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journal: fix skipping of duplicate entries in iteration

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I accidentally broke the detection of duplicate entries in 7943f42275
"journal: optimize iteration by returning previously found candidate
entry".

When we have a known location of a candidate entry, we must not return
from next_beyond_location() immediately. We must go through the
duplicates detection to make sure the candidate differs from the
already iterated entry.

This fix slows down iteration a bit, but it's still faster than it
was before the rework.

$ time ./journalctl --since=2014-06-01 --until=2014-07-01 > /dev/null

real    0m4.448s
user    0m4.298s
sys     0m0.149s

(Compare with results from commit 7943f42275, where real was 5.3s before
the rework.)
This commit is contained in:
Michal Schmidt
2014-12-19 15:37:10 +01:00
parent bfcdba8d56
commit 487d37209b
1 changed files with 30 additions and 36 deletions
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src/journal/sd-journal.c
+30 -36
View File
@@ -412,60 +412,51 @@ _public_ void sd_journal_flush_matches(sd_journal *j) {
detach_location(j);
}
_pure_ static int compare_with_location(JournalFile *af, Object *ao, Location *l) {
uint64_t a;
assert(af);
assert(ao);
_pure_ static int compare_with_location(JournalFile *f, Location *l) {
assert(f);
assert(l);
assert(f->location_type == LOCATION_SEEK);
assert(l->type == LOCATION_DISCRETE || l->type == LOCATION_SEEK);
if (l->monotonic_set &&
sd_id128_equal(ao->entry.boot_id, l->boot_id) &&
sd_id128_equal(f->current_boot_id, l->boot_id) &&
l->realtime_set &&
le64toh(ao->entry.realtime) == l->realtime &&
f->current_realtime == l->realtime &&
l->xor_hash_set &&
le64toh(ao->entry.xor_hash) == l->xor_hash)
f->current_xor_hash == l->xor_hash)
return 0;
if (l->seqnum_set &&
sd_id128_equal(af->header->seqnum_id, l->seqnum_id)) {
sd_id128_equal(f->header->seqnum_id, l->seqnum_id)) {
a = le64toh(ao->entry.seqnum);
if (a < l->seqnum)
if (f->current_seqnum < l->seqnum)
return -1;
if (a > l->seqnum)
if (f->current_seqnum > l->seqnum)
return 1;
}
if (l->monotonic_set &&
sd_id128_equal(ao->entry.boot_id, l->boot_id)) {
sd_id128_equal(f->current_boot_id, l->boot_id)) {
a = le64toh(ao->entry.monotonic);
if (a < l->monotonic)
if (f->current_monotonic < l->monotonic)
return -1;
if (a > l->monotonic)
if (f->current_monotonic > l->monotonic)
return 1;
}
if (l->realtime_set) {
a = le64toh(ao->entry.realtime);
if (a < l->realtime)
if (f->current_realtime < l->realtime)
return -1;
if (a > l->realtime)
if (f->current_realtime > l->realtime)
return 1;
}
if (l->xor_hash_set) {
a = le64toh(ao->entry.xor_hash);
if (a < l->xor_hash)
if (f->current_xor_hash < l->xor_hash)
return -1;
if (a > l->xor_hash)
if (f->current_xor_hash > l->xor_hash)
return 1;
}
@@ -740,21 +731,24 @@ static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direc
f->last_n_entries = n_entries;
if (f->last_direction == direction && f->current_offset > 0) {
cp = f->current_offset;
/* LOCATION_SEEK here means we did the work in a previous
* iteration and the current location already points to a
* candidate entry. */
if (f->location_type == LOCATION_SEEK)
return 1;
if (f->location_type != LOCATION_SEEK) {
r = next_with_matches(j, f, direction, &c, &cp);
if (r <= 0)
return r;
cp = f->current_offset;
r = next_with_matches(j, f, direction, &c, &cp);
if (r <= 0)
return r;
journal_file_save_location(f, direction, c, cp);
}
} else {
r = find_location_with_matches(j, f, direction, &c, &cp);
if (r <= 0)
return r;
journal_file_save_location(f, direction, c, cp);
}
/* OK, we found the spot, now let's advance until an entry
@@ -769,20 +763,20 @@ static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direc
if (j->current_location.type == LOCATION_DISCRETE) {
int k;
k = compare_with_location(f, c, &j->current_location);
k = compare_with_location(f, &j->current_location);
found = direction == DIRECTION_DOWN ? k > 0 : k < 0;
} else
found = true;
if (found) {
journal_file_save_location(f, direction, c, cp);
if (found)
return 1;
}
r = next_with_matches(j, f, direction, &c, &cp);
if (r <= 0)
return r;
journal_file_save_location(f, direction, c, cp);
}
}