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mdbx-tools: rework mdbx_reader_list() & mdbx_stat.

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Change-Id: I0524cad93ca439e74eba9486cbcbeacf4253dd84
This commit is contained in:
Leonid Yuriev
2019-09-19 00:54:03 +03:00
parent 2f2df1ee76
commit 7c39c16829
3 changed files with 119 additions and 49 deletions
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40
mdbx.h
View File

@@ -2716,31 +2716,49 @@ LIBMDBX_API int mdbx_cmp(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *a,
LIBMDBX_API int mdbx_dcmp(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *a,
const MDBX_val *b);
/* A callback function used to print a message from the library.
/* A callback function used to enumerate the reader lock table.
*
* [in] msg The string to be printed.
* [in] ctx An arbitrary context pointer for the callback.
* [in] num The serial number during enumeration, starting from 1.
* [in] slot The reader lock table slot number.
* [in] txnid The ID of the transaction being read,
* i.e. the MVCC-snaphot number.
* [in] lag The lag from a recent MVCC-snapshot, i.e. the number of
* committed transaction since read transaction started.
* [in] pid The reader process ID.
* [in] thread The reader thread ID.
* [in] bytes_used The number of last used page in the MVCC-snapshot which
* being read, i.e. database file can't shrinked beyond this.
* [in] bytes_retired The total size of the database pages that were retired by
* committed write transactions after the reader's
* MVCC-snapshot, i.e. the space which would be freed after
* the Reader releases the MVCC-snapshot for reuse by
* completion read transaction.
*
* Returns < 0 on failure, >= 0 on success. */
typedef int(MDBX_msg_func)(const char *msg, void *ctx);
typedef int(MDBX_reader_list_func)(void *ctx, int num, int slot, mdbx_pid_t pid,
mdbx_tid_t thread, uint64_t txnid,
uint64_t lag, size_t bytes_used,
size_t bytes_retired);
/* FIXME: Rework this function.
*
* Dump the entries in the reader lock table.
/* Enumarete the entries in the reader lock table.
*
* [in] env An environment handle returned by mdbx_env_create()
* [in] func A MDBX_msg_func function
* [in] ctx Anything the message function needs
* [in] func A MDBX_reader_list_func function
* [in] ctx An arbitrary context pointer for the enumeration function.
*
* Returns < 0 on failure, >= 0 on success. */
LIBMDBX_API int mdbx_reader_list(MDBX_env *env, MDBX_msg_func *func, void *ctx);
* Returns A non-zero error value on failure and 0 on success,
* or MDBX_RESULT_TRUE (-1) if the reader lock table is empty. */
LIBMDBX_API int mdbx_reader_list(MDBX_env *env, MDBX_reader_list_func *func,
void *ctx);
/* Check for stale entries in the reader lock table.
*
* [in] env An environment handle returned by mdbx_env_create()
* [out] dead Number of stale slots that were cleared
*
* Returns 0 on success, non-zero on failure. */
* Returns A non-zero error value on failure and 0 on success,
* or MDBX_RESULT_TRUE (-1) if a dead reader(s) found or mutex was recovered. */
LIBMDBX_API int mdbx_reader_check(MDBX_env *env, int *dead);
/* Returns a lag of the reading for the given transaction.

78
src/elements/core.c
View File

@@ -13195,46 +13195,66 @@ int mdbx_set_dupsort(MDBX_txn *txn, MDBX_dbi dbi, MDBX_cmp_func *cmp) {
return MDBX_SUCCESS;
}
int __cold mdbx_reader_list(MDBX_env *env, MDBX_msg_func *func, void *ctx) {
char buf[64];
int rc = 0, first = 1;
int __cold mdbx_reader_list(MDBX_env *env, MDBX_reader_list_func *func,
void *ctx) {
if (unlikely(!env || !func))
return (MDBX_EINVAL > 0) ? -MDBX_EINVAL : MDBX_EINVAL;
return MDBX_EINVAL;
if (unlikely(env->me_signature != MDBX_ME_SIGNATURE))
return MDBX_EBADSIGN;
const MDBX_lockinfo *const lck = env->me_lck;
if (likely(lck)) {
const unsigned snap_nreaders = lck->mti_numreaders;
int rc = MDBX_RESULT_TRUE;
int serial = 0;
if (likely(env->me_lck)) {
const unsigned snap_nreaders = env->me_lck->mti_numreaders;
for (unsigned i = 0; i < snap_nreaders; i++) {
if (lck->mti_readers[i].mr_pid) {
const txnid_t txnid = lck->mti_readers[i].mr_txnid;
if (txnid == ~(txnid_t)0)
snprintf(buf, sizeof(buf), "%10" PRIuPTR " %" PRIxPTR " -\n",
(uintptr_t)lck->mti_readers[i].mr_pid,
(uintptr_t)lck->mti_readers[i].mr_tid);
else
snprintf(buf, sizeof(buf),
"%10" PRIuPTR " %" PRIxPTR " %" PRIaTXN "\n",
(uintptr_t)lck->mti_readers[i].mr_pid,
(uintptr_t)lck->mti_readers[i].mr_tid, txnid);
const MDBX_reader *r = env->me_lck->mti_readers + i;
retry_reader:;
const mdbx_pid_t pid = r->mr_pid;
if (!pid)
continue;
txnid_t txnid = r->mr_txnid;
const mdbx_tid_t tid = r->mr_tid;
const pgno_t pages_used = r->mr_snapshot_pages_used;
const uint64_t reader_pages_retired = r->mr_snapshot_pages_retired;
mdbx_compiler_barrier();
if (unlikely(pid != r->mr_pid || txnid != r->mr_txnid ||
tid != r->mr_tid ||
pages_used != r->mr_snapshot_pages_used ||
reader_pages_retired != r->mr_snapshot_pages_retired))
goto retry_reader;
if (first) {
first = 0;
rc = func(" pid thread txnid\n", ctx);
if (rc < 0)
break;
mdbx_assert(env, txnid > 0);
if (txnid == ~(txnid_t)0)
txnid = 0;
size_t bytes_used = 0;
size_t bytes_retained = 0;
uint64_t lag = 0;
if (txnid) {
retry_header:;
const MDBX_meta *const recent_meta = mdbx_meta_head(env);
const uint64_t head_pages_retired = recent_meta->mm_pages_retired;
const txnid_t head_txnid = mdbx_meta_txnid_fluid(env, recent_meta);
mdbx_compiler_barrier();
if (unlikely(recent_meta != mdbx_meta_head(env) ||
head_pages_retired != recent_meta->mm_pages_retired) ||
head_txnid != mdbx_meta_txnid_fluid(env, recent_meta))
goto retry_header;
lag = head_txnid - txnid;
bytes_used = pgno2bytes(env, pages_used);
bytes_retained = (head_pages_retired > reader_pages_retired)
? pgno2bytes(env, (pgno_t)(head_pages_retired -
reader_pages_retired))
: 0;
}
rc = func(buf, ctx);
if (rc < 0)
rc = func(ctx, ++serial, i, pid, tid, txnid, lag, bytes_used,
bytes_retained);
if (unlikely(rc != MDBX_SUCCESS))
break;
}
}
}
if (first)
rc = func("(no active readers)\n", ctx);
return rc;
}

42
src/tools/mdbx_stat.c
View File

@@ -59,6 +59,27 @@ static void usage(char *prog) {
exit(EXIT_FAILURE);
}
static int reader_list_func(void *ctx, int num, int slot, mdbx_pid_t pid,
mdbx_tid_t thread, uint64_t txnid, uint64_t lag,
size_t bytes_used, size_t bytes_retired) {
(void)ctx;
if (num == 1)
printf("Reader Table Status\n"
" #\tslot\t%6s %*s %20s %10s %13s %13s\n",
"pid", (int)sizeof(size_t) * 2, "thread", "txnid", "lag", "used",
"retained");
printf(" %3d)\t[%d]\t%6" PRIdSIZE " %*" PRIxSIZE, num, slot, (size_t)pid,
(int)sizeof(size_t) * 2, (size_t)thread);
if (txnid)
printf(" %20" PRIu64 " %10" PRIu64 " %12.1fM %12.1fM\n", txnid, lag,
bytes_used / 1048576.0, bytes_retired / 1048576.0);
else
printf(" %20s %10s %13s %13s\n", "-", "0", "0", "0");
return user_break ? MDBX_RESULT_TRUE : MDBX_RESULT_FALSE;
}
int main(int argc, char *argv[]) {
int o, rc;
MDBX_env *env;
@@ -206,13 +227,24 @@ int main(int argc, char *argv[]) {
}
if (rdrinfo) {
printf("Reader Table Status\n");
rc = mdbx_reader_list(env, (MDBX_msg_func *)fputs, stdout);
if (rdrinfo > 1) {
rc = mdbx_reader_list(env, reader_list_func, nullptr);
if (rc == MDBX_RESULT_TRUE)
printf("Reader Table is empty\n");
else if (rc == MDBX_SUCCESS && rdrinfo > 1) {
int dead;
mdbx_reader_check(env, &dead);
rc = mdbx_reader_check(env, &dead);
if (rc == MDBX_RESULT_TRUE) {
printf(" %d stale readers cleared.\n", dead);
rc = mdbx_reader_list(env, (MDBX_msg_func *)fputs, stdout);
rc = mdbx_reader_list(env, reader_list_func, nullptr);
if (rc == MDBX_RESULT_TRUE)
printf(" Now Reader Table is empty\n");
} else
printf(" No stale readers.\n");
}
if (MDBX_IS_ERROR(rc)) {
fprintf(stderr, "mdbx_txn_begin failed, error %d %s\n", rc,
mdbx_strerror(rc));
goto env_close;
}
if (!(subname || alldbs || freinfo))
goto env_close;