html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,issue,performed_via_github_app
https://github.com/simonw/datasette/issues/1836#issuecomment-1272357976,https://api.github.com/repos/simonw/datasette/issues/1836,1272357976,IC_kwDOBm6k_c5L1qRY,536941,2022-10-08T16:56:51Z,2022-10-08T16:56:51Z,CONTRIBUTOR,"when you are running from docker, you **always** will want to run as `mode=ro` because the same thing that is causing duplication in the inspect layer will cause duplication in the final container read/write layer when `datasette serve` runs.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1271103097,https://api.github.com/repos/simonw/datasette/issues/1836,1271103097,IC_kwDOBm6k_c5Lw355,536941,2022-10-07T04:43:41Z,2022-10-07T04:43:41Z,CONTRIBUTOR,"@simonw, should i open up a new issue for investigating the differences between ""immutable=1"" and ""mode=ro"" and possibly switching to ""mode=ro"". Or would you like to keep that conversation in this issue?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1271100651,https://api.github.com/repos/simonw/datasette/issues/1836,1271100651,IC_kwDOBm6k_c5Lw3Tr,536941,2022-10-07T04:38:14Z,2022-10-07T04:38:14Z,CONTRIBUTOR,"> yes, and i also think that this is causing the apparent memory problems in #1480. when the container starts up, it will make some operation on the database in `immutable` mode which apparently makes some small change to the db file. if that's so, then the db files will be copied to the read/write layer which counts against cloudrun's memory allocation!
>
> running a test of that now.
this completely addressed #1480 ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1271020193,https://api.github.com/repos/simonw/datasette/issues/1836,1271020193,IC_kwDOBm6k_c5Lwjqh,536941,2022-10-07T02:15:05Z,2022-10-07T02:21:08Z,CONTRIBUTOR,"when i hack the connect method to open non mutable files with ""mode=ro"" and not ""immutable=1"" https://github.com/simonw/datasette/blob/eff112498ecc499323c26612d707908831446d25/datasette/database.py#L79
then:
```bash
870 B RUN /bin/sh -c datasette inspect nlrb.db --inspect-file inspect-data.json
```
the `datasette inspect` layer is only the size of the json file!","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1271008997,https://api.github.com/repos/simonw/datasette/issues/1836,1271008997,IC_kwDOBm6k_c5Lwg7l,536941,2022-10-07T02:00:37Z,2022-10-07T02:00:49Z,CONTRIBUTOR,"yes, and i also think that this is causing the apparent memory problems in #1480. when the container starts up, it will make some operation on the database in `immutable` mode which apparently makes some small change to the db file. if that's so, then the db files will be copied to the read/write layer which counts against cloudrun's memory allocation!
running a test of that now. ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1271003212,https://api.github.com/repos/simonw/datasette/issues/1836,1271003212,IC_kwDOBm6k_c5LwfhM,536941,2022-10-07T01:52:04Z,2022-10-07T01:52:04Z,CONTRIBUTOR,"and if we try immutable mode, which is how things are opened by `datasette inspect` we duplicate the files!!!
```python
# test_sql_immutable.py
import sqlite3
import sys
db_name = sys.argv[1]
conn = sqlite3.connect(f'file:/app/{db_name}?immutable=1', uri=True)
cur = conn.cursor()
cur.execute('select count(*) from filing')
print(cur.fetchone())
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1270992795,https://api.github.com/repos/simonw/datasette/issues/1836,1270992795,IC_kwDOBm6k_c5Lwc-b,536941,2022-10-07T01:29:15Z,2022-10-07T01:50:14Z,CONTRIBUTOR,"fascinatingly, telling python to open sqlite in read only mode makes this layer have a size of 0
```python
# test_sql_ro.py
import sqlite3
import sys
db_name = sys.argv[1]
conn = sqlite3.connect(f'file:/app/{db_name}?mode=ro', uri=True)
cur = conn.cursor()
cur.execute('select count(*) from filing')
print(cur.fetchone())
```
that's quite weird because setting the file permissions to read only didn't do anything. (on reflection, that chmod isn't doing anything because the dockerfile commands are run as root)","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1270988081,https://api.github.com/repos/simonw/datasette/issues/1836,1270988081,IC_kwDOBm6k_c5Lwb0x,536941,2022-10-07T01:19:01Z,2022-10-07T01:27:35Z,CONTRIBUTOR,"okay, some progress!! running some sql against a database file causes that file to get duplicated even if it doesn't apparently change the file.
make a little test script like this:
```python
# test_sql.py
import sqlite3
import sys
db_name = sys.argv[1]
conn = sqlite3.connect(f'file:/app/{db_name}', uri=True)
cur = conn.cursor()
cur.execute('select count(*) from filing')
print(cur.fetchone())
```
then
```docker
RUN python test_sql.py nlrb.db
```
produced a layer that's the same size as `nlrb.db`!!
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1270936982,https://api.github.com/repos/simonw/datasette/issues/1836,1270936982,IC_kwDOBm6k_c5LwPWW,536941,2022-10-07T00:52:41Z,2022-10-07T00:52:41Z,CONTRIBUTOR,"it's not that the inspect command is somehow changing the db files. if i set them to only read-only, the ""inspect"" layer still has the same very large size.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,
https://github.com/simonw/datasette/issues/1836#issuecomment-1270923537,https://api.github.com/repos/simonw/datasette/issues/1836,1270923537,IC_kwDOBm6k_c5LwMER,536941,2022-10-07T00:46:08Z,2022-10-07T00:46:08Z,CONTRIBUTOR,"i thought it was maybe to do with reading through all the files, but that does not seem to be the case
if i make a little test file like:
```python
# test_read.py
import hashlib
import sys
import pathlib
HASH_BLOCK_SIZE = 1024 * 1024
def inspect_hash(path):
""""""Calculate the hash of a database, efficiently.""""""
m = hashlib.sha256()
with path.open(""rb"") as fp:
while True:
data = fp.read(HASH_BLOCK_SIZE)
if not data:
break
m.update(data)
return m.hexdigest()
inspect_hash(pathlib.Path(sys.argv[1]))
```
then a line in the Dockerfile like
```docker
RUN python test_read.py nlrb.db && echo ""[]"" > /etc/inspect.json
```
just produes a layer of `3B`
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",1400374908,