Adaptive Server IQ index types
144
•
VARCHAR
data with more than 255 bytes
HNG
indexes do not allow
FLOAT
,
REAL
, or
DOUBLE
data.
All other data types are supported in all index types.
If you try to create an index on a column that contains
VARCHAR
data greater
than 255 bytes, you get this error message:
An index cannot be created on a varchar column greater
than 255 characters.
Combining index types
If a column is going to be used in more than one type of query, multiple column
index types might be appropriate. The following table shows which index types
make good combinations.
Table 4-4: Mix of valid indexes
Note
The High_Group index in Adaptive Server IQ Version 12.0 differs from
earlier versions. For some columns you may want both High_Group and
High_Non_Group; previously, it did not make sense to have both.
Adaptive Server IQ index types
This section explores in depth the reasons you might use each of the column
index types.
Add Index
Existing Index
HG
HNG
LF
HG
-
1
2
HNG
1
-
1
LF
2
1
-
1 = A reasonable combination
2 = An unlikely combination
Summary of Contents for Adaptive Server IQ 12.4.2
Page 1: ...Administration and Performance Guide Adaptive Server IQ 12 4 2 ...
Page 16: ...xvi ...
Page 20: ...Related documents xx ...
Page 40: ...Compatibility with earlier versions 20 ...
Page 118: ...Troubleshooting startup shutdown and connections 98 ...
Page 248: ...Importing data by replication 228 ...
Page 306: ...Integrity rules in the system tables 286 ...
Page 334: ...Cursors in transactions 314 ...
Page 396: ...Users and permissions in the system tables 376 ...
Page 438: ...Determining your data backup and recovery strategy 418 ...
Page 484: ...Network performance 464 ...
Page 500: ...System utilities to monitor CPU use 480 ...
Page 514: ...Characteristics of Open Client and jConnect connections 494 ...
Page 536: ...Index 516 ...