HeapSize

[fabltd]

When using this libiary I am seeing a sizable reduction in heapsize.

Before MQTT Connection:
free heap size = 99900           min_free_heap_size = 83408 

Connected to MQTT.

 free heap size = 59188           min_free_heap_size = 45432 

Any suggestions on how to reduce this.

I am also trying to use the HTTPS OTA but this is crashes due to insufficant free heap.

Help...

Thanks

[bertmelis]

Did you read the issue template?
Hardware? TLS?

[fabltd]

My appogies

ESP32-WROOM-32D yes using TLS = espMqttClientSecure mqttClient;

[bertmelis]

I guess it's the TLS client. The underlying "client context" is created in heap memory. Not much I can do here.

[fabltd]

There are some ways to reduce the TLS client memory any idea where I would set this?

[bertmelis]

I don't know, never explored this area.

[Pablo2048]

@fabltd if you are on ESP32 there is no easy way AFAIK, because the MBEDTLS_SSL_MAX_CONTENT_LEN constant is compile time constant used in all SSL connections and came from CONFIG_MBEDTLS_SSL_MAX_CONTENT_LEN from sdkconfig.h (that is why i love BearSSL much more over mbedTLS). So the only chance I see is to reconfigure the SDK and rebuild all libraries.

[proddy]

BearSSL on an ESP32 has a much lighter footprint than MbedTLS (45kB vs 150kB). Tasmota has a trimmed down arduino/espressif32 core you can use that uses BearSSL. Try replacing the platform in your PIO ini with

platform = https://github.com/tasmota/platform-espressif32.git

or a specific version like

platform = https://github.com/tasmota/platform-espressif32/releases/download/2023.10.03/platform-espressif32-2023.10.03.zip

[dzungpv]

@fabltd If you convert your project to use ESP IDF (It is still Arduino) you can re-config MbedTLS to meet you need, instead using default build, recently I added support this lib to use ESP IDF, you can see variables to config here: https://docs.espressif.com/projects/esp-idf/en/v4.4.6/esp32/api-reference/kconfig.html#component-config-mbedtls. Update: other solution is use ESP32 with PSRAM.