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Bug#32169848 THD_NDB TRANSACTION FUNCTIONALITY [#13]
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Describing what update_stats() does and add comments both to
function and callers.
Rewrite get_dynamic_partition_info() and add comments that explains what
it does. There seem to be a side-effect of this function which polutes
various places with stats for only one partition, several notes added.

Change-Id: Ia6bfd06ac586bbad0d3b3c5854ff8620e74f215a
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@blaudden
blaudden committed May 19, 2021
1 parent f7a906b commit 300041c
Showing 1 changed file with 78 additions and 35 deletions.
113 changes: 78 additions & 35 deletions storage/ndb/plugin/ha_ndbcluster.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1227,12 +1227,14 @@ int ha_ndbcluster::records(ha_rows *num_rows) {
("id=%d, no_uncommitted_rows_count=%d", m_table->getTableId(),
m_table_info->no_uncommitted_rows_count));

int error = update_stats(table->in_use, 1);
// Read fresh stats from NDB (one roundtrip)
const int error = update_stats(table->in_use, true);
if (error != 0) {
*num_rows = HA_POS_ERROR;
return error;
}

// Return the "records" from handler::stats::records
*num_rows = stats.records;
return 0;
}
Expand Down Expand Up @@ -6680,7 +6682,6 @@ int ha_ndbcluster::cmp_ref(const uchar *ref1, const uchar *ref2) const {

int ha_ndbcluster::info(uint flag) {
THD *thd = table->in_use;
int result = 0;
DBUG_TRACE;
DBUG_PRINT("enter", ("flag: %d", flag));

Expand Down Expand Up @@ -6721,11 +6722,11 @@ int ha_ndbcluster::info(uint flag) {
m_table_info == NULL || // 3)
m_table_info->records == ~(ha_rows)0) // 3)
{
result = update_stats(thd, (exact_count || !(flag & HA_STATUS_NO_LOCK)));
const int result =
update_stats(thd, (exact_count || !(flag & HA_STATUS_NO_LOCK)));
if (result) return result;
}
/* Read from local statistics, fast and fuzzy, wo/ locks */
else {
} else {
/* Read from local statistics, fast and fuzzy, wo/ locks */
assert(m_table_info->records != ~(ha_rows)0);
stats.records =
m_table_info->records + m_table_info->no_uncommitted_rows_count;
Expand Down Expand Up @@ -6766,43 +6767,60 @@ int ha_ndbcluster::info(uint flag) {
}
}

if (result == -1) result = HA_ERR_NO_CONNECTION;

return result;
return 0;
}

/**
@brief Return statistics for given partition

@param[out] stat_info The place where to return updated statistics
@param[out] checksum The place where to return checksum (if any)
@param part_id Id of the partition to return statistics for
*/
void ha_ndbcluster::get_dynamic_partition_info(ha_statistics *stat_info,
ha_checksum *checksum,
uint part_id) {
DBUG_PRINT("info", ("ha_ndbcluster::get_dynamic_partition_info"));
DBUG_TRACE;
DBUG_PRINT("enter", ("part_id: %d", part_id));

int error = 0;
THD *thd = table->in_use;
if (!thd) thd = current_thd;

/* Checksum not supported, set it to NULL.*/
// Checksum not supported, set it to 0
*checksum = 0;

if (!thd) thd = current_thd;
if (!m_table_info) {
if ((error = check_ndb_connection(thd))) goto err;
// Basically this means that handler is not part of a transaction and thus
// this might be the first time this THD is coming into contact with NDB ->
// need to check the connection.
// NOTE! Further down in this function it calls update_stat() which
// uses m_table (the open NDB table!) when fetching the stats so there is
// basically no way that it's necessary to check NDB connection here.
if (check_ndb_connection(thd) != 0) {
// Nothing to do, caller has initialized stat_info to zero
DBUG_PRINT("error", ("No NDB connection"));
return;
}
}
error = update_stats(thd, 1, part_id);

if (error == 0) {
stat_info->records = stats.records;
stat_info->mean_rec_length = stats.mean_rec_length;
stat_info->data_file_length = stats.data_file_length;
stat_info->delete_length = stats.delete_length;
stat_info->max_data_file_length = stats.max_data_file_length;
// Read fresh stats from NDB for given partition (one roundtrip)
// NOTE! overwrites handler::stats, the NDB_SHARE::cached_table_stats and
// ha_ndbcluster::Ndb_local_table_statistics with values for only given
// partition!
const int error = update_stats(thd, true, part_id);
if (error) {
// Nothing to do, caller has initialized stat_info to zero
DBUG_PRINT("error", ("Failed to update stats"));
return;
}

err:

DBUG_PRINT(
"warning",
("ha_ndbcluster::get_dynamic_partition_info failed with error code %u",
error));
// Return values from handler::stats, the caller will then subsequently update
// handler::stats with these values!
stat_info->records = stats.records;
stat_info->mean_rec_length = stats.mean_rec_length;
stat_info->data_file_length = stats.data_file_length;
stat_info->delete_length = stats.delete_length;
stat_info->max_data_file_length = stats.max_data_file_length;
}

int ha_ndbcluster::extra(enum ha_extra_function operation) {
Expand Down Expand Up @@ -11315,7 +11333,8 @@ int ha_ndbcluster::open(const char *path MY_ATTRIBUTE((unused)),
return res;
}

if ((res = update_stats(thd, 1)) || (res = info(HA_STATUS_CONST))) {
// Read fresh stats from NDB (one roundtrip) and update "constant variables"
if ((res = update_stats(thd, true)) || (res = info(HA_STATUS_CONST))) {
release_key_fields();
release_ndb_share();
NdbDictionary::Dictionary *const dict = thd_ndb->ndb->getDictionary();
Expand Down Expand Up @@ -11425,11 +11444,13 @@ NDB_SHARE *ha_ndbcluster::open_share_before_schema_sync(
* and updates index statistics
*/
int ha_ndbcluster::optimize(THD *thd, HA_CHECK_OPT *) {
ulong error, stats_error = 0;
const uint delay = (uint)THDVAR(thd, optimization_delay);

error = ndb_optimize_table(thd, delay);
stats_error = update_stats(thd, 1);
const int error = ndb_optimize_table(thd, delay);

// Read fresh stats from NDB (one roundtrip)
const int stats_error = update_stats(thd, true);

return (error) ? error : stats_error;
}

Expand Down Expand Up @@ -11502,8 +11523,8 @@ int ha_ndbcluster::ndb_optimize_table(THD *thd, uint delay) const {
int ha_ndbcluster::analyze(THD *thd, HA_CHECK_OPT *) {
DBUG_TRACE;

// update table partition statistics
int error = update_stats(thd, 1);
// Read fresh stats from NDB (one roundtrip)
int error = update_stats(thd, true);

// analyze index if index stat is enabled
if (error == 0 && THDVAR(NULL, index_stat_enable) &&
Expand Down Expand Up @@ -12704,7 +12725,7 @@ ha_rows ha_ndbcluster::records_in_range(uint inx, key_range *min_key,
*/
do {
if (stats.records == ~(ha_rows)0 || stats.records == 0) {
/* Refresh statistics, only read from datanodes if 'use_exact_count' */
// Read fresh stats from NDB (one roundtrip) only if 'use_exact_count'
THD *thd = current_thd;
if (update_stats(thd, THDVAR(thd, use_exact_count))) break;
}
Expand Down Expand Up @@ -12833,6 +12854,26 @@ bool ha_ndbcluster::low_byte_first() const {
#endif
}

/**
@brief Update statistics for the open table.

The function will either use cached table stats from NDB_SHARE or read fresh
table stats from NDB and update the cache, this is controlled by the
do_read_stat argument.

Those table stats will then be used to update the
Ndb_local_table_statistics::records value as well as values in
handler::stats.

@note When using the "part_id" parameter all the three different types of
stats updated by this function will be overwritten with stats pertaining to
only that fragment!

@param thd The THD pointer
@param do_read_stat Read fresh stats from NDB and update cache.
@param part_id The partition id to fetch stats for.
@return 0 on success
*/
int ha_ndbcluster::update_stats(THD *thd, bool do_read_stat, uint part_id) {
NDB_SHARE::Table_stats table_stats;
Thd_ndb *thd_ndb = get_thd_ndb(thd);
Expand All @@ -12853,7 +12894,7 @@ int ha_ndbcluster::update_stats(THD *thd, bool do_read_stat, uint part_id) {
return err;
}

// Update cached stats with fresh data
// Update cached stats in NDB_SHARE with fresh data
if (m_share) {
mysql_mutex_lock(&m_share->mutex);
m_share->cached_table_stats = table_stats;
Expand All @@ -12864,9 +12905,11 @@ int ha_ndbcluster::update_stats(THD *thd, bool do_read_stat, uint part_id) {

int no_uncommitted_rows_count = 0;
if (m_table_info && !thd_ndb->m_error) {
// Update "records" in table info
m_table_info->records = table_stats.row_count;
no_uncommitted_rows_count = m_table_info->no_uncommitted_rows_count;
}
// Update values in handler::stats (another "records")
stats.mean_rec_length = table_stats.row_size;
stats.data_file_length = table_stats.fragment_memory;
stats.records = table_stats.row_count + no_uncommitted_rows_count;
Expand Down

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