# slow inventory build **URL:** \ **Category:** Ansible Project\ **Created:** [December 28, 2022, 4:42pm UTC](https://forum.ansible.com/t/slow-inventory-build/37505 "2022-12-28T16:42:39Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![mdidomenico](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mdidomenico](https://forum.ansible.com/u/mdidomenico)\ **Post date:** [December 28, 2022, 4:42pm UTC](https://forum.ansible.com/t/slow-inventory-build/37505/1 "2022-12-28T16:42:39Z")
i have a flat list of hosts, no groups, no variables, total is over 15k. when i run $ head inv-expanded.yml all:   hosts:     admin:     admin1:     admin2:     admin3:     admin4:     admin5:     admin6: ...snipped... $ time ansible-inventory -i inv-expanded.yml --list \> a real 0m28.334s user 0m23.725s sys 0m4.452s $ ansible-inventory --version ansible-inventory 2.9.27   config file = /etc/ansible/ansible.cfg   configured module search path = ['/usr/share/ansible/plugins/modules']   ansible python module location = /usr/lib/python3.6/site-packages/ansible   executable location = /usr/bin/ansible-inventory   python version = 3.6.8 (default, Oct 20 2022, 09:31:56) [GCC 8.5.0 20210514 (Red Hat 8.5.0-15)] $ head -n20 /proc/cpuinfo processor : 0 vendor\_id : AuthenticAMD cpu family : 23 model : 49 model name : AMD EPYC 7302P 16-Core Processor stepping : 0 microcode : 0x8301055 cpu MHz : 3000.000 cache size : 512 KB when i include the groups and variables this slows down even more. this ticket [https://github.com/ansible/ansible/issues/30534](https://github.com/ansible/ansible/issues/30534) seems to claim that there used to be an issue in the v2.3/v2.4 era, but it was fixed and i should be seeing ~6s or less is there a way to speed this up without splitting the inventory file into multiple smaller files? ---
**Author:** ![system](https://us1.discourse-cdn.com/ansible/original/1X/1882d9a01da5d8996a862359b0913cc568a39b84.svg) [@system](https://forum.ansible.com/u/system)\ **Post date:** [December 31, 2022, 11:48pm UTC](https://forum.ansible.com/t/slow-inventory-build/37505/2 "2022-12-31T23:48:01Z")
Do you have libyaml installed? it is the C version of the YAML tokenizer, if not the processing will be done in python, which is much slower. The difference is not noticeable with small files, but it really becomes visible with large ones. ---
**Author:** ![mdidomenico](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mdidomenico](https://forum.ansible.com/u/mdidomenico)\ **Post date:** [January 3, 2023, 3:35pm UTC](https://forum.ansible.com/t/slow-inventory-build/37505/3 "2023-01-03T15:35:59Z")
it is installed. is there a way for me to confirm that ansible is actually using it? $ rpm -qa | grep -i yaml perl-CPAN-Meta-YAML-0.018-397.el8.noarch python3-pyyaml-3.12-12.el8.x86\_64 libyaml-0.1.7-5.el8.x86\_64 ---
**Author:** ![system](https://us1.discourse-cdn.com/ansible/original/1X/1882d9a01da5d8996a862359b0913cc568a39b84.svg) [@system](https://forum.ansible.com/u/system)\ **Post date:** [January 5, 2023, 4:52pm UTC](https://forum.ansible.com/t/slow-inventory-build/37505/4 "2023-01-05T16:52:13Z")
It could be related to this [https://github.com/ansible/ansible/issues/79652](https://github.com/ansible/ansible/issues/79652) (see linked PR for fix), but you really don't provide enough information. ---
**Author:** ![Will\_McDonald](https://avatars.discourse-cdn.com/v4/letter/w/f475e1/32.png) [@Will\_McDonald](https://forum.ansible.com/u/Will_McDonald)\ **Post date:** [January 5, 2023, 5:14pm UTC](https://forum.ansible.com/t/slow-inventory-build/37505/5 "2023-01-05T17:14:55Z")
You can strace the ansible-inventory execution to check what libraries and syscalls are used: $ strace ansible-inventory -i inventory/hosts --list 2\>&1 | grep libya openat(AT\_FDCWD, “/lib64/libyaml-0.so.2”, O\_RDONLY|O\_CLOEXEC) = 3 $ rpm -qf /lib64/libyaml-0.so.2 libyaml-0.2.5-8.fc37.x86\_64 ---
**Author:** ![mdidomenico](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mdidomenico](https://forum.ansible.com/u/mdidomenico)\ **Post date:** [January 5, 2023, 6:48pm UTC](https://forum.ansible.com/t/slow-inventory-build/37505/6 "2023-01-05T18:48:49Z")
thanks i did see that yesterday when i opened my ticket. [https://github.com/ansible/ansible/issues/79664](https://github.com/ansible/ansible/issues/79664) if there's more info i can provide please let me know ---
**Author:** ![mdidomenico](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mdidomenico](https://forum.ansible.com/u/mdidomenico)\ **Post date:** [January 5, 2023, 6:55pm UTC](https://forum.ansible.com/t/slow-inventory-build/37505/7 "2023-01-05T18:55:12Z")
ah, yes your right for some reason that didn't jump into my head. i am in fact using libyaml inventory-testing]$ strace ansible-inventory -i ./inv.py --list 1\>a 2\>&1 [inventory-testing]$ grep libyaml a openat(AT\_FDCWD, "/lib64/libyaml-0.so.2", O\_RDONLY|O\_CLOEXEC) = 3 i also found this interesting, seems excessive [[inventory-testing]$ grep open a | sort | uniq -c | grep -v "^ [1-9]"   18591 openat(AT\_FDCWD, "/home/user/.ansible/plugins/connection", O\_RDONLY|O\_NONBLOCK|O\_CLOEXEC|O\_DIRECTORY) = -1 ENOENT (No such file or directory) 111536 openat(AT\_FDCWD, "/home/user/.ansible/plugins/vars", O\_RDONLY|O\_NONBLOCK|O\_CLOEXEC|O\_DIRECTORY) = -1 ENOENT (No such file or directory)   18590 openat(AT\_FDCWD, "/usr/lib/python3.6/site-packages/ansible/plugins/connection", O\_RDONLY|O\_NONBLOCK|O\_CLOEXEC|O\_DIRECTORY) = 3   18590 openat(AT\_FDCWD, "/usr/lib/python3.6/site-packages/ansible/plugins/connection/\_\_pycache\_\_", O\_RDONLY|O\_NONBLOCK|O\_CLOEXEC|O\_DIRECTORY) = 3 111535 openat(AT\_FDCWD, "/usr/lib/python3.6/site-packages/ansible/plugins/vars", O\_RDONLY|O\_NONBLOCK|O\_CLOEXEC|O\_DIRECTORY) = 3 111535 openat(AT\_FDCWD, "/usr/lib/python3.6/site-packages/ansible/plugins/vars/\_\_pycache\_\_", O\_RDONLY|O\_NONBLOCK|O\_CLOEXEC|O\_DIRECTORY) = 3   18591 openat(AT\_FDCWD, "/usr/share/ansible/plugins/connection", O\_RDONLY|O\_NONBLOCK|O\_CLOEXEC|O\_DIRECTORY) = 3 111536 openat(AT\_FDCWD, "/usr/share/ansible/plugins/vars", O\_RDONLY|O\_NONBLOCK|O\_CLOEXEC|O\_DIRECTORY) = 3      22 stat("/usr/lib64/python3.6/site-packages/cryptography/hazmat/backends/openssl", {st\_mode=S\_IFDIR|0755, st\_size=4096, ...}) = 0