Slowness (search opens every email file?)

Slowness (search opens every email file?)

[Jason Woofenden]

Hi all,

I'm having a great time patching up the vim frontend, but I've got
an issue that is in the backend, and seems far above my head at
this point:

notmuch search tag:foo is slow!

(when my e-mail files are not already in the disk cache)

I saw on my activity monitor applet that it was using mostly i/o,
and started to wonder if it was opening every e-mail. I little work
with strace and searching revealed that this command was opening
many many e-mail files from my maildir(s). I spent a little while
digging around in the notmuch source, and didn't see where it was
opening the email files.

I don't think the search command should be opening the files. So my
questions:

1) Why is it opening the e-mail files? What information is being
read?

2) Do you agree that it should instead get this information from
the database?

3) How hard would it be make this fast? What would it take?

4) Who wants to do it?


I'd like it to be able to spit out 1000 threads in under a second.
Preferably under 100ms.


Thank you,    -- Jason


P.S. I mean really slow... 

notmuch search tag:foo  took  0.5 seconds for 32 threads

notmuch search foo took 6.4 seconds for 130 threads

Everything's getting into my cache, so I can't easily get lots of
numbers. For a while I had a simple search (tag:foo and tag:bar)
which returned about 600 threads, and it would frequently take
seconds.

Re: Slowness (search opens every email file?)

[Patrick Totzke]

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Hi Jason,
On Mon, Jul 11, 2011 at 03:07:21PM -0400, Jason Woofenden wrote:
> notmuch search tag:foo is slow!
> 
yes, i've just used the vim ui for the first time and i agreee, its sluggish,
searching for * takes a while.

> (when my e-mail files are not already in the disk cache)
> 
> I saw on my activity monitor applet that it was using mostly i/o,
> and started to wonder if it was opening every e-mail. I little work
> with strace and searching revealed that this command was opening
> many many e-mail files from my maildir(s). I spent a little while
> digging around in the notmuch source, and didn't see where it was
> opening the email files.

I cannot reproduce this. I'm no expert, but at least the output of 
 strace vim -c ":NotMuch" 2>log
does not contain any path that matches that of my maildir.
Also, I wout be surprised if all individual mails would be read,
because for this, a search for all messages feels too fast.

> 2) Do you agree that it should instead get this information from
> the database?
agreed. And If the mail files get read on every search for you,
something is definately going wrong there.

A quick browse through notmuch.vim tells me that 
1) it doesn't use notmuchs json output, i think it should, as iirc
this api is considered 'more stable' and is easier to parse than the 
default output. More importantly,
2) the output of notmuch is copied into a list. This will of course
be slow if your query matches a lot of messages. Could this be done
by asyncronously writing to the buffer somehow?

best,
/p

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Re: Slowness (search opens every email file?)

[Jason Woofenden]

On 2011-07-11 10:58PM, Patrick Totzke wrote:
> Hi Jason,
> On Mon, Jul 11, 2011 at 03:07:21PM -0400, Jason Woofenden wrote:
> > notmuch search tag:foo is slow!
> > 
> yes, i've just used the vim ui for the first time and i agreee, its sluggish,
> searching for * takes a while.

It's not the vim ui that's the bottleneck. The underlying notmuch
search command is slow. I gave examples in my last e-mail:

>> notmuch search tag:foo  took  0.5 seconds for 32 threads
>> 
>> notmuch search foo took 6.4 seconds for 130 threads


> > (when my e-mail files are not already in the disk cache)
> > 
> > I saw on my activity monitor applet that it was using mostly i/o,
> > and started to wonder if it was opening every e-mail. I little work
> > with strace and searching revealed that this command was opening
> > many many e-mail files from my maildir(s). I spent a little while
> > digging around in the notmuch source, and didn't see where it was
> > opening the email files.
> 
> I cannot reproduce this. I'm no expert, but at least the output of 
>  strace vim -c ":NotMuch" 2>log

:NotMuch just shows the mailboxes. that's fast. It's showing the
contents that is slow. And it's not vim, it's because the notmuch
command is slow. Try this in a terminal:

strace notmuch search tag:flagged 2>&1 | grep 'open(.*/cur/'

Of course change the tag if you don't have flagged messages.


> A quick browse through notmuch.vim tells me that 
> 1) it doesn't use notmuchs json output, i think it should, as iirc
> this api is considered 'more stable' and is easier to parse than the 
> default output. More importantly,

I like this idea. I did some work earlier on improving the message
parsing in the vim ui. Might be better to use the json. I'll look
into json parsing in vim.


> 2) the output of notmuch is copied into a list. This will of course
> be slow if your query matches a lot of messages. Could this be done
> by asyncronously writing to the buffer somehow?

I'm pretty sure vim doesn't do asynchronous anything. That came up
in a vim vs emacs article I read.


Take care,   - Jason

Re: Slowness (search opens every email file?)

[Austin Clements]

On Mon, Jul 11, 2011 at 3:07 PM, Jason Woofenden <jason@jasonwoof.com> wrote:
> notmuch search tag:foo is slow!
>
> (when my e-mail files are not already in the disk cache)
>
> I saw on my activity monitor applet that it was using mostly i/o,
> and started to wonder if it was opening every e-mail. I little work
> with strace and searching revealed that this command was opening
> many many e-mail files from my maildir(s). I spent a little while
> digging around in the notmuch source, and didn't see where it was
> opening the email files.

It is opening every file to get a few headers to display in the search
output.  Istvan Marko sent an experimental patch to store these
headers in the database a while ago, though as far as I know there
hasn't been any progress cleaning it up for inclusion:
id:"m3sjsv2kw2.fsf@zsu.kismala.com" .

Re: Slowness (search opens every email file?)

[Jason Woofenden]

On 2011-07-11 06:13PM, Austin Clements wrote:
> On Mon, Jul 11, 2011 at 3:07 PM, Jason Woofenden <jason@jasonwoof.com> wrote:
> > notmuch search tag:foo is slow!
> >
> > (when my e-mail files are not already in the disk cache)
> >
> > I saw on my activity monitor applet that it was using mostly i/o,
> > and started to wonder if it was opening every e-mail. I little work
> > with strace and searching revealed that this command was opening
> > many many e-mail files from my maildir(s). I spent a little while
> > digging around in the notmuch source, and didn't see where it was
> > opening the email files.
> 
> It is opening every file to get a few headers to display in the search
> output.  Istvan Marko sent an experimental patch to store these
> headers in the database a while ago, though as far as I know there
> hasn't been any progress cleaning it up for inclusion:
> id:"m3sjsv2kw2.fsf@zsu.kismala.com" .

Cool. I suspected it was reading for header files.

I googled the id and found this patchwork link:

http://patchwork.notmuchmail.org/patch/947/

(I didn't see any way to ask mailman for a message id.)

Does someone want to work at this soon or should I try my hand at
it?


Thanks,     - Jason

Get mboxes from mailman [Was: Slowness (search opens every email file?)]

[Uwe Kleine-König]

Hello,

On Tue, Jul 12, 2011 at 04:24:59PM -0400, Jason Woofenden wrote:
> (I didn't see any way to ask mailman for a message id.)
It's possible to let mailman offer mbox downloads parallel to the
"Gzip'd Text" files.

You need to set

	PUBLIC_MBOX = Yes;

in your mailman config and restart mailman (i.e. mailmanctl restart).

Best regards
Uwe

Re: Slowness (search opens every email file?)

[Austin Clements]

On Tue, Jul 12, 2011 at 4:24 PM, Jason Woofenden <jason@jasonwoof.com> wrote:
> On 2011-07-11 06:13PM, Austin Clements wrote:
>> On Mon, Jul 11, 2011 at 3:07 PM, Jason Woofenden <jason@jasonwoof.com> wrote:
>> > notmuch search tag:foo is slow!
>> >
>> > (when my e-mail files are not already in the disk cache)
>> >
>> > I saw on my activity monitor applet that it was using mostly i/o,
>> > and started to wonder if it was opening every e-mail. I little work
>> > with strace and searching revealed that this command was opening
>> > many many e-mail files from my maildir(s). I spent a little while
>> > digging around in the notmuch source, and didn't see where it was
>> > opening the email files.
>>
>> It is opening every file to get a few headers to display in the search
>> output.  Istvan Marko sent an experimental patch to store these
>> headers in the database a while ago, though as far as I know there
>> hasn't been any progress cleaning it up for inclusion:
>> id:"m3sjsv2kw2.fsf@zsu.kismala.com" .
>
> Cool. I suspected it was reading for header files.
>
> I googled the id and found this patchwork link:
>
> http://patchwork.notmuchmail.org/patch/947/
>
> (I didn't see any way to ask mailman for a message id.)

Here's the full thread from Nabble:
http://notmuch.198994.n3.nabble.com/storing-From-and-Subject-in-xapian-td2901262.html

> Does someone want to work at this soon or should I try my hand at
> it?

Istvan, did you make any progress on this patch since the last
version?  I seem to recall it just needed general cleanup (code style
and such) and a better answer for backwards compatibility (the
unfortunate " " thing).

Re: Slowness (search opens every email file?)

[Istvan Marko]

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Austin Clements <amdragon-3s7WtUTddSA@public.gmane.org> writes:

> Istvan, did you make any progress on this patch since the last
> version?  I seem to recall it just needed general cleanup (code style
> and such) and a better answer for backwards compatibility (the
> unfortunate " " thing).

I have been using the version that encodes empty headers to " " but
another way to handle this is to simply not set a VALUE for empty
headers and then fall back to the original parsing method for these
messages. Emails without from/subject/message-id headers are not very
common so perhaps this is a good compromise.

Below is the patch without the " " hack.


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[-- Attachment #2: notmuch-value2.patch --]
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diff --git a/lib/database.cc b/lib/database.cc
index 9c2f4ec..63a15bb 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -1654,7 +1654,7 @@ notmuch_database_add_message (notmuch_database_t *notmuch,
 		goto DONE;
 
 	    date = notmuch_message_file_get_header (message_file, "date");
-	    _notmuch_message_set_date (message, date);
+	    _notmuch_message_set_header_values (message, date, from, subject);
 
 	    _notmuch_message_index_file (message, filename);
 	} else {
diff --git a/lib/message.cc b/lib/message.cc
index d993cde..48a31f5 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -410,6 +410,20 @@ _notmuch_message_ensure_message_file (notmuch_message_t *message)
 const char *
 notmuch_message_get_header (notmuch_message_t *message, const char *header)
 {
+    std::string value;
+
+    // fetch header from the appropriate xapian value field if available
+    if (strcmp(header,"from") == 0)
+        value=message->doc.get_value(NOTMUCH_VALUE_FROM);
+    else if (strcmp(header,"subject") == 0)
+        value=message->doc.get_value (NOTMUCH_VALUE_SUBJECT);
+    else if (strcmp(header,"message-id") == 0)
+	value=message->doc.get_value (NOTMUCH_VALUE_MESSAGE_ID);
+
+    if (!value.empty())
+	return talloc_strdup (message, value.c_str ());
+
+    // otherwise fall back to parsing the file
     _notmuch_message_ensure_message_file (message);
     if (message->message_file == NULL)
 	return NULL;
@@ -785,8 +799,10 @@ notmuch_message_set_author (notmuch_message_t *message,
 }
 
 void
-_notmuch_message_set_date (notmuch_message_t *message,
-			   const char *date)
+_notmuch_message_set_header_values (notmuch_message_t *message,
+				    const char *date,
+				    const char *from,
+				    const char *subject)
 {
     time_t time_value;
 
@@ -799,6 +815,8 @@ _notmuch_message_set_date (notmuch_message_t *message,
 
     message->doc.add_value (NOTMUCH_VALUE_TIMESTAMP,
 			    Xapian::sortable_serialise (time_value));
+    message->doc.add_value (NOTMUCH_VALUE_FROM, from);
+    message->doc.add_value (NOTMUCH_VALUE_SUBJECT, subject);
 }
 
 /* Synchronize changes made to message->doc out into the database. */
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 02e24ee..2e91afd 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -111,7 +111,9 @@ _internal_error (const char *format, ...) PRINTF_ATTRIBUTE (1, 2);
 
 typedef enum {
     NOTMUCH_VALUE_TIMESTAMP = 0,
-    NOTMUCH_VALUE_MESSAGE_ID
+    NOTMUCH_VALUE_MESSAGE_ID,
+    NOTMUCH_VALUE_FROM,
+    NOTMUCH_VALUE_SUBJECT
 } notmuch_value_t;
 
 /* Xapian (with flint backend) complains if we provide a term longer
@@ -287,9 +289,10 @@ void
 _notmuch_message_ensure_thread_id (notmuch_message_t *message);
 
 void
-_notmuch_message_set_date (notmuch_message_t *message,
-			   const char *date);
-
+_notmuch_message_set_header_values (notmuch_message_t *message,
+				    const char *date,
+				    const char *from,
+				    const char *subject);
 void
 _notmuch_message_sync (notmuch_message_t *message);
 

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-- 
	Istvan

Re: Slowness (search opens every email file?)

[Austin Clements]

Quoth Istvan Marko on Jul 12 at  6:55 pm:
> Austin Clements <amdragon-3s7WtUTddSA@public.gmane.org> writes:
> 
> > Istvan, did you make any progress on this patch since the last
> > version?  I seem to recall it just needed general cleanup (code style
> > and such) and a better answer for backwards compatibility (the
> > unfortunate " " thing).
> 
> I have been using the version that encodes empty headers to " " but
> another way to handle this is to simply not set a VALUE for empty
> headers and then fall back to the original parsing method for these
> messages. Emails without from/subject/message-id headers are not very
> common so perhaps this is a good compromise.
> 
> Below is the patch without the " " hack.

Ah, clever.  I was going to suggest adding another value to indicate
the presence or absence of these Xapian values, but I like your
solution better.  The only downside I can think of is that it might
not extend to other headers if we store more header values in the
database in the future.

I'd say this patch looks good other than coding style
- Tab indentation
- /* */ comments, starting with a capital letter
- Space between function name and open paren
- Space after comma in argument lists
- Spaces around assignment operator

Re: Slowness (search opens every email file?)

[Istvan Marko]

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Austin Clements <amdragon@MIT.EDU> writes:

> I'd say this patch looks good other than coding style
> - Tab indentation
> - /* */ comments, starting with a capital letter
> - Space between function name and open paren
> - Space after comma in argument lists
> - Spaces around assignment operator

Thanks, fixed the ones I see:


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diff --git a/lib/database.cc b/lib/database.cc
index 9c2f4ec..63a15bb 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -1654,7 +1654,7 @@ notmuch_database_add_message (notmuch_database_t *notmuch,
 		goto DONE;
 
 	    date = notmuch_message_file_get_header (message_file, "date");
-	    _notmuch_message_set_date (message, date);
+	    _notmuch_message_set_header_values (message, date, from, subject);
 
 	    _notmuch_message_index_file (message, filename);
 	} else {
diff --git a/lib/message.cc b/lib/message.cc
index d993cde..55070c6 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -410,6 +410,21 @@ _notmuch_message_ensure_message_file (notmuch_message_t *message)
 const char *
 notmuch_message_get_header (notmuch_message_t *message, const char *header)
 {
+    std::string value;
+
+    /* Fetch header from the appropriate xapian value field if
+     * available */
+    if (strcmp(header, "from") == 0)
+	value = message->doc.get_value(NOTMUCH_VALUE_FROM);
+    else if (strcmp(header, "subject") == 0)
+	value = message->doc.get_value (NOTMUCH_VALUE_SUBJECT);
+    else if (strcmp(header, "message-id") == 0)
+	value = message->doc.get_value (NOTMUCH_VALUE_MESSAGE_ID);
+
+    if (!value.empty())
+	return talloc_strdup (message, value.c_str ());
+
+    /* Otherwise fall back to parsing the file */
     _notmuch_message_ensure_message_file (message);
     if (message->message_file == NULL)
 	return NULL;
@@ -785,8 +800,10 @@ notmuch_message_set_author (notmuch_message_t *message,
 }
 
 void
-_notmuch_message_set_date (notmuch_message_t *message,
-			   const char *date)
+_notmuch_message_set_header_values (notmuch_message_t *message,
+				    const char *date,
+				    const char *from,
+				    const char *subject)
 {
     time_t time_value;
 
@@ -799,6 +816,8 @@ _notmuch_message_set_date (notmuch_message_t *message,
 
     message->doc.add_value (NOTMUCH_VALUE_TIMESTAMP,
 			    Xapian::sortable_serialise (time_value));
+    message->doc.add_value (NOTMUCH_VALUE_FROM, from);
+    message->doc.add_value (NOTMUCH_VALUE_SUBJECT, subject);
 }
 
 /* Synchronize changes made to message->doc out into the database. */
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 02e24ee..2e91afd 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -111,7 +111,9 @@ _internal_error (const char *format, ...) PRINTF_ATTRIBUTE (1, 2);
 
 typedef enum {
     NOTMUCH_VALUE_TIMESTAMP = 0,
-    NOTMUCH_VALUE_MESSAGE_ID
+    NOTMUCH_VALUE_MESSAGE_ID,
+    NOTMUCH_VALUE_FROM,
+    NOTMUCH_VALUE_SUBJECT
 } notmuch_value_t;
 
 /* Xapian (with flint backend) complains if we provide a term longer
@@ -287,9 +289,10 @@ void
 _notmuch_message_ensure_thread_id (notmuch_message_t *message);
 
 void
-_notmuch_message_set_date (notmuch_message_t *message,
-			   const char *date);
-
+_notmuch_message_set_header_values (notmuch_message_t *message,
+				    const char *date,
+				    const char *from,
+				    const char *subject);
 void
 _notmuch_message_sync (notmuch_message_t *message);
 

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-- 
	Istvan

Re: Slowness (search opens every email file?)

[Austin Clements]

Quoth Istvan Marko on Jul 12 at  8:07 pm:
> Austin Clements <amdragon@MIT.EDU> writes:
> 
> > I'd say this patch looks good other than coding style
> > - Tab indentation
> > - /* */ comments, starting with a capital letter
> > - Space between function name and open paren
> > - Space after comma in argument lists
> > - Spaces around assignment operator
> 
> Thanks, fixed the ones I see:

+    /* Fetch header from the appropriate xapian value field if
+     * available */
+    if (strcmp(header, "from") == 0)
+       value = message->doc.get_value(NOTMUCH_VALUE_FROM);
+    else if (strcmp(header, "subject") == 0)
+       value = message->doc.get_value (NOTMUCH_VALUE_SUBJECT);
+    else if (strcmp(header, "message-id") == 0)
+       value = message->doc.get_value (NOTMUCH_VALUE_MESSAGE_ID);

The strcmp's should have a space before the paren, as should the first
get_value.  (Yeah, it's weird.  Blame glib.)

Also, it occurred to me that these should be strcasecmp's, since
headers are case-insensitive.