Raising max_connections is not always better. Blindly raising it up will lead to resource contention and performance degradation. max_connections is a parameter that limits the number of simultaneous connections in the database. Each connection occupies memory and CPU. If it is set too high, it may exhaust resources. If it is too low, it may limit concurrency. Reasons that cannot be regulating it all include: 1. Each connection consumes resources; 2. Too many connections cause competition and waiting; 3. Restricted by system file descriptors and thread count; 4. It is difficult to run stably without a connection pool. Reasonable setup methods include: 1. Evaluate connection requirements based on load; 2. Use connection pools to reduce direct connections; 3. Monitor system resource bottlenecks; 4. Distinguish between active and idle connections. Suitable cases for raising the height are: 1. The connection pool is not used and the concurrent high is high; 2. The resources are sufficient and there is no competition; 3. Frequent connection errors occur. Priority should be given to optimizing connection management before adjustment rather than directly adding parameters.

Improving the max_connections parameter is not always a better choice. While it allows the database to process more connections at the same time, blindly increasing this value can cause problems such as resource contention, performance degradation and even system crashes.

What are max_connections?

This is a configuration parameter in a database (such as PostgreSQL, MySQL) to limit the maximum number of connections that can be established simultaneously. Each connection will occupy a certain amount of memory and CPU resources, so setting too high may cause resource exhaustion, and too low will limit concurrent access capabilities.

Why can't we just focus on max_connections?

Many people think that the more connections the better, but in fact:

• Each connection consumes resources : such as memory, thread scheduling, etc. A connection in PostgreSQL may use several MB of memory by default, and thousands of connections add up to tens of GB.
• Connection competition will lead to performance degradation : when the number of connections exceeds the processing capacity of the database, waiting, lock competition, and querying will slow down.
• The operating system also has upper limits : system file descriptors, thread counts, etc., and may not necessarily support the max_connections you set.

For example, if your application creates a new connection every time it requests, without using a connection pool, it will be difficult to truly run stably even if tens of thousands of connections are set up.

How to set max_connections reasonably?

Here are a few practical suggestions:

• ?Asessment based on actual load : Observe the number of active connections during peak periods and keep a certain margin.
• ?Used with connection pooling : Connection pooling middleware like PgBouncer or MySQL can greatly reduce the number of direct connections to the database.
• ? Monitor system resources : whether the memory, CPU, and file handles are close to the bottleneck.
• ?Distinguish between active and idle connections : Some connections are hung and do not mean that so much concurrency is really needed.

It is generally recommended to start with the default value, adjust it step by step, and verify the effect in stress tests.

Which situations are suitable for max_connections?

It's not that it cannot be raised. The following scenarios are indeed necessary:

• Your application does not use a connection pool and has many concurrent users.
• The database server has sufficient resources and other services will not compete with it for resources.
• It is clear that "too many connections" errors occur frequently.

But before making adjustments, it is best to see if it can be solved by optimizing connection management instead of directly adding parameters.

Basically that's it. The higher the adjustment parameters, the better. The key is to match actual needs and resource capabilities.

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