The SQL database used for ACD contains 113 tables and indices implemented
in GDBM. The following are statistics on the sizes of keys and data
within these tables and indices.
Entries: 962080
Size: 45573853
Avg Size: 48
Key Size: 11045299
Avg Key Size: 12
Max Key Size: 99
Size of key Cummulative
and data Instances Percentage
------------ ---------- -----------
0..8 266 0%
9..12 5485 0%
13..16 73633 8%
17..24 180918 27%
25..32 209823 48%
33..40 148995 64%
41..48 76304 72%
49..56 14346 73%
57..64 15725 75%
65..80 44916 80%
81..96 127815 93%
97..112 34769 96%
113..128 13314 98%
129..144 8098 99%
145..160 3355 99%
161..176 1159 99%
177..192 629 99%
193..208 221 99%
209..224 210 99%
225..240 129 99%
241..256 57 99%
257..288 496 99%
289..320 60 99%
321..352 37 99%
353..384 46 99%
385..416 22 99%
417..448 24 99%
449..480 26 99%
481..512 27 99%
513..1024 471 99%
1025..2048 389 99%
2049..4096 182 99%
4097..8192 74 99%
8193..16384 34 99%
16385..32768 17 99%
32769..65536 5 99%
65537..131073 3 100%
This information is gathered to help design the new built-in
backend for sqlite 2.0. Note in particular that 99% of all
database entries have a combined key and data size of less than
144 bytes. So if a leaf node in the new database is able to
store 144 bytes of combined key and data, only 1% of the leaves
will require overflow pages. Furthermore, note that no key
is larger than 99 bytes, so if the key will never be on an
overflow page.
The average combined size of key+data is 48. Add in 16 bytes of
overhead for a total of 64. That means that a 1K page will
store (on average) about 16 entries.
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