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netdata_netdata/database/engine/rrdengineapi.c
Markos Fountoulakis 6b119d9170
Drop dirty dbengine pages if disk cannot keep up () 
* Introduce dirty page pressure handling in the dbengine page cache that invalidates pages when the disk cannot keep up with the flushing speed.
2020-02-06 21:58:13 +02:00

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// SPDX-License-Identifier: GPL-3.0-or-later
#include "rrdengine.h"
/* Default global database instance */
static struct rrdengine_instance default_global_ctx;
int default_rrdeng_page_cache_mb = 32;
int default_rrdeng_disk_quota_mb = RRDENG_MIN_DISK_SPACE_MB;
/* Default behaviour is to unblock data collection if the page cache is full of dirty pages by dropping metrics */
uint8_t rrdeng_drop_metrics_under_page_cache_pressure = 1;
/*
* Gets a handle for storing metrics to the database.
* The handle must be released with rrdeng_store_metric_final().
*/
void rrdeng_store_metric_init(RRDDIM *rd)
{
struct rrdeng_collect_handle *handle;
struct page_cache *pg_cache;
struct rrdengine_instance *ctx;
uuid_t temp_id;
Pvoid_t *PValue;
struct pg_cache_page_index *page_index;
EVP_MD_CTX *evpctx;
unsigned char hash_value[EVP_MAX_MD_SIZE];
unsigned int hash_len;
//&default_global_ctx; TODO: test this use case or remove it?
ctx = rd->rrdset->rrdhost->rrdeng_ctx;
pg_cache = &ctx->pg_cache;
handle = &rd->state->handle.rrdeng;
handle->ctx = ctx;
evpctx = EVP_MD_CTX_create();
EVP_DigestInit_ex(evpctx, EVP_sha256(), NULL);
EVP_DigestUpdate(evpctx, rd->id, strlen(rd->id));
EVP_DigestUpdate(evpctx, rd->rrdset->id, strlen(rd->rrdset->id));
EVP_DigestFinal_ex(evpctx, hash_value, &hash_len);
EVP_MD_CTX_destroy(evpctx);
assert(hash_len > sizeof(temp_id));
memcpy(&temp_id, hash_value, sizeof(temp_id));
handle->descr = NULL;
handle->prev_descr = NULL;
handle->unaligned_page = 0;
uv_rwlock_rdlock(&pg_cache->metrics_index.lock);
PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, &temp_id, sizeof(uuid_t));
if (likely(NULL != PValue)) {
page_index = *PValue;
}
uv_rwlock_rdunlock(&pg_cache->metrics_index.lock);
if (NULL == PValue) {
/* First time we see the UUID */
uv_rwlock_wrlock(&pg_cache->metrics_index.lock);
PValue = JudyHSIns(&pg_cache->metrics_index.JudyHS_array, &temp_id, sizeof(uuid_t), PJE0);
assert(NULL == *PValue); /* TODO: figure out concurrency model */
*PValue = page_index = create_page_index(&temp_id);
page_index->prev = pg_cache->metrics_index.last_page_index;
pg_cache->metrics_index.last_page_index = page_index;
uv_rwlock_wrunlock(&pg_cache->metrics_index.lock);
}
rd->state->rrdeng_uuid = &page_index->id;
handle->page_index = page_index;
}
/* The page must be populated and referenced */
static int page_has_only_empty_metrics(struct rrdeng_page_descr *descr)
{
unsigned i;
uint8_t has_only_empty_metrics = 1;
storage_number *page;
page = descr->pg_cache_descr->page;
for (i = 0 ; i < descr->page_length / sizeof(storage_number); ++i) {
if (SN_EMPTY_SLOT != page[i]) {
has_only_empty_metrics = 0;
break;
}
}
return has_only_empty_metrics;
}
void rrdeng_store_metric_flush_current_page(RRDDIM *rd)
{
struct rrdeng_collect_handle *handle;
struct rrdengine_instance *ctx;
struct rrdeng_page_descr *descr;
handle = &rd->state->handle.rrdeng;
ctx = handle->ctx;
descr = handle->descr;
if (unlikely(NULL == descr)) {
return;
}
if (likely(descr->page_length)) {
int ret, page_is_empty;
rrd_stat_atomic_add(&ctx->stats.metric_API_producers, -1);
if (handle->prev_descr) {
/* unpin old second page */
pg_cache_put(ctx, handle->prev_descr);
}
page_is_empty = page_has_only_empty_metrics(descr);
if (page_is_empty) {
debug(D_RRDENGINE, "Page has empty metrics only, deleting:");
if (unlikely(debug_flags & D_RRDENGINE))
print_page_cache_descr(descr);
pg_cache_put(ctx, descr);
pg_cache_punch_hole(ctx, descr, 1, 0);
handle->prev_descr = NULL;
} else {
/* added 1 extra reference to keep 2 dirty pages pinned per metric, expected refcnt = 2 */
rrdeng_page_descr_mutex_lock(ctx, descr);
ret = pg_cache_try_get_unsafe(descr, 0);
rrdeng_page_descr_mutex_unlock(ctx, descr);
assert (1 == ret);
rrdeng_commit_page(ctx, descr, handle->page_correlation_id);
handle->prev_descr = descr;
}
} else {
freez(descr->pg_cache_descr->page);
rrdeng_destroy_pg_cache_descr(ctx, descr->pg_cache_descr);
freez(descr);
}
handle->descr = NULL;
}
void rrdeng_store_metric_next(RRDDIM *rd, usec_t point_in_time, storage_number number)
{
struct rrdeng_collect_handle *handle;
struct rrdengine_instance *ctx;
struct page_cache *pg_cache;
struct rrdeng_page_descr *descr;
storage_number *page;
uint8_t must_flush_unaligned_page = 0, perfect_page_alignment = 0;
handle = &rd->state->handle.rrdeng;
ctx = handle->ctx;
pg_cache = &ctx->pg_cache;
descr = handle->descr;
if (descr) {
/* Make alignment decisions */
if (descr->page_length == rd->rrdset->rrddim_page_alignment) {
/* this is the leading dimension that defines chart alignment */
perfect_page_alignment = 1;
}
/* is the metric far enough out of alignment with the others? */
if (unlikely(descr->page_length + sizeof(number) < rd->rrdset->rrddim_page_alignment)) {
handle->unaligned_page = 1;
debug(D_RRDENGINE, "Metric page is not aligned with chart:");
if (unlikely(debug_flags & D_RRDENGINE))
print_page_cache_descr(descr);
}
if (unlikely(handle->unaligned_page &&
/* did the other metrics change page? */
rd->rrdset->rrddim_page_alignment <= sizeof(number))) {
debug(D_RRDENGINE, "Flushing unaligned metric page.");
must_flush_unaligned_page = 1;
handle->unaligned_page = 0;
}
}
if (unlikely(NULL == descr ||
descr->page_length + sizeof(number) > RRDENG_BLOCK_SIZE ||
must_flush_unaligned_page)) {
rrdeng_store_metric_flush_current_page(rd);
page = rrdeng_create_page(ctx, &handle->page_index->id, &descr);
assert(page);
handle->descr = descr;
uv_rwlock_wrlock(&pg_cache->committed_page_index.lock);
handle->page_correlation_id = pg_cache->committed_page_index.latest_corr_id++;
uv_rwlock_wrunlock(&pg_cache->committed_page_index.lock);
if (0 == rd->rrdset->rrddim_page_alignment) {
/* this is the leading dimension that defines chart alignment */
perfect_page_alignment = 1;
}
}
page = descr->pg_cache_descr->page;
page[descr->page_length / sizeof(number)] = number;
pg_cache_atomic_set_pg_info(descr, point_in_time, descr->page_length + sizeof(number));
if (perfect_page_alignment)
rd->rrdset->rrddim_page_alignment = descr->page_length;
if (unlikely(INVALID_TIME == descr->start_time)) {
descr->start_time = point_in_time;
rrd_stat_atomic_add(&ctx->stats.metric_API_producers, 1);
pg_cache_insert(ctx, handle->page_index, descr);
} else {
pg_cache_add_new_metric_time(handle->page_index, descr);
}
}
/*
* Releases the database reference from the handle for storing metrics.
*/
void rrdeng_store_metric_finalize(RRDDIM *rd)
{
struct rrdeng_collect_handle *handle;
struct rrdengine_instance *ctx;
handle = &rd->state->handle.rrdeng;
ctx = handle->ctx;
rrdeng_store_metric_flush_current_page(rd);
if (handle->prev_descr) {
/* unpin old second page */
pg_cache_put(ctx, handle->prev_descr);
}
}
/* Returns 1 if the data collection interval is well defined, 0 otherwise */
static int metrics_with_known_interval(struct rrdeng_page_descr *descr)
{
unsigned page_entries;
if (unlikely(INVALID_TIME == descr->start_time || INVALID_TIME == descr->end_time))
return 0;
page_entries = descr->page_length / sizeof(storage_number);
if (likely(page_entries > 1)) {
return 1;
}
return 0;
}
static inline uint32_t *pginfo_to_dt(struct rrdeng_page_info *page_info)
{
return (uint32_t *)&page_info->scratch[0];
}
static inline uint32_t *pginfo_to_points(struct rrdeng_page_info *page_info)
{
return (uint32_t *)&page_info->scratch[sizeof(uint32_t)];
}
/**
* Calculates the regions of different data collection intervals in a netdata chart in the time range
* [start_time,end_time]. This call takes the netdata chart read lock.
* @param st the netdata chart whose data collection interval boundaries are calculated.
* @param start_time inclusive starting time in usec
* @param end_time inclusive ending time in usec
* @param region_info_arrayp It allocates (*region_info_arrayp) and populates it with information of regions of a
* reference dimension that that have different data collection intervals and overlap with the time range
* [start_time,end_time]. The caller must free (*region_info_arrayp) with freez(). If region_info_arrayp is set
* to NULL nothing was allocated.
* @param max_intervalp is derefenced and set to be the largest data collection interval of all regions.
* @return number of regions with different data collection intervals.
*/
unsigned rrdeng_variable_step_boundaries(RRDSET *st, time_t start_time, time_t end_time,
struct rrdeng_region_info **region_info_arrayp, unsigned *max_intervalp)
{
struct pg_cache_page_index *page_index;
struct rrdengine_instance *ctx;
unsigned pages_nr;
RRDDIM *rd_iter, *rd;
struct rrdeng_page_info *page_info_array, *curr, *prev, *old_prev;
unsigned i, j, page_entries, region_points, page_points, regions, max_interval;
time_t now;
usec_t dt, current_position_time, max_time = 0, min_time, curr_time, first_valid_time_in_page;
struct rrdeng_region_info *region_info_array;
uint8_t is_first_region_initialized;
ctx = st->rrdhost->rrdeng_ctx;
regions = 1;
*max_intervalp = max_interval = 0;
region_info_array = NULL;
*region_info_arrayp = NULL;
page_info_array = NULL;
rrdset_rdlock(st);
for(rd_iter = st->dimensions, rd = NULL, min_time = (usec_t)-1 ; rd_iter ; rd_iter = rd_iter->next) {
/*
* Choose oldest dimension as reference. This is not equivalent to the union of all dimensions
* but it is a best effort approximation with a bias towards older metrics in a chart. It
* matches netdata behaviour in the sense that dimensions are generally aligned in a chart
* and older dimensions contain more information about the time range. It does not work well
* for metrics that have recently stopped being collected.
*/
curr_time = pg_cache_oldest_time_in_range(ctx, rd_iter->state->rrdeng_uuid,
start_time * USEC_PER_SEC, end_time * USEC_PER_SEC);
if (INVALID_TIME != curr_time && curr_time < min_time) {
rd = rd_iter;
min_time = curr_time;
}
}
rrdset_unlock(st);
if (NULL == rd) {
return 1;
}
pages_nr = pg_cache_preload(ctx, rd->state->rrdeng_uuid, start_time * USEC_PER_SEC, end_time * USEC_PER_SEC,
&page_info_array, &page_index);
if (pages_nr) {
/* conservative allocation, will reduce the size later if necessary */
region_info_array = mallocz(sizeof(*region_info_array) * pages_nr);
}
is_first_region_initialized = 0;
region_points = 0;
/* pages loop */
for (i = 0, curr = NULL, prev = NULL ; i < pages_nr ; ++i) {
old_prev = prev;
prev = curr;
curr = &page_info_array[i];
*pginfo_to_points(curr) = 0; /* initialize to invalid page */
*pginfo_to_dt(curr) = 0; /* no known data collection interval yet */
if (unlikely(INVALID_TIME == curr->start_time || INVALID_TIME == curr->end_time ||
curr->end_time < curr->start_time)) {
info("Ignoring page with invalid timestamps.");
prev = old_prev;
continue;
}
page_entries = curr->page_length / sizeof(storage_number);
assert(0 != page_entries);
if (likely(1 != page_entries)) {
dt = (curr->end_time - curr->start_time) / (page_entries - 1);
*pginfo_to_dt(curr) = ROUND_USEC_TO_SEC(dt);
if (unlikely(0 == *pginfo_to_dt(curr)))
*pginfo_to_dt(curr) = 1;
} else {
dt = 0;
}
for (j = 0, page_points = 0 ; j < page_entries ; ++j) {
uint8_t is_metric_out_of_order, is_metric_earlier_than_range;
is_metric_earlier_than_range = 0;
is_metric_out_of_order = 0;
current_position_time = curr->start_time + j * dt;
now = current_position_time / USEC_PER_SEC;
if (now > end_time) { /* there will be no more pages in the time range */
break;
}
if (now < start_time)
is_metric_earlier_than_range = 1;
if (unlikely(current_position_time < max_time)) /* just went back in time */
is_metric_out_of_order = 1;
if (is_metric_earlier_than_range || unlikely(is_metric_out_of_order)) {
if (unlikely(is_metric_out_of_order))
info("Ignoring metric with out of order timestamp.");
continue; /* next entry */
}
/* here is a valid metric */
++page_points;
region_info_array[regions - 1].points = ++region_points;
max_time = current_position_time;
if (1 == page_points)
first_valid_time_in_page = current_position_time;
if (unlikely(!is_first_region_initialized)) {
assert(1 == regions);
/* this is the first region */
region_info_array[0].start_time = current_position_time;
is_first_region_initialized = 1;
}
}
*pginfo_to_points(curr) = page_points;
if (0 == page_points) {
prev = old_prev;
continue;
}
if (unlikely(0 == *pginfo_to_dt(curr))) { /* unknown data collection interval */
assert(1 == page_points);
if (likely(NULL != prev)) { /* get interval from previous page */
*pginfo_to_dt(curr) = *pginfo_to_dt(prev);
} else { /* there is no previous page in the query */
struct rrdeng_page_info db_page_info;
/* go to database */
pg_cache_get_filtered_info_prev(ctx, page_index, curr->start_time,
metrics_with_known_interval, &db_page_info);
if (unlikely(db_page_info.start_time == INVALID_TIME || db_page_info.end_time == INVALID_TIME ||
0 == db_page_info.page_length)) { /* nothing in the database, default to update_every */
*pginfo_to_dt(curr) = rd->update_every;
} else {
unsigned db_entries;
usec_t db_dt;
db_entries = db_page_info.page_length / sizeof(storage_number);
db_dt = (db_page_info.end_time - db_page_info.start_time) / (db_entries - 1);
*pginfo_to_dt(curr) = ROUND_USEC_TO_SEC(db_dt);
if (unlikely(0 == *pginfo_to_dt(curr)))
*pginfo_to_dt(curr) = 1;
}
}
}
if (likely(prev) && unlikely(*pginfo_to_dt(curr) != *pginfo_to_dt(prev))) {
info("Data collection interval change detected in query: %"PRIu32" -> %"PRIu32,
*pginfo_to_dt(prev), *pginfo_to_dt(curr));
region_info_array[regions++ - 1].points -= page_points;
region_info_array[regions - 1].points = region_points = page_points;
region_info_array[regions - 1].start_time = first_valid_time_in_page;
}
if (*pginfo_to_dt(curr) > max_interval)
max_interval = *pginfo_to_dt(curr);
region_info_array[regions - 1].update_every = *pginfo_to_dt(curr);
}
if (page_info_array)
freez(page_info_array);
if (region_info_array) {
if (likely(is_first_region_initialized)) {
/* free unnecessary memory */
region_info_array = reallocz(region_info_array, sizeof(*region_info_array) * regions);
*region_info_arrayp = region_info_array;
*max_intervalp = max_interval;
} else {
/* empty result */
freez(region_info_array);
}
}
return regions;
}
/*
* Gets a handle for loading metrics from the database.
* The handle must be released with rrdeng_load_metric_final().
*/
void rrdeng_load_metric_init(RRDDIM *rd, struct rrddim_query_handle *rrdimm_handle, time_t start_time, time_t end_time)
{
struct rrdeng_query_handle *handle;
struct rrdengine_instance *ctx;
unsigned pages_nr;
ctx = rd->rrdset->rrdhost->rrdeng_ctx;
rrdimm_handle->start_time = start_time;
rrdimm_handle->end_time = end_time;
handle = &rrdimm_handle->rrdeng;
handle->next_page_time = start_time;
handle->now = start_time;
handle->position = 0;
handle->ctx = ctx;
handle->descr = NULL;
pages_nr = pg_cache_preload(ctx, rd->state->rrdeng_uuid, start_time * USEC_PER_SEC, end_time * USEC_PER_SEC,
NULL, &handle->page_index);
if (unlikely(NULL == handle->page_index || 0 == pages_nr))
/* there are no metrics to load */
handle->next_page_time = INVALID_TIME;
}
/* Returns the metric and sets its timestamp into current_time */
storage_number rrdeng_load_metric_next(struct rrddim_query_handle *rrdimm_handle, time_t *current_time)
{
struct rrdeng_query_handle *handle;
struct rrdengine_instance *ctx;
struct rrdeng_page_descr *descr;
storage_number *page, ret;
unsigned position, entries;
usec_t next_page_time, current_position_time, page_end_time;
uint32_t page_length;
handle = &rrdimm_handle->rrdeng;
if (unlikely(INVALID_TIME == handle->next_page_time)) {
return SN_EMPTY_SLOT;
}
ctx = handle->ctx;
if (unlikely(NULL == (descr = handle->descr))) {
/* it's the first call */
next_page_time = handle->next_page_time * USEC_PER_SEC;
} else {
pg_cache_atomic_get_pg_info(descr, &page_end_time, &page_length);
}
position = handle->position + 1;
if (unlikely(NULL == descr ||
position >= (page_length / sizeof(storage_number)))) {
/* We need to get a new page */
if (descr) {
/* Drop old page's reference */
#ifdef NETDATA_INTERNAL_CHECKS
rrd_stat_atomic_add(&ctx->stats.metric_API_consumers, -1);
#endif
pg_cache_put(ctx, descr);
handle->descr = NULL;
handle->next_page_time = (page_end_time / USEC_PER_SEC) + 1;
if (unlikely(handle->next_page_time > rrdimm_handle->end_time)) {
goto no_more_metrics;
}
next_page_time = handle->next_page_time * USEC_PER_SEC;
}
descr = pg_cache_lookup_next(ctx, handle->page_index, &handle->page_index->id,
next_page_time, rrdimm_handle->end_time * USEC_PER_SEC);
if (NULL == descr) {
goto no_more_metrics;
}
#ifdef NETDATA_INTERNAL_CHECKS
rrd_stat_atomic_add(&ctx->stats.metric_API_consumers, 1);
#endif
handle->descr = descr;
pg_cache_atomic_get_pg_info(descr, &page_end_time, &page_length);
if (unlikely(INVALID_TIME == descr->start_time ||
INVALID_TIME == page_end_time)) {
goto no_more_metrics;
}
if (unlikely(descr->start_time != page_end_time && next_page_time > descr->start_time)) {
/* we're in the middle of the page somewhere */
entries = page_length / sizeof(storage_number);
position = ((uint64_t)(next_page_time - descr->start_time)) * (entries - 1) /
(page_end_time - descr->start_time);
} else {
position = 0;
}
}
page = descr->pg_cache_descr->page;
ret = page[position];
entries = page_length / sizeof(storage_number);
if (entries > 1) {
usec_t dt;
dt = (page_end_time - descr->start_time) / (entries - 1);
current_position_time = descr->start_time + position * dt;
} else {
current_position_time = descr->start_time;
}
handle->position = position;
handle->now = current_position_time / USEC_PER_SEC;
/* assert(handle->now >= rrdimm_handle->start_time && handle->now <= rrdimm_handle->end_time);
The above assertion is an approximation and needs to take update_every into account */
if (unlikely(handle->now >= rrdimm_handle->end_time)) {
/* next calls will not load any more metrics */
handle->next_page_time = INVALID_TIME;
}
*current_time = handle->now;
return ret;
no_more_metrics:
handle->next_page_time = INVALID_TIME;
return SN_EMPTY_SLOT;
}
int rrdeng_load_metric_is_finished(struct rrddim_query_handle *rrdimm_handle)
{
struct rrdeng_query_handle *handle;
handle = &rrdimm_handle->rrdeng;
return (INVALID_TIME == handle->next_page_time);
}
/*
* Releases the database reference from the handle for loading metrics.
*/
void rrdeng_load_metric_finalize(struct rrddim_query_handle *rrdimm_handle)
{
struct rrdeng_query_handle *handle;
struct rrdengine_instance *ctx;
struct rrdeng_page_descr *descr;
handle = &rrdimm_handle->rrdeng;
ctx = handle->ctx;
descr = handle->descr;
if (descr) {
#ifdef NETDATA_INTERNAL_CHECKS
rrd_stat_atomic_add(&ctx->stats.metric_API_consumers, -1);
#endif
pg_cache_put(ctx, descr);
}
}
time_t rrdeng_metric_latest_time(RRDDIM *rd)
{
struct rrdeng_collect_handle *handle;
struct pg_cache_page_index *page_index;
handle = &rd->state->handle.rrdeng;
page_index = handle->page_index;
return page_index->latest_time / USEC_PER_SEC;
}
time_t rrdeng_metric_oldest_time(RRDDIM *rd)
{
struct rrdeng_collect_handle *handle;
struct pg_cache_page_index *page_index;
handle = &rd->state->handle.rrdeng;
page_index = handle->page_index;
return page_index->oldest_time / USEC_PER_SEC;
}
/* Also gets a reference for the page */
void *rrdeng_create_page(struct rrdengine_instance *ctx, uuid_t *id, struct rrdeng_page_descr **ret_descr)
{
struct rrdeng_page_descr *descr;
struct page_cache_descr *pg_cache_descr;
void *page;
/* TODO: check maximum number of pages in page cache limit */
descr = pg_cache_create_descr();
descr->id = id; /* TODO: add page type: metric, log, something? */
page = mallocz(RRDENG_BLOCK_SIZE); /*TODO: add page size */
rrdeng_page_descr_mutex_lock(ctx, descr);
pg_cache_descr = descr->pg_cache_descr;
pg_cache_descr->page = page;
pg_cache_descr->flags = RRD_PAGE_DIRTY /*| RRD_PAGE_LOCKED */ | RRD_PAGE_POPULATED /* | BEING_COLLECTED */;
pg_cache_descr->refcnt = 1;
debug(D_RRDENGINE, "Created new page:");
if (unlikely(debug_flags & D_RRDENGINE))
print_page_cache_descr(descr);
rrdeng_page_descr_mutex_unlock(ctx, descr);
*ret_descr = descr;
return page;
}
/* The page must not be empty */
void rrdeng_commit_page(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr,
Word_t page_correlation_id)
{
struct page_cache *pg_cache = &ctx->pg_cache;
Pvoid_t *PValue;
unsigned nr_committed_pages;
if (unlikely(NULL == descr)) {
debug(D_RRDENGINE, "%s: page descriptor is NULL, page has already been force-committed.", __func__);
return;
}
assert(descr->page_length);
uv_rwlock_wrlock(&pg_cache->committed_page_index.lock);
PValue = JudyLIns(&pg_cache->committed_page_index.JudyL_array, page_correlation_id, PJE0);
*PValue = descr;
nr_committed_pages = ++pg_cache->committed_page_index.nr_committed_pages;
uv_rwlock_wrunlock(&pg_cache->committed_page_index.lock);
if (nr_committed_pages >= pg_cache_hard_limit(ctx) / 2) {
/* over 50% of pages have not been committed yet */
if (ctx->drop_metrics_under_page_cache_pressure &&
nr_committed_pages >= pg_cache_committed_hard_limit(ctx)) {
/* 100% of pages are dirty */
struct rrdeng_cmd cmd;
cmd.opcode = RRDENG_INVALIDATE_OLDEST_MEMORY_PAGE;
rrdeng_enq_cmd(&ctx->worker_config, &cmd);
} else {
if (0 == (unsigned long) ctx->stats.pg_cache_over_half_dirty_events) {
/* only print the first time */
errno = 0;
error("Failed to flush dirty buffers quickly enough in dbengine instance \"%s\". "
"Metric data at risk of not being stored in the database, "
"please reduce disk load or use a faster disk.", ctx->dbfiles_path);
}
rrd_stat_atomic_add(&ctx->stats.pg_cache_over_half_dirty_events, 1);
rrd_stat_atomic_add(&global_pg_cache_over_half_dirty_events, 1);
}
}
pg_cache_put(ctx, descr);
}
/* Gets a reference for the page */
void *rrdeng_get_latest_page(struct rrdengine_instance *ctx, uuid_t *id, void **handle)
{
struct rrdeng_page_descr *descr;
struct page_cache_descr *pg_cache_descr;
debug(D_RRDENGINE, "Reading existing page:");
descr = pg_cache_lookup(ctx, NULL, id, INVALID_TIME);
if (NULL == descr) {
*handle = NULL;
return NULL;
}
*handle = descr;
pg_cache_descr = descr->pg_cache_descr;
return pg_cache_descr->page;
}
/* Gets a reference for the page */
void *rrdeng_get_page(struct rrdengine_instance *ctx, uuid_t *id, usec_t point_in_time, void **handle)
{
struct rrdeng_page_descr *descr;
struct page_cache_descr *pg_cache_descr;
debug(D_RRDENGINE, "Reading existing page:");
descr = pg_cache_lookup(ctx, NULL, id, point_in_time);
if (NULL == descr) {
*handle = NULL;
return NULL;
}
*handle = descr;
pg_cache_descr = descr->pg_cache_descr;
return pg_cache_descr->page;
}
/*
* Gathers Database Engine statistics.
* Careful when modifying this function.
* You must not change the indices of the statistics or user code will break.
* You must not exceed RRDENG_NR_STATS or it will crash.
*/
void rrdeng_get_37_statistics(struct rrdengine_instance *ctx, unsigned long long *array)
{
struct page_cache *pg_cache = &ctx->pg_cache;
array[0] = (uint64_t)ctx->stats.metric_API_producers;
array[1] = (uint64_t)ctx->stats.metric_API_consumers;
array[2] = (uint64_t)pg_cache->page_descriptors;
array[3] = (uint64_t)pg_cache->populated_pages;
array[4] = (uint64_t)pg_cache->committed_page_index.nr_committed_pages;
array[5] = (uint64_t)ctx->stats.pg_cache_insertions;
array[6] = (uint64_t)ctx->stats.pg_cache_deletions;
array[7] = (uint64_t)ctx->stats.pg_cache_hits;
array[8] = (uint64_t)ctx->stats.pg_cache_misses;
array[9] = (uint64_t)ctx->stats.pg_cache_backfills;
array[10] = (uint64_t)ctx->stats.pg_cache_evictions;
array[11] = (uint64_t)ctx->stats.before_compress_bytes;
array[12] = (uint64_t)ctx->stats.after_compress_bytes;
array[13] = (uint64_t)ctx->stats.before_decompress_bytes;
array[14] = (uint64_t)ctx->stats.after_decompress_bytes;
array[15] = (uint64_t)ctx->stats.io_write_bytes;
array[16] = (uint64_t)ctx->stats.io_write_requests;
array[17] = (uint64_t)ctx->stats.io_read_bytes;
array[18] = (uint64_t)ctx->stats.io_read_requests;
array[19] = (uint64_t)ctx->stats.io_write_extent_bytes;
array[20] = (uint64_t)ctx->stats.io_write_extents;
array[21] = (uint64_t)ctx->stats.io_read_extent_bytes;
array[22] = (uint64_t)ctx->stats.io_read_extents;
array[23] = (uint64_t)ctx->stats.datafile_creations;
array[24] = (uint64_t)ctx->stats.datafile_deletions;
array[25] = (uint64_t)ctx->stats.journalfile_creations;
array[26] = (uint64_t)ctx->stats.journalfile_deletions;
array[27] = (uint64_t)ctx->stats.page_cache_descriptors;
array[28] = (uint64_t)ctx->stats.io_errors;
array[29] = (uint64_t)ctx->stats.fs_errors;
array[30] = (uint64_t)global_io_errors;
array[31] = (uint64_t)global_fs_errors;
array[32] = (uint64_t)rrdeng_reserved_file_descriptors;
array[33] = (uint64_t)ctx->stats.pg_cache_over_half_dirty_events;
array[34] = (uint64_t)global_pg_cache_over_half_dirty_events;
array[35] = (uint64_t)ctx->stats.flushing_pressure_page_deletions;
array[36] = (uint64_t)global_flushing_pressure_page_deletions;
assert(RRDENG_NR_STATS == 37);
}
/* Releases reference to page */
void rrdeng_put_page(struct rrdengine_instance *ctx, void *handle)
{
(void)ctx;
pg_cache_put(ctx, (struct rrdeng_page_descr *)handle);
}
/*
* Returns 0 on success, negative on error
*/
int rrdeng_init(struct rrdengine_instance **ctxp, char *dbfiles_path, unsigned page_cache_mb, unsigned disk_space_mb)
{
struct rrdengine_instance *ctx;
int error;
uint32_t max_open_files;
max_open_files = rlimit_nofile.rlim_cur / 4;
/* reserve RRDENG_FD_BUDGET_PER_INSTANCE file descriptors for this instance */
rrd_stat_atomic_add(&rrdeng_reserved_file_descriptors, RRDENG_FD_BUDGET_PER_INSTANCE);
if (rrdeng_reserved_file_descriptors > max_open_files) {
error("Exceeded the budget of available file descriptors (%u/%u), cannot create new dbengine instance.",
(unsigned)rrdeng_reserved_file_descriptors, (unsigned)max_open_files);
rrd_stat_atomic_add(&global_fs_errors, 1);
rrd_stat_atomic_add(&rrdeng_reserved_file_descriptors, -RRDENG_FD_BUDGET_PER_INSTANCE);
return UV_EMFILE;
}
if (NULL == ctxp) {
/* for testing */
ctx = &default_global_ctx;
memset(ctx, 0, sizeof(*ctx));
} else {
*ctxp = ctx = callocz(1, sizeof(*ctx));
}
ctx->global_compress_alg = RRD_LZ4;
if (page_cache_mb < RRDENG_MIN_PAGE_CACHE_SIZE_MB)
page_cache_mb = RRDENG_MIN_PAGE_CACHE_SIZE_MB;
ctx->max_cache_pages = page_cache_mb * (1048576LU / RRDENG_BLOCK_SIZE);
/* try to keep 5% of the page cache free */
ctx->cache_pages_low_watermark = (ctx->max_cache_pages * 95LLU) / 100;
if (disk_space_mb < RRDENG_MIN_DISK_SPACE_MB)
disk_space_mb = RRDENG_MIN_DISK_SPACE_MB;
ctx->max_disk_space = disk_space_mb * 1048576LLU;
strncpyz(ctx->dbfiles_path, dbfiles_path, sizeof(ctx->dbfiles_path) - 1);
ctx->dbfiles_path[sizeof(ctx->dbfiles_path) - 1] = '\0';
ctx->drop_metrics_under_page_cache_pressure = rrdeng_drop_metrics_under_page_cache_pressure;
memset(&ctx->worker_config, 0, sizeof(ctx->worker_config));
ctx->worker_config.ctx = ctx;
init_page_cache(ctx);
init_commit_log(ctx);
error = init_rrd_files(ctx);
if (error) {
goto error_after_init_rrd_files;
}
init_completion(&ctx->rrdengine_completion);
assert(0 == uv_thread_create(&ctx->worker_config.thread, rrdeng_worker, &ctx->worker_config));
/* wait for worker thread to initialize */
wait_for_completion(&ctx->rrdengine_completion);
destroy_completion(&ctx->rrdengine_completion);
uv_thread_set_name_np(ctx->worker_config.thread, "DBENGINE");
if (ctx->worker_config.error) {
goto error_after_rrdeng_worker;
}
return 0;
error_after_rrdeng_worker:
finalize_rrd_files(ctx);
error_after_init_rrd_files:
free_page_cache(ctx);
if (ctx != &default_global_ctx) {
freez(ctx);
*ctxp = NULL;
}
rrd_stat_atomic_add(&rrdeng_reserved_file_descriptors, -RRDENG_FD_BUDGET_PER_INSTANCE);
return UV_EIO;
}
/*
* Returns 0 on success, 1 on error
*/
int rrdeng_exit(struct rrdengine_instance *ctx)
{
struct rrdeng_cmd cmd;
if (NULL == ctx) {
return 1;
}
/* TODO: add page to page cache */
cmd.opcode = RRDENG_SHUTDOWN;
rrdeng_enq_cmd(&ctx->worker_config, &cmd);
assert(0 == uv_thread_join(&ctx->worker_config.thread));
finalize_rrd_files(ctx);
free_page_cache(ctx);
if (ctx != &default_global_ctx) {
freez(ctx);
}
rrd_stat_atomic_add(&rrdeng_reserved_file_descriptors, -RRDENG_FD_BUDGET_PER_INSTANCE);
return 0;
}
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