Memory leak via API listtransactions

[CWDT250]

Hello. I use a bitcoind with a large wallet containing about 150K transactions.
Each time the method listtransactions is used the memory consumed by the process grows 100MB. As a result it can take up all possible memory and ends with a kill signal.

System information:
Bitcoin Core 23.0
CentOS 8.4
CPU Cores: 12
RAM: 64GB
SSD: 1TB

[mzumsande]

I tried to reproduce this (Ubuntu 20.04.4 LTS) with a large wallet but could not see a memory leak (also not with valgrind).
What I did see is that repeated calls to listtransactions would lead to a step up in the memory claimed by bitcoind (as seen by top or pmap) that would not be released by the OS (enhanced by the fact that the memory for the large RPC response was reserved twice, fixed in #25237)
But after ~5 calls to listtransactions the memory of bitcoind would not increase any further for me with more listtransactions calls.

[CWDT250]

My application is querying listtransactions "*" 100000000 about once every 1 minute to retrieve a list of all transactions. The request takes about 10 seconds. After each call there is an increase in the consumed memory. Sometimes memory clearing is observed but this is useless and after 2-3 hours bitcoind dies with a kill signal from the OS.

I also additionally checked after 5 or more calls the memory also grows by 100+ MB.