solidDB® contains a protection against duplicate indexes. Occasionally, the recreation of an index (DROP/CREATE) can fail if other indexes were created whereby the original index became a duplicate index.
For example, you could create a table containing five columns, named A, B, C, D, E, and create the following indexes on the table:
▪B
▪AB
▪BCE
▪ABC
Index B is used for searching or filtering column B. Index BCE starts with column B. Therefore, queries that use an index for locating column B can use index BCE. The same is the case with indexes AB and ABC. Thus, indexes B and AB are duplicate indexes.
Duplicate indexes have, for example, the following adverse effects:
▪The required storage space increases.
▪The update performance decreases.
▪Backup time increases.
If you attempt to create duplicate indexes, index creation fails and solidDB® issues the following error:
SOLID Table Error 13199: Duplicate index definition
For more information, see “Error codes” in solidDB® Administrator Guide.