* [tarantool-patches] [PATCH] xlog: added request details to panic message for broken LSN
@ 2018-08-09 15:02 Sergei Kalashnikov
2018-08-14 16:17 ` Vladimir Davydov
0 siblings, 1 reply; 2+ messages in thread
From: Sergei Kalashnikov @ 2018-08-09 15:02 UTC (permalink / raw)
To: tarantool-patches
Aid the debugging of replication issues related to out-of-order requests.
Adds the details of request/tuple to the diagnostic message whenever possible.
Fixes: #3105
---
Ticket:https://github.com/tarantool/tarantool/issues/3105
Branch:ztarvos/gh-3105-log-request-broken-lsn
src/box/applier.cc | 8 +-
src/box/recovery.cc | 4 +-
src/box/vclock.c | 6 +
src/box/vclock.h | 22 +++
src/box/wal.c | 12 +-
src/box/xrow.c | 24 +++
src/box/xrow.h | 15 ++
test/xlog/log_request_broken_lsn_panic.result | 200 ++++++++++++++++++++++++
test/xlog/log_request_broken_lsn_panic.test.lua | 105 +++++++++++++
test/xlog/panic_broken_lsn.lua | 11 ++
10 files changed, 395 insertions(+), 12 deletions(-)
create mode 100644 test/xlog/log_request_broken_lsn_panic.result
create mode 100644 test/xlog/log_request_broken_lsn_panic.test.lua
create mode 100644 test/xlog/panic_broken_lsn.lua
diff --git a/src/box/applier.cc b/src/box/applier.cc
index dbb4d05..108f657 100644
--- a/src/box/applier.cc
+++ b/src/box/applier.cc
@@ -336,8 +336,8 @@ applier_join(struct applier *applier)
coio_read_xrow(coio, ibuf, &row);
applier->last_row_time = ev_monotonic_now(loop());
if (iproto_type_is_dml(row.type)) {
- vclock_follow(&replicaset.vclock, row.replica_id,
- row.lsn);
+ xrow_vclock_follow(&replicaset.vclock, row.replica_id,
+ row.lsn, &row);
xstream_write_xc(applier->subscribe_stream, &row);
} else if (row.type == IPROTO_OK) {
/*
@@ -503,8 +503,8 @@ applier_subscribe(struct applier *applier)
* the row is skipped when the replication
* is resumed.
*/
- vclock_follow(&replicaset.vclock, row.replica_id,
- row.lsn);
+ vclock_follow_unsafe(&replicaset.vclock, row.replica_id,
+ row.lsn);
struct replica *replica = replica_by_id(row.replica_id);
struct latch *latch = (replica ? &replica->order_latch :
&replicaset.applier.order_latch);
diff --git a/src/box/recovery.cc b/src/box/recovery.cc
index fe14def..c3eac62 100644
--- a/src/box/recovery.cc
+++ b/src/box/recovery.cc
@@ -135,7 +135,7 @@ recovery_scan(struct recovery *r, struct vclock *end_vclock)
return;
struct xrow_header row;
while (xlog_cursor_next(&cursor, &row, true) == 0)
- vclock_follow(end_vclock, row.replica_id, row.lsn);
+ xrow_vclock_follow(end_vclock, row.replica_id, row.lsn, &row);
xlog_cursor_close(&cursor, false);
}
@@ -266,7 +266,7 @@ recover_xlog(struct recovery *r, struct xstream *stream,
* in case of forced recovery, when we skip the
* failed row anyway.
*/
- vclock_follow(&r->vclock, row.replica_id, row.lsn);
+ vclock_follow_unsafe(&r->vclock, row.replica_id, row.lsn);
if (xstream_write(stream, &row) == 0) {
++row_count;
if (row_count % 100000 == 0)
diff --git a/src/box/vclock.c b/src/box/vclock.c
index 2189ea8..a8f2d99 100644
--- a/src/box/vclock.c
+++ b/src/box/vclock.c
@@ -49,6 +49,12 @@ vclock_follow(struct vclock *vclock, uint32_t
replica_id, int64_t lsn)
(unsigned) replica_id,
(long long) prev_lsn, (long long) lsn);
}
+ return vclock_follow_unsafe(vclock, replica_id, lsn);
+}
+
+int64_t
+vclock_follow_unsafe(struct vclock *vclock, uint32_t replica_id, int64_t lsn) {
+ int64_t prev_lsn = vclock->lsn[replica_id];
/* Easier add each time than check. */
vclock->map |= 1 << replica_id;
vclock->lsn[replica_id] = lsn;
diff --git a/src/box/vclock.h b/src/box/vclock.h
index 928717c..e389074 100644
--- a/src/box/vclock.h
+++ b/src/box/vclock.h
@@ -199,10 +199,32 @@ vclock_sum(const struct vclock *vclock)
return vclock->signature;
}
+/**
+ * Update vclock with the next LSN value for given replica id.
+ * The function will cause panic if the next LSN happens to be
+ * out of order.
+ *
+ * @param vclock Vector clock.
+ * @param replica_id Replica identifier.
+ * @param lsn Next lsn.
+ */
int64_t
vclock_follow(struct vclock *vclock, uint32_t replica_id, int64_t lsn);
/**
+ * Update vclock with the next LSN value for given replica id.
+ * No checks are performed by this function. It may only be
+ * used when prior checks are performed with regard to validity
+ * of its parameters.
+ *
+ * @param vclock Vector clock.
+ * @param replica_id Replica identifier.
+ * @param lsn Next lsn.
+ */
+int64_t
+vclock_follow_unsafe(struct vclock *vclock, uint32_t replica_id, int64_t lsn);
+
+/**
* \brief Format vclock to YAML-compatible string representation:
* { replica_id: lsn, replica_id:lsn })
* \param vclock vclock
diff --git a/src/box/wal.c b/src/box/wal.c
index 41762a5..b206cb0 100644
--- a/src/box/wal.c
+++ b/src/box/wal.c
@@ -662,8 +662,8 @@ wal_assign_lsn(struct wal_writer *writer, struct
xrow_header **row,
(*row)->lsn = vclock_inc(&writer->vclock, instance_id);
(*row)->replica_id = instance_id;
} else {
- vclock_follow(&writer->vclock, (*row)->replica_id,
- (*row)->lsn);
+ xrow_vclock_follow(&writer->vclock, (*row)->replica_id,
+ (*row)->lsn, *row);
}
}
}
@@ -888,9 +888,9 @@ wal_write(struct journal *journal, struct
journal_entry *entry)
*/
if (vclock_get(&replicaset.vclock,
instance_id) < (*last)->lsn) {
- vclock_follow(&replicaset.vclock,
- instance_id,
- (*last)->lsn);
+ vclock_follow_unsafe(&replicaset.vclock,
+ instance_id,
+ (*last)->lsn);
}
break;
}
@@ -910,7 +910,7 @@ wal_write_in_wal_mode_none(struct journal *journal,
int64_t new_lsn = vclock_get(&writer->vclock, instance_id);
if (new_lsn > old_lsn) {
/* There were local writes, promote vclock. */
- vclock_follow(&replicaset.vclock, instance_id, new_lsn);
+ vclock_follow_unsafe(&replicaset.vclock, instance_id, new_lsn);
}
return vclock_sum(&writer->vclock);
}
diff --git a/src/box/xrow.c b/src/box/xrow.c
index 269a6e6..558d8d5 100644
--- a/src/box/xrow.c
+++ b/src/box/xrow.c
@@ -1194,3 +1194,27 @@ greeting_decode(const char *greetingbuf, struct
greeting *greeting)
return 0;
}
+
+void
+xrow_vclock_follow(struct vclock* vclock, uint32_t replica_id, int64_t lsn,
+ const struct xrow_header *row) {
+ assert(lsn >= 0);
+ assert(replica_id < VCLOCK_MAX);
+ int64_t prev_lsn = vclock->lsn[replica_id];
+ if (lsn <= prev_lsn) {
+ const char* req_str = NULL;
+ if (row != NULL) {
+ struct request req;
+ if (xrow_decode_dml((struct xrow_header *)row, &req, 0) == 0)
+ req_str = request_str(&req);
+ }
+ /* Never confirm LSN out of order. */
+ panic("LSN for %u is used twice or COMMIT order is broken: "
+ "confirmed: %lld, new: %lld, req: %s",
+ (unsigned) replica_id,
+ (long long) prev_lsn,
+ (long long) lsn,
+ req_str?req_str:"n/a");
+ }
+ vclock_follow_unsafe(vclock, replica_id, lsn);
+}
diff --git a/src/box/xrow.h b/src/box/xrow.h
index 9887382..4f82399 100644
--- a/src/box/xrow.h
+++ b/src/box/xrow.h
@@ -519,6 +519,21 @@ xrow_to_iovec(const struct xrow_header *row,
struct iovec *out);
void
xrow_decode_error(struct xrow_header *row);
+/**
+ * Update vclock with the next LSN value for given replica id.
+ * The function will cause panic if the next LSN happens to be
+ * out of order. The details of provided row are included into
+ * diagnostic message.
+ *
+ * @param vclock Vector clock.
+ * @param replica_id Replica identifier.
+ * @param lsn Next lsn.
+ * @param row Data row.
+ */
+void
+xrow_vclock_follow(struct vclock* vclock, uint32_t replica_id, int64_t lsn,
+ const struct xrow_header *row);
+
#if defined(__cplusplus)
} /* extern "C" */
diff --git a/test/xlog/log_request_broken_lsn_panic.result
b/test/xlog/log_request_broken_lsn_panic.result
new file mode 100644
index 0000000..89bed53
--- /dev/null
+++ b/test/xlog/log_request_broken_lsn_panic.result
@@ -0,0 +1,200 @@
+-- Issue 3105: Test logging of request with broken lsn before panicking
+env = require('test_run')
+---
+...
+test_run = env.new()
+---
+...
+test_run:cmd('create server panic_broken_lsn with
script="xlog/panic_broken_lsn.lua"')
+---
+- true
+...
+test_run:cmd('start server panic_broken_lsn')
+---
+- true
+...
+test_run:switch('panic_broken_lsn')
+---
+- true
+...
+box.space._schema:replace{"t0", "v0"}
+---
+- ['t0', 'v0']
+...
+box.snapshot()
+---
+- ok
+...
+box.space._schema:replace{"t0", "v1"}
+---
+- ['t0', 'v1']
+...
+box.snapshot()
+---
+- ok
+...
+box.space._schema:replace{"t0", "v2"}
+---
+- ['t0', 'v2']
+...
+box.snapshot()
+---
+- ok
+...
+test_run:switch('default')
+---
+- true
+...
+test_run:cmd('stop server panic_broken_lsn')
+---
+- true
+...
+fio = require('fio')
+---
+...
+dirname = fio.pathjoin(fio.cwd(), "panic_broken_lsn")
+---
+...
+xlogs = fio.glob(dirname .. "/*.xlog")
+---
+...
+wal1_name = xlogs[#xlogs - 2]
+---
+...
+wal2_name = xlogs[#xlogs - 1]
+---
+...
+snaps = fio.glob(dirname .. "/*.snap")
+---
+...
+-- Remove empty xlog
+fio.unlink(xlogs[#xlogs])
+---
+- true
+...
+-- Remove two last snapshots
+fio.unlink(snaps[#snaps])
+---
+- true
+...
+fio.unlink(snaps[#snaps - 1])
+---
+- true
+...
+buffer = require('buffer')
+---
+...
+ffi = require('ffi')
+---
+...
+test_run:cmd("setopt delimiter ';'")
+---
+- true
+...
+function read_file(filepath)
+ local fh = fio.open(filepath, {'O_RDONLY'})
+ local size = fh:stat().size
+ local buf = buffer.ibuf()
+ fh:read(buf:reserve(size))
+ fh:close()
+ buf:alloc(size)
+ return buf
+end;
+---
+...
+function find_marker_pos(buf)
+ local sz = buf:size()
+ local data = ffi.string(buf.rpos, sz)
+ local cnt = 0
+ for i = 1, sz do
+ local b = string.byte(data, i)
+ if (cnt == 0 and b == 213) then
+ cnt = 1
+ elseif (cnt == 1 and b == 186) then
+ cnt = 2
+ elseif (cnt == 2 and b == 11) then
+ cnt = 3
+ elseif (cnt == 3 and b == 171) then
+ return i - 3
+ else
+ cnt = 0
+ end
+ end
+ return 0
+end;
+---
+...
+function run_panic()
+ local tarantool_bin = arg[-1]
+ local fmt = [[/bin/sh -c 'cd "%s" && "%s" ../panic_broken_lsn.lua']]
+ local cmd = string.format(fmt, dirname, tarantool_bin)
+ local res = os.execute(cmd)
+ return res
+end;
+---
+...
+test_run:cmd("setopt delimiter ''");
+---
+- true
+...
+-- Read WAL 1 and find position of data
+buf1 = read_file(wal1_name)
+---
+...
+pos1 = find_marker_pos(buf1)
+---
+...
+-- Read WAL 2 and find position of data
+buf2 = read_file(wal2_name)
+---
+...
+pos2 = find_marker_pos(buf2)
+---
+...
+-- Create fake WAL file with header of WAL 2 and data of WAL 1
+tmp_file_name = wal2_name .. ".tmp"
+---
+...
+fh3 = fio.open(tmp_file_name, {'O_WRONLY', 'O_CREAT'})
+---
+...
+fh3:write(buf2.rpos, pos2)
+---
+- true
+...
+fh3:write(buf1.rpos + pos1, buf1:size() - pos1)
+---
+- true
+...
+fh3:close()
+---
+- true
+...
+fio.chmod(tmp_file_name, 0x1B0)
+---
+- true
+...
+-- Replace WAL 2 with fake WAL file
+fio.unlink(wal2_name)
+---
+- true
+...
+fio.copyfile(tmp_file_name, wal2_name)
+---
+- true
+...
+fio.unlink(tmp_file_name)
+---
+- true
+...
+-- Try to start tarantool with xlog containing broken LSN
+run_panic()
+---
+- 256
+...
+-- Check that log contains the mention of broken LSN and the request printout
+test_run:grep_log('default', "LSN for 1 is used twice or COMMIT order
is broken: confirmed: 2, new: 2, req: {.*}")
+---
+- 'LSN for 1 is used twice or COMMIT order is broken: confirmed: 2,
new: 2, req: {type:
+ ''REPLACE'', lsn: 2, space_id: 272, index_id: 0, tuple: ["t0", "v1"]}'
+...
diff --git a/test/xlog/log_request_broken_lsn_panic.test.lua
b/test/xlog/log_request_broken_lsn_panic.test.lua
new file mode 100644
index 0000000..f87024c
--- /dev/null
+++ b/test/xlog/log_request_broken_lsn_panic.test.lua
@@ -0,0 +1,105 @@
+-- Issue 3105: Test logging of request with broken lsn before panicking
+env = require('test_run')
+test_run = env.new()
+
+test_run:cmd('create server panic_broken_lsn with
script="xlog/panic_broken_lsn.lua"')
+test_run:cmd('start server panic_broken_lsn')
+test_run:switch('panic_broken_lsn')
+
+box.space._schema:replace{"t0", "v0"}
+box.snapshot()
+box.space._schema:replace{"t0", "v1"}
+box.snapshot()
+box.space._schema:replace{"t0", "v2"}
+box.snapshot()
+
+test_run:switch('default')
+test_run:cmd('stop server panic_broken_lsn')
+
+fio = require('fio')
+
+dirname = fio.pathjoin(fio.cwd(), "panic_broken_lsn")
+
+xlogs = fio.glob(dirname .. "/*.xlog")
+
+wal1_name = xlogs[#xlogs - 2]
+wal2_name = xlogs[#xlogs - 1]
+
+snaps = fio.glob(dirname .. "/*.snap")
+
+-- Remove empty xlog
+fio.unlink(xlogs[#xlogs])
+
+-- Remove two last snapshots
+fio.unlink(snaps[#snaps])
+fio.unlink(snaps[#snaps - 1])
+
+buffer = require('buffer')
+ffi = require('ffi')
+
+test_run:cmd("setopt delimiter ';'")
+function read_file(filepath)
+ local fh = fio.open(filepath, {'O_RDONLY'})
+ local size = fh:stat().size
+ local buf = buffer.ibuf()
+ fh:read(buf:reserve(size))
+ fh:close()
+ buf:alloc(size)
+ return buf
+end;
+function find_marker_pos(buf)
+ local sz = buf:size()
+ local data = ffi.string(buf.rpos, sz)
+ local cnt = 0
+ for i = 1, sz do
+ local b = string.byte(data, i)
+ if (cnt == 0 and b == 213) then
+ cnt = 1
+ elseif (cnt == 1 and b == 186) then
+ cnt = 2
+ elseif (cnt == 2 and b == 11) then
+ cnt = 3
+ elseif (cnt == 3 and b == 171) then
+ return i - 3
+ else
+ cnt = 0
+ end
+ end
+ return 0
+end;
+function run_panic()
+ local tarantool_bin = arg[-1]
+ local fmt = [[/bin/sh -c 'cd "%s" && "%s" ../panic_broken_lsn.lua']]
+ local cmd = string.format(fmt, dirname, tarantool_bin)
+ local res = os.execute(cmd)
+ return res
+end;
+test_run:cmd("setopt delimiter ''");
+
+-- Read WAL 1 and find position of data
+buf1 = read_file(wal1_name)
+pos1 = find_marker_pos(buf1)
+
+-- Read WAL 2 and find position of data
+buf2 = read_file(wal2_name)
+pos2 = find_marker_pos(buf2)
+
+-- Create fake WAL file with header of WAL 2 and data of WAL 1
+tmp_file_name = wal2_name .. ".tmp"
+
+fh3 = fio.open(tmp_file_name, {'O_WRONLY', 'O_CREAT'})
+fh3:write(buf2.rpos, pos2)
+fh3:write(buf1.rpos + pos1, buf1:size() - pos1)
+fh3:close()
+fio.chmod(tmp_file_name, 0x1B0)
+
+-- Replace WAL 2 with fake WAL file
+fio.unlink(wal2_name)
+fio.copyfile(tmp_file_name, wal2_name)
+fio.unlink(tmp_file_name)
+
+-- Try to start tarantool with xlog containing broken LSN
+run_panic()
+
+-- Check that log contains the mention of broken LSN and the request printout
+test_run:grep_log('default', "LSN for 1 is used twice or COMMIT order
is broken: confirmed: 2, new: 2, req: {.*}")
diff --git a/test/xlog/panic_broken_lsn.lua b/test/xlog/panic_broken_lsn.lua
new file mode 100644
index 0000000..4d869a3
--- /dev/null
+++ b/test/xlog/panic_broken_lsn.lua
@@ -0,0 +1,11 @@
+#!/usr/bin/env tarantool
+os = require('os')
+
+box.cfg{
+ listen = os.getenv("LISTEN"),
+ memtx_memory = 107374182,
+ pid_file = "tarantool.pid",
+ checkpoint_count = 3
+}
+
+require('console').listen(os.getenv('ADMIN'))
--
1.8.3.1
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [tarantool-patches] [PATCH] xlog: added request details to panic message for broken LSN
2018-08-09 15:02 [tarantool-patches] [PATCH] xlog: added request details to panic message for broken LSN Sergei Kalashnikov
@ 2018-08-14 16:17 ` Vladimir Davydov
0 siblings, 0 replies; 2+ messages in thread
From: Vladimir Davydov @ 2018-08-14 16:17 UTC (permalink / raw)
To: Sergei Kalashnikov; +Cc: tarantool-patches
Hello,
The patch below is mangled: tabs have been replaced with spaces.
Please use either `git send-email` or a MUA that doesn't mangle patches.
For more details, please see our guideline:
https://tarantool.io/en/doc/1.9/dev_guide/developer_guidelines/#how-to-submit-a-patch-for-review
On Thu, Aug 09, 2018 at 06:02:13PM +0300, Sergei Kalashnikov wrote:
> Aid the debugging of replication issues related to out-of-order requests.
> Adds the details of request/tuple to the diagnostic message whenever possible.
Commit message text width should be < 72 characters
>
> Fixes: #3105
Should be 'Closes #3105'
Also, the subject line should be in the imperative mood
(xlog: add request details ...)
For more information about how to write a commit message, please see
our guideline:
https://tarantool.io/en/doc/1.9/dev_guide/developer_guidelines/#how-to-write-a-commit-message
> ---
> Ticket:https://github.com/tarantool/tarantool/issues/3105
> Branch:ztarvos/gh-3105-log-request-broken-lsn
"Ticket:" and "Branch:" prefixes are not necessary. It's clear which
is which without them. Also, the branch should given as a hyper link.
In your case it would be:
https://github.com/tarantool/tarantool/commits/ztarvos/gh-3105-log-request-broken-lsn
>
> src/box/applier.cc | 8 +-
> src/box/recovery.cc | 4 +-
> src/box/vclock.c | 6 +
> src/box/vclock.h | 22 +++
> src/box/wal.c | 12 +-
> src/box/xrow.c | 24 +++
> src/box/xrow.h | 15 ++
> test/xlog/log_request_broken_lsn_panic.result | 200 ++++++++++++++++++++++++
> test/xlog/log_request_broken_lsn_panic.test.lua | 105 +++++++++++++
> test/xlog/panic_broken_lsn.lua | 11 ++
> 10 files changed, 395 insertions(+), 12 deletions(-)
> create mode 100644 test/xlog/log_request_broken_lsn_panic.result
> create mode 100644 test/xlog/log_request_broken_lsn_panic.test.lua
> create mode 100644 test/xlog/panic_broken_lsn.lua
The commit adds some trailing space. They aren't visible in the diff
below, because your MUA mangles spaces, but they are visible on the
branch with the commit: see `git show 201114199d`, lines 99, 168, 312,
322, 324, 326, 328, 330, 331, 368. Please look through your patches
before submitting them to make sure it doesn't happen. Adding
[color]
ui = true
to your gitconfig might be helpful.
Regarding the patch itself. After it is applied, vclock_follow() is only
used in mp_decode_vclock(). The latter can't panic on invalid LSN order
so you could use vclock_follow_unsafe() there as well.
That said, you only need two functions:
1. Plain vclock_follow(). This one doesn't need the panic().
A simple assertion will do. No need in '_unsafe' suffix.
2. A function that takes an xrow instead of replica_id/lsn.
Let's call it vclock_follow_xrow(), not vice versa as in your patch,
because 'xrow' is a mere argument here, not a subject/object.
This function should be a wrapper around vclock_follow() which
checks LSN order before calling it. I guess it could be defined
in a header, because it's going to be pretty short.
Also, this function doesn't need to take replica_id/lsn explicitly,
as it can use the corresponding members of the xrow_header struct.
I think we should use this function everywhere where we have an
xrow, even if the order can't be broken due to some extra checks
(this wouldn't make the code any slower than it is now, because
vclock_follow(), which is currently used, always does the check).
Regarding the test. It's too complex IMHO. And the most of the
complexity comes from the code that generates a broken WAL. May be,
we could simplify it by using error injection to generate a broken
WAL instead (see src/errinj.c)?
Also, the test only checks the case of broken LSN order on recovery
while this feature is primarily needed for the case of broken
replication (because on local recovery we can use `tarantoolctl cat`
to find a broken record). Do you think if it's possible to test
vclock_follow_xrow() in the applier code as well?
^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-08-14 16:17 ` Vladimir Davydov
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