Maximum QPS for Azure PostgreSQL Flexible Server

Question

Maximum QPS for Azure PostgreSQL Flexible Server

Sai 0

Is there a dependency between the maximum queries per second that Azure PostgreSQL Flexible Server can support and the compute SKU of the flexible server?If not what are the factors affecting maximum queries per second that azure postgres flexible server can support?

Prasad Chaganti 80 Reputation points Microsoft External Staff

2025-03-12T00:42:11.47+00:00

Hi Sai,

There is a dependency between the maximum queries per second that Azure PostgreSQL Flexible Server can support and the compute SKU of the flexible server. The compute SKU, which includes the number of vCores and the type of virtual machine (VM) series, directly impacts the performance and capacity of the server. For example, higher vCore counts and more powerful VM series (such as the Memory Optimized series) can handle more queries per second compared to lower vCore counts and less powerful VM series

Other factors affecting the maximum queries per second that Azure PostgreSQL Flexible Server can support include:

1.Memory and Storage: The amount of memory per vCore and the storage size can influence the performance. More memory allows for better caching and faster query processing, while larger storage can handle more data

2.Network Latency: The network configuration and latency between the client and the server can impact the query performance. Lower latency results in faster query execution

3.Database Configuration: The configuration settings of the PostgreSQL database, such as connection pooling, indexing, and query optimization, play a significant role in determining the query performance

4.Workload Characteristics: The nature of the workload, including the complexity of queries, the size of the data being processed, and the concurrency of the queries, can affect the maximum queries per second

I hope this information helps. Please do let us know if you have any further queries.

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Prasad Chaganti 80 Reputation points Microsoft External Staff

2025-03-12T00:42:11.47+00:00

Hi Sai,

There is a dependency between the maximum queries per second that Azure PostgreSQL Flexible Server can support and the compute SKU of the flexible server. The compute SKU, which includes the number of vCores and the type of virtual machine (VM) series, directly impacts the performance and capacity of the server. For example, higher vCore counts and more powerful VM series (such as the Memory Optimized series) can handle more queries per second compared to lower vCore counts and less powerful VM series

Other factors affecting the maximum queries per second that Azure PostgreSQL Flexible Server can support include:

1.Memory and Storage: The amount of memory per vCore and the storage size can influence the performance. More memory allows for better caching and faster query processing, while larger storage can handle more data

2.Network Latency: The network configuration and latency between the client and the server can impact the query performance. Lower latency results in faster query execution

3.Database Configuration: The configuration settings of the PostgreSQL database, such as connection pooling, indexing, and query optimization, play a significant role in determining the query performance

4.Workload Characteristics: The nature of the workload, including the complexity of queries, the size of the data being processed, and the concurrency of the queries, can affect the maximum queries per second

I hope this information helps. Please do let us know if you have any further queries.

Answer 1

Sai 0

Thanks for the response @Prasad Chaganti would like to utilise my azure postgres flexible server with Pgvector extension as vector database which should serve target throughput of 50 queries per second.I am using E8s_v3 Memory optimised Compute SKU with 1TB storage capacity and would like to know whether the configuration handles target throughput of 50 queries per second.Any resources to determine maximum queries per second will be helpful

Prasad Chaganti 80 Reputation points Microsoft External Staff

2025-03-12T22:52:11.6433333+00:00

Hi Sai,

Based on your configuration of an E8s_v3 Memory Optimized Compute SKU with 1TB storage, it is likely that the server can handle a throughput of 50 queries per second, but the actual performance will depend on several factors:

The E8s_v3 SKU has 8 vCores and 64 GB of memory. This should provide sufficient compute and memory to support 50 QPS, especially for read-heavy or moderately complex vector search queries.

Performance with the Pgvector extension will depend on factors such as:

1.Indexing method (HNSW vs IVFFLAT) – HNSW typically provides faster search times but requires more memory.

2.Distance calculation type – Cosine similarity or L2 distance can affect query time.

Ensure that connection pooling is configured properly (e.g using PgBouncer) to handle high concurrency and avoid connection bottlenecks.

Tuning settings like work_mem, shared_buffers, and effective_cache_size can enhance query performance.

The disk I/O limits associated with the SKU can affect query response times, particularly for write-heavy workloads. Ensure the IOPS and throughput are within acceptable ranges for your workload.

For more detailed insights, you can use pg_stat_statements to monitor query performance and adjust configurations as needed.

Refer: https://learn.microsoft.com/en-us/azure/postgresql/flexible-server/

I hope this information helps. Please do let us know if you have any further queries.

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Maximum QPS for Azure PostgreSQL Flexible Server

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