Merge pull request #395 from bozhodimitrov/main

Examples for episode 566 & 567

sample_code/ep566/README.md

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+# [ONE TERABYTE of RAM saved with a single line of code (advanced)](https://youtu.be/Hgw_RlCaIds)
+
+Today I show off a small change I made at work with huge impact and explain how it works!
+
+## Setup commands
+
+```bash
+git clone [email protected]:python/cpython
+# git clone https://github.com/python/cpython
+
+cd cpython
+```
+
+## Interactive examples
+
+### Python
+
+```python
+import gc
+gc.freeze()
+```
+
+### Bash
+
+```bash
+git grep 'typedef .* PyObject;'
+git grep 'struct _object'
+nano Include/object.h
+```

sample_code/ep567/README.md

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+# [using memray to debug (and fix) a memory leak in krb5! (advanced)](https://youtu.be/bw5AHdZA7e4)
+
+Today I show how I utilized memray to both find, debug, and ultimately fix a memory leak in krb5 -- sadly this was not the leak I was looking for though!
+
+## Setup commands
+
+```bash
+git clone [email protected]:getsentry/sentry
+# git clone https://github.com/getsentry/sentry
+cd sentry
+```
+
+## Interactive examples
+
+### Bash
+
+Session 1:
+
+```bash
+python -m sentry run worker --queues counters-0 --concurrency 1 --max-tasks-per-child 1000000000
+timeout --signal=SIGINT 10s memray run --quiet -m sentry run worker --queues counters-0 --concurrency 1 --max-tasks-per-child 1000000000
+
+memray flamegraph --help
+memray flamegraph --leaks <memray_bin_filename>
+open <memray_flamegraph_html_filename>
+
+PYTHONMALLOC=malloc timeout --signal=SIGINT 10s memray run --follow-fork --quiet -m sentry run worker --queues counters-0 --concurrency 1 --max-tasks-per-child 1000000000
+memray flamegraph --leaks <memray_bin_filename>
+open <memray_flamegraph_html_filename>
+
+PYTHONMALLOC=malloc timeout --signal=SIGINT 20s memray run --follow-fork --quiet -m sentry run worker --queues counters-0 --concurrency 1 --max-tasks-per-child 1000000000
+memray flamegraph --leaks <memray_bin_filename>
+open <memray_flamegraph_html_filename>
+
+PYTHONMALLOC=malloc memray run -m t
+memray flamegraph --leaks <memray_bin_filename>
+open <memray_flamegraph_html_filename>
+
+PYTHONMALLOC=malloc memray run --native -m t
+memray flamegraph <memray_bin_filename>
+xdg-open <memray_flamegraph_html_filename>
+
+gcc $(PKG_CONFIG_PATH=<broken_version> pkg-config kbr5-gssapi --cflags --libs) t.c
+./a.out
+leaks --atExit -- ./a.out
+
+gcc $(PKG_CONFIG_PATH=<fixed_version> pkg-config kbr5-gssapi --cflags --libs) t.c
+./a.out
+leaks --atExit -- ./a.out
+```
+
+Session 2:
+
+```bash
+sentry exec t.py
+```
+
+Session 3:
+
+```bash
+htop --filter ' worker '
+```

sample_code/ep567/rev01/t.c

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+#include <gssapi.h>
+
+int main(void) {
+    for (int i = 0; i < 10; i += 1) {
+        gss_cred_id_t cred = 0;
+        OM_uint32 minor = 0;
+        OM_uint32 ret = gss_acquire_cred(
+            &minor, GSS_C_NO_NAME, 0, GSS_C_NO_OID_SET,
+            GSS_C_INITIATE, &cred, NULL, NULL
+        );
+        if (ret == GSS_S_COMPLETE) {
+            printf("no error\n");
+            gss_release_cred(&minor, &cred)
+        } else {
+            printf("got error: %d\n", ret)
+        }
+    }
+}

sample_code/ep567/rev01/t.py

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+from sentry.buffer import backend
+from sentry.models.group import Group
+from sentry.models.organization import Organization
+from sentry.models.project import Project
+from sentry.models.release import Release
+from sentry.models.releases.release_project import ReleaseProject
+from sentry.models.team import Team
+
+
+group = Group.objects.create(project=Project(id=1))
+org = Organization.objects.create(slug="test-org")
+team = Team.objects.create(organization=org, slug="test-team")
+project = Project.objects.create(organization=org, slug="test-project")
+project.add_team(team)
+release = Release.objects.create(organization=org, version="abcdefg")
+release_project = ReleaseProject.objects.create(project, release=release)
+
+while True:
+    columns = {"times_seen": 1}
+    filters = {"id": group.id, "project_id": 1}
+    backend.incr(Group, columns, filters)

sample_code/ep567/rev01/t2.py

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+import psycopg2
+
+
+def main():
+    for _ in range(10000):
+        psycopg2.connect("user=postgres host=127.0.0.1 dbname=sentry").close()
+
+
+main()