NDB Ordered Index Status

Alpha release Jan 30, 2004

Up to 32 index attributes of any type, possibly nullable.
Index build i.e. table need not be empty.
Logging NOT done, index rebuilt at system restart.
Single range scan with lower and upper bounds.
Scan with locking: read latest, read for update.
LIMITED number of parallel scans.
Total result set NOT in index key order.
NDB ODBC optimizer to use ordered index for equality but NOT for ranges.
MySQL optimizer to use ordered index for equality and ranges.

As an example, consider following index on integer attributes.

SQL>create index X on T (A, B, C) nologging;

Single range scan means that bounds are set on an initial sequence of index keys, and all but last is an equality.
For example following scans are supported (the last 2 not via NDB ODBC).

SQL>select * from T where A = 1;
SQL>select * from T where A = 1 and B = 10 and C = 20;
SQL>select * from T where A < 10;
SQL>select * from T where A = 1 and 10 < B and B < 20;

Following scans are NOT supported:

SQL>select * from T where B = 1;
SQL>select * from T where A < 10 and B < 20;

Features and dates

[Now = Jan 19]

Feature	Now	Jan 30	Mar 01	Never
Index maintenance	X	-	-	-
Basic scan	X 1)	-	-	-
Scan bounds on nullable attributes	-	X	-	-
Scan with locking	-	X	-	-
NDB ODBC equality bounds	-	X	-	-
MySQL integration	-	X	-	-
Index build	2)	X	-	-
Unlimited number of scans	3)	-	X	-
Total ordering	-	-	X	-
Multiple range scan	-	-	X	-
NDB ODBC range bounds	-	-	-	X
Logging	-	-	-	X

No locking and bounds must be on non-nullable key attributes.
Currently table must be empty when index is created.
Currently limited to 11 simultaneous per fragment.