Estimating SQLFire Overhead

SQLFire requires different amounts of overhead per table and index entry depending on whether you persist table data or configure tables for overflow to disk. Add these overhead figures to the estimated size of each table or index entry to provide a rough estimate for your data memory requirements. If you already have representative data, use the SQLFire Java agent to query the SYS.MEMORYANALYTICS table to obtain a more accurate picture of the memory required to store your data.

Note: All overhead values are approximate. Be sure to validate your estimates in a test environment with representative data.
Table 1. Approximate Overhead for SQLFire Table Entries
Table is persisted? Overflow is configured? Approximate overhead
No No 64 bytes
Yes No 120 bytes
Yes Yes 152 bytes
Table 2. Approximate Overhead for SQLFire Index Entries
Type of index entry Approximate overhead
New index entry 80 bytes
First non-unique index entry 24 bytes
Subsequent non-unique index entry 8 bytes to 24 bytes*

*If there are more than 100 entries for a single index entry, the overhead per entry increases from 8 bytes to approximately 24 bytes.