE 8.1, 8.1.2, 8.2, 8.3, 9.0, 9.1, 9.2, 9.3 Platforms: Windows NT 4.0, 2000 AIX 4.3.3.0 Error Message Running sdelayer -o si_stats on a DB2 layer returns the following error: "Error: DBMS does NOT support this function (-1008). Error: Cannot get Map Layer Spatial Index Statistics for the layer." Cause sdelayer -o si_stats is not supported with data stored in DB2. Solution or Workaround There is no solution. ArcSDE does not support this operation as the RDBMS (DB2) does not do so.
大体意思是使用sdelayer –o si_stats命令无法统计DB2数据库中的网格索引。
使用该命令可以统计oracle数据库中的网格索引，可以参考我的另一篇博客：
http://blog.csdn.net/liufeng1980423/archive/2011/03/24/6273915.aspx
我自己用了一下这个命令，的确是不行。后来查了一下DB2的文档，原来DB2数据的Spatial Extender组件提供了一个命令gseidx来统计网格索引，实际上该命令也应该是ESRI和IBM联合开发的。
以下是该命令的用法：
[db2inst1@lstest ~]$ gseidx
Usage: gseidx <connect options> <command>
<connect options>
CONNECT TO database-name [ USER user-id USING password ]
<command>
GET GEOMETRY STATISTICS
{ FOR COLUMN table-schema . table-name ( column-name )
[ USING GRID SIZES ( grid-size-1, grid-size-2, grid-size-3 ) ] |
FOR INDEX index-schema . index-name [ DETAIL ] }
[ ANALYZE number { ROWS | PERCENT } [ ONLY ] ]
[ SHOW [ MINIMUM BOUNDING RECTANGLE ] HISTOGRAM [ WITH n BUCKETS ] ]
[ ADVISE [ GRID SIZES ] ]
主要是两方面的功能：
1. 还没建立索引的情况下，得到各种网格大小的统计值：
[db2inst1@lstest ~]$ gseidx "connect to mydb user sde using esrichina get geometry statistics for column sde.streets(shape) using grid sizes (0.011)" Number of Rows: 2721089 Number of non-empty Geometries: 2721089 Number of empty Geometries: 0 Number of null values: 0 Extent covered by data: Minimum X: -167.540447 Maximum X: -84.901820 Minimum Y: 30.225470 Maximum Y: 71.343960 Grid Level 1 ------------ Grid Size : 0.011 Number of Geometries : 2721088 Number of Index Entries : 3627039 Number of occupied Grid Cells : 432802 Index Entry/Geometry ratio : 1.332937 Geometry/Grid Cell ratio : 6.287143 Maximum number of Geometries per Grid Cell: 521 Minimum number of Geometries per Grid Cell: 1 Index Entries : 1 2 3 4 10 --------------- ------ ------ ------ ------ ------ Absolute : 2051228 554025 14491 92666 8678 Percentage (%): 75.38 20.36 0.53 3.41 0.32 Grid Level 2 ------------ Grid Size : 0 No geometries indexed on this level. Grid Level 3 ------------ Grid Size : 0 No geometries indexed on this level. Grid Level X ------------ Number of Geometries : 1 Number of Index Entries : 1 GSE0000I The operation was completed successfully.
2。 获取现有索引的统计值
[db2inst1@lstest ~]$ gseidx "connect to mydb user sde using esrichina get geometry statistics for index sde.a6_ix1 details show histogram advise"
Number of Rows: 2721089
Number of non-empty Geometries: 2721089
Number of empty Geometries: 0
Number of null values: 0
Extent covered by data:
Minimum X: -167.540447
Maximum X: -84.901820
Minimum Y: 30.225470
Maximum Y: 71.343960
Grid Level 1
------------
Grid Size : 0.011
Number of Geometries : 2721088
Number of Index Entries : 3627039
Number of occupied Grid Cells : 432802
Index Entry/Geometry ratio : 1.332937
Geometry/Grid Cell ratio : 6.287143
Maximum number of Geometries per Grid Cell: 521
Minimum number of Geometries per Grid Cell: 1
Index Entries : 1 2 3 4 10
--------------- ------ ------ ------ ------ ------
Absolute : 2051228 554025 14491 92666 8678
Percentage (%): 75.38 20.36 0.53 3.41 0.32
Grid Level 2
------------
Grid Size : 0
No geometries indexed on this level.
Grid Level 3
------------
Grid Size : 0
No geometries indexed on this level.
Grid Level X
------------
Number of Geometries : 1
Number of Index Entries : 1
Histogram:
----------
MBR Size Geometry Count
-------------------- --------------------
0.000010 112
0.000015 21
0.000020 1186
0.000025 617
0.000030 2206
0.000035 1537
0.000040 2346
0.000045 3854
0.000050 2567
0.000055 6034
0.000060 1618
0.000065 8129
0.000070 3369
0.000075 8007
0.000080 10254
0.000085 1364
0.000090 9200
0.000095 3424
0.000100 8022
0.000150 66341
0.000200 54432
0.000250 64271
0.000300 64382
0.000350 53820
0.000400 66869
0.000450 67226
0.000500 56410
0.000550 62615
0.000600 65197
0.000650 61644
0.000700 53687
0.000750 65454
0.000800 61497
0.000850 49001
0.000900 60382
0.000950 59034
0.001000 46622
0.001500 384115
0.002000 238499
0.002500 165449
0.003000 114574
0.003500 90225
0.004000 78282
0.004500 64538
0.005000 48278
0.005500 40237
0.006000 35074
0.006500 31296
0.007000 29106
0.007500 31278
0.008000 24204
0.008500 22628
0.009000 23168
0.009500 18717
0.010000 15825
0.015000 90616
0.020000 15585
0.025000 3832
0.030000 2201
0.035000 611
Query Window Size: Suggested Grid Sizes: Index Entry Cost:
-------------------- ----------------------------- ----------------------
0.01: 0.0039, 0.0078, 0.016 0.46
0.02: 0.0062, 0.016, 0 1.1
0.05: 0.0098, 0.029, 0 4.7
0.1: 0.016, 0.048, 0 15
0.2: 0.025, 0.075, 0 50
0.5: 0.039, 0, 0 260
1: 0.062, 0, 0 980
2: 0.062, 0, 0 3700
5: 0.16, 0, 0 21000
10: 0.16, 0, 0 85000
20: 0.16, 0, 0 3.3e+05
GSE0000I The operation was completed successfully.
具体更详细信息可以查看
http://publib.boulder.ibm.com/infocenter/db2luw/v9r7/index.jsp