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114 lines
5.2 KiB
114 lines
5.2 KiB
From 0ad01db952718d3437fa8f077a065d17efe5279b Mon Sep 17 00:00:00 2001 |
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From: Michal Schmidt <mschmidt@redhat.com> |
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Date: Tue, 24 Feb 2015 19:45:17 +0100 |
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Subject: [PATCH] journal: make skipping of exhausted journal files effective |
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again |
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Commit 668c965af "journal: skipping of exhausted journal files is bad if |
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direction changed" fixed a correctness issue, but it also significantly |
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limited the cases where the optimization that skips exhausted journal |
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files could apply. |
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As a result, some journalctl queries are much slower in v219 than in v218. |
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(e.g. queries where a "--since" cutoff should have quickly eliminated |
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older journal files from consideration, but didn't.) |
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If already in the initial iteration find_location_with_matches() finds |
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no entry, the journal file's location is not updated. This is fine, |
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except that: |
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- We must update at least f->last_direction. The optimization relies on |
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it. Let's separate that from journal_file_save_location() and update |
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it immediately after the direction checks. |
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- The optimization was conditional on "f->current_offset > 0", but it |
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would always be 0 in this scenario. This check is unnecessary for the |
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optimization. |
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(cherry picked from commit 950c07d421c04e5aae99973479f4f13131fb45e1) |
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--- |
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src/journal/journal-file.c | 3 +-- |
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src/journal/journal-file.h | 2 +- |
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src/journal/sd-journal.c | 24 +++++++++++++++--------- |
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3 files changed, 17 insertions(+), 12 deletions(-) |
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diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c |
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index 0f28718b0e..24c49b916a 100644 |
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--- a/src/journal/journal-file.c |
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+++ b/src/journal/journal-file.c |
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@@ -2014,8 +2014,7 @@ void journal_file_reset_location(JournalFile *f) { |
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f->current_xor_hash = 0; |
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} |
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-void journal_file_save_location(JournalFile *f, direction_t direction, Object *o, uint64_t offset) { |
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- f->last_direction = direction; |
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+void journal_file_save_location(JournalFile *f, Object *o, uint64_t offset) { |
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f->location_type = LOCATION_SEEK; |
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f->current_offset = offset; |
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f->current_seqnum = le64toh(o->entry.seqnum); |
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diff --git a/src/journal/journal-file.h b/src/journal/journal-file.h |
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index 2526e14d65..403c8f760c 100644 |
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--- a/src/journal/journal-file.h |
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+++ b/src/journal/journal-file.h |
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@@ -199,7 +199,7 @@ int journal_file_find_field_object(JournalFile *f, const void *field, uint64_t s |
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int journal_file_find_field_object_with_hash(JournalFile *f, const void *field, uint64_t size, uint64_t hash, Object **ret, uint64_t *offset); |
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void journal_file_reset_location(JournalFile *f); |
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-void journal_file_save_location(JournalFile *f, direction_t direction, Object *o, uint64_t offset); |
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+void journal_file_save_location(JournalFile *f, Object *o, uint64_t offset); |
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int journal_file_compare_locations(JournalFile *af, JournalFile *bf); |
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int journal_file_next_entry(JournalFile *f, uint64_t p, direction_t direction, Object **ret, uint64_t *offset); |
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diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c |
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index 94891cdf35..9b57e5945d 100644 |
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--- a/src/journal/sd-journal.c |
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+++ b/src/journal/sd-journal.c |
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@@ -723,13 +723,17 @@ static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direc |
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assert(j); |
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assert(f); |
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- if (f->last_direction == direction && f->current_offset > 0) { |
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- /* If we hit EOF before, recheck if any new entries arrived. */ |
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- n_entries = le64toh(f->header->n_entries); |
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- if (f->location_type == LOCATION_TAIL && n_entries == f->last_n_entries) |
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- return 0; |
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- f->last_n_entries = n_entries; |
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+ n_entries = le64toh(f->header->n_entries); |
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+ |
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+ /* If we hit EOF before, we don't need to look into this file again |
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+ * unless direction changed or new entries appeared. */ |
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+ if (f->last_direction == direction && f->location_type == LOCATION_TAIL && |
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+ n_entries == f->last_n_entries) |
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+ return 0; |
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+ f->last_n_entries = n_entries; |
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+ |
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+ if (f->last_direction == direction && f->current_offset > 0) { |
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/* LOCATION_SEEK here means we did the work in a previous |
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* iteration and the current location already points to a |
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* candidate entry. */ |
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@@ -738,14 +742,16 @@ static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direc |
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if (r <= 0) |
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return r; |
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- journal_file_save_location(f, direction, c, cp); |
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+ journal_file_save_location(f, c, cp); |
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} |
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} else { |
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+ f->last_direction = direction; |
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+ |
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r = find_location_with_matches(j, f, direction, &c, &cp); |
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if (r <= 0) |
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return r; |
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- journal_file_save_location(f, direction, c, cp); |
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+ journal_file_save_location(f, c, cp); |
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} |
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/* OK, we found the spot, now let's advance until an entry |
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@@ -773,7 +779,7 @@ static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direc |
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if (r <= 0) |
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return r; |
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- journal_file_save_location(f, direction, c, cp); |
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+ journal_file_save_location(f, c, cp); |
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} |
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} |
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