LDAP Query Calculator
Size LDAP directory load: query rate, cache offload, result bandwidth and per-connection query rate.
Inputs
Total Query Rate
1,000queries/s
Rate Reaching The Directory
400queries/s
Result Bandwidth
144.00Mbit/s
Queries Per Connection
50.0queries/s
Queries Per Day
86,400,000
Step by step
Values used
Application clients = 40 clients; Queries per client per second = 25 queries/s; Entries returned per query = 15 entries; Bytes per returned entry = 1,200 bytes; Client-side cache hit ratio = 60 %; Pooled LDAP connections = 20 connections
LDAP Query
total qps = clients × queries per client per second; directory qps = total × (1 − cache hit ratio).
Result set bandwidth
result bandwidth = qps × entries per query × bytes per entry × 8
Total Query Rate
= 1,000 queries/s
Rate Reaching The Directory
= 400 queries/s
Result Bandwidth
= 144.00 Mbit/s
Queries Per Connection
= 50.0 queries/s
Queries Per Day
= 86,400,000
How it works
Directory load is a product of client count and per-client query rate, reduced by whatever the application caches locally. Result bandwidth matters separately because broad searches returning many entries move far more data than the query count suggests. Unbounded LDAP searches are a classic outage cause: a query returning thousands of entries at hundreds of queries per second saturates both the directory's CPU and the link, even though the query rate looks modest.
Formulas
LDAP Query
total qps = clients × queries per client per second; directory qps = total × (1 − cache hit ratio).
- cache hit ratio
- Fraction answered from the application's own cache
- directory qps
- Searches the directory server actually executes
Result set bandwidth
result bandwidth = qps × entries per query × bytes per entry × 8
- entries per query
- Search result size
- bytes per entry
- Serialised attribute payload per entry
Frequently Asked Questions
How is LDAP Query calculated?
total qps = clients × queries per client per second; directory qps = total × (1 − cache hit ratio). Directory load is a product of client count and per-client query rate, reduced by whatever the application caches locally. Result bandwidth matters separately because broad searches returning many entries move far more data than the query count suggests.
Why does LDAP Query matter?
Unbounded LDAP searches are a classic outage cause: a query returning thousands of entries at hundreds of queries per second saturates both the directory's CPU and the link, even though the query rate looks modest.
What values do I need to enter?
This calculator takes 6 inputs: Application clients, Queries per client per second, Entries returned per query, Bytes per returned entry, Client-side cache hit ratio, Pooled LDAP connections. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
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