def getCostImpl(self, design, num_nodes=None):
"""
Estimate the Disk Cost for a design and a workload
Note: If this is being invoked with overallCost(), then the diskCost()
should be calculated before skewCost() because we will reused the same
histogram of how often nodes are touched in the workload
"""
# delta = self.__getDelta__(design)
# Initialize all of the LRU buffers
# since every lru has the same configuration, we can cache the first initialization then deepcopy it to other
# lrus
cache = None
# for lru in self.buffers:
# cache = lru.initialize(design, delta, cache)
# LOG.info(lru)
# lru.validate()
# Ok strap on your helmet, this is the magical part of the whole thing!
self.buildEmbeddingCostDictionary(design)
# print "Magic map: ", pformat(cost_map)
# print "Magic list: ", child_collections
# Outline:
# + For each operation, we need to figure out what document(s) it's going
# to need to touch. From this we want to compute a unique hash signature
# for those document so that we can identify what node those documents
# reside on and whether those documents are in our working set memory.
#
# + For each node, we are going to have a single LRU buffer that simulates
# the working set for all collections and indexes in the database.
# Documents entries are going to be tagged based on whether they are
# part of an index or a collection.
#
# + Now when we iterate through each operation in our workload, we are
# going to need to first figure out what index (if any) it will need
# to use and how it will be used (i.e., equality look-up or range scan).
# We can then compute the hash for the look-up keys.
# If that key is in the LRU buffer, then we will update its entry's last
# accessed timestamp. If it's not, then we will increase the page hit
# counter and evict some other entry.
# After evaluating the target index, we will check whether the index
# covers the query. If it does, then we're done
# If not, then we need to compute hash for the "base" documents that it
# wants to access (i.e., in the collection). Then just as before, we
# will check whether its in our buffer, make an eviction if not, and
# update our page hit counter.
# There are several additional corner cases that we need to handle:
# INSERT/UPDATE: Check whether it's an upsert query
# INSERT/UPDATE/DELETE: We assume that they're using a WAL and therefore
# writing dirty pages is "free"
# UPDATE/DELETE: Check whether the "multi" flag is set to true, which will
# tell us to stop the scan after the first matching document
# is found.
#
# NOTE: We don't need to keep track of evicted tuples. It's either in the LRU buffer or not.
# TODO: We may want to figure out how to estimate whether we are traversing
# indexes on the right-hand side of the tree. We could some preserve
# the sort order the keys when we hash them...
# Worst case is when every query requires a full collection scan
# Best case, every query is satisfied by main memory
totalWorst = 0
totalCost = 0
sess_ctr = 0
total_index_penalty = 0
total_worst_index_penalty = 0
for sess in self.state.workload:
for op in sess["operations"]:
# is the collection in the design - if not ignore
if not design.hasCollection(op["collection"]):
if self.debug:
LOG.debug("NOT in design: SKIP - All operations on %s", col_name)
continue
if design.isRelaxed(op["collection"]):
if self.debug:
LOG.debug("NOT in design: SKIP - All operations on %s", col_name)
continue
col_info = self.state.collections[op["collection"]]
# Initialize cache if necessary
# We will always want to do this regardless of whether caching is enabled
cache = self.state.getCacheHandle(col_info)
# Check whether we have a cache index selection based on query_hashes
indexKeys, covering, index_size, slot_size = cache.best_index.get(
op["query_hash"], (None, None, None, None)
)
if indexKeys is None:
indexKeys, covering, index_size, slot_size = self.guess_op_info(design, op)
if self.state.cache_enable:
if self.debug:
self.state.cache_miss_ctr.put("best_index")
cache.best_index[op["query_hash"]] = (indexKeys, covering, index_size, slot_size)
elif self.debug:
self.state.cache_hit_ctr.put("best_index")
pageHits = 0
maxHits = 0
indexKeyInsertionPenalty = 0
worst_index_penalty = 0
isRegex = self.state.__getIsOpRegex__(cache, op)
try:
opNodes = self.state.__getNodeIds__(cache, design, op)
except:
if self.debug:
LOG.warn("Failed to estimate touched nodes for op\n%s" % pformat(op))
self.err_ctr += 1
continue
for content in workload.getOpContents(op):
for node_id in opNodes:
lru = self.buffers[node_id]
self.total_op_contents += 1
maxHits += cache.fullscan_pages
indexKeyInsertionPenalty += self.getIndexKeyInsertionPenalty(indexKeys, content)
worst_index_penalty += 1
# If slot size is too large, we consider it as a full page scan
if slot_size >= constants.SLOT_SIZE_LIMIT:
pageHits += cache.fullscan_pages
continue
## FOR
# TODO: Need to handle whether it's a scan or an equality predicate
# TODO: We need to handle when we have a regex predicate. These are tricky
# because they may use an index that will examine all a subset of collections
# and then execute a regex on just those documents.
# If we have a target index, hit that up
if indexKeys and not isRegex: # FIXME
documentId = cache.index_docIds.get(op["query_id"], None)
if documentId is None:
values = catalog.getFieldValues(indexKeys, content)
try:
documentId = hash(values)
except:
if self.debug:
LOG.error(
"Failed to compute index documentIds for op #%d - %s\n%s",
op["query_id"],
values,
pformat(op),
)
self.err_ctr += 1
break
if self.state.cache_enable:
if self.debug:
self.state.cache_miss_ctr.put("index_docIds")
cache.index_docIds[op["query_id"]] = documentId
elif self.debug:
self.state.cache_hit_ctr.put("index_docIds")
## IF
hits = lru.getDocumentFromIndex(indexKeys, index_size)
# print "hits: ", hits
pageHits += hits
# maxHits += hits if op['type'] == constants.OP_TYPE_INSERT else cache.fullscan_pages
if self.debug:
LOG.debug(
"Node #%02d: Estimated %d index scan pageHits for op #%d on %s.%s",
node_id,
hits,
op["query_id"],
op["collection"],
indexKeys,
)
# If we don't have an index, then we know that it's a full scan because the
# collections are unordered
if not indexKeys:
if self.debug:
LOG.debug(
"No index available for op #%d. Will have to do full scan on '%s'",
op["query_id"],
op["collection"],
)
pageHits += cache.fullscan_pages
# maxHits += cache.fullscan_pages
# Otherwise, if it's not a covering index, then we need to hit up
# the collection to retrieve the whole document
elif not covering:
documentId = cache.collection_docIds.get(op["query_id"], None)
if documentId is None:
values = catalog.getAllValues(content)
try:
documentId = hash(values)
except:
if self.debug:
LOG.error(
"Failed to compute collection documentIds for op #%d - %s\n%s",
op["query_id"],
values,
pformat(op),
)
self.err_ctr += 1
break
if self.state.cache_enable:
if self.debug:
self.state.cache_miss_ctr.put("collection_docIds")
cache.collection_docIds[op["query_id"]] = documentId
elif self.debug:
self.state.cache_hit_ctr.put("collection_docIds")
## IF
hits = lru.getDocumentFromCollection(op["collection"], documentId, slot_size)
pageHits += hits
# maxHits += hits if op['type'] == constants.OP_TYPE_INSERT else cache.fullscan_pages
if self.debug:
LOG.debug(
"Node #%02d: Estimated %d collection scan pageHits for op #%d on %s",
node_id,
hits,
op["query_id"],
op["collection"],
)
# We have a covering index, which means that we don't have
# to do a look-up on the document in the collection.
# But we still need to increase maxHits so that the final
# ratio is counted correctly
# Yang seems happy with this...
else:
assert op["type"] != constants.OP_TYPE_INSERT
# maxHits += cache.fullscan_pages
## FOR (node)
## FOR (content)
totalCost += pageHits
totalWorst += maxHits
total_index_penalty += indexKeyInsertionPenalty
total_worst_index_penalty += worst_index_penalty
if self.debug:
LOG.debug(
"Op #%d on '%s' -> [pageHits:%d / worst:%d]",
op["query_id"],
op["collection"],
pageHits,
maxHits,
)
assert pageHits <= maxHits, "Estimated pageHits [%d] is greater than worst [%d] for op #%d\n%s" % (
pageHits,
maxHits,
op["query_id"],
pformat(op),
)
## FOR (op)
sess_ctr += 1
## FOR (sess)
self.total_index_insertion_penalty = total_index_penalty
# Add index insertion penalty to the total cost
if not self.no_index_insertion_penalty:
totalCost += total_index_penalty
totalWorst += total_worst_index_penalty
## IF
# The final disk cost is the ratio of our estimated disk access cost divided
# by the worst possible cost for this design. If we don't have a worst case,
# then the cost is simply zero
if self.debug:
LOG.info("Total operation contents %s, errors %s", self.total_op_contents, self.err_ctr)
assert totalCost <= totalWorst, "Estimated total pageHits [%d] is greater than worst case pageHits [%d]" % (
totalCost,
totalWorst,
)
final_cost = float(totalCost) / float(totalWorst) if totalWorst else 0
evicted = sum([lru.evicted for lru in self.buffers])
LOG.info(
"Computed Disk Cost: %s [pageHits=%d / worstCase=%d / evicted=%d]",
final_cost,
totalCost,
totalWorst,
evicted,
)
return final_cost
def getCostImpl(self, design):
"""
Estimate the Disk Cost for a design and a workload
Note: If this is being invoked with overallCost(), then the diskCost()
should be calculated before skewCost() because we will reused the same
histogram of how often nodes are touched in the workload
"""
# delta = self.__getDelta__(design)
# Initialize all of the LRU buffers
# since every lru has the same configuration, we can cache the first initialization then deepcopy it to other
# lrus
cache = None
# for lru in self.buffers:
# cache = lru.initialize(design, delta, cache)
# LOG.info(lru)
# lru.validate()
# Ok strap on your helmet, this is the magical part of the whole thing!
self.buildEmbeddingCostDictionary(design)
#print "Magic map: ", pformat(cost_map)
#print "Magic list: ", child_collections
# Outline:
# + For each operation, we need to figure out what document(s) it's going
# to need to touch. From this we want to compute a unique hash signature
# for those document so that we can identify what node those documents
# reside on and whether those documents are in our working set memory.
#
# + For each node, we are going to have a single LRU buffer that simulates
# the working set for all collections and indexes in the database.
# Documents entries are going to be tagged based on whether they are
# part of an index or a collection.
#
# + Now when we iterate through each operation in our workload, we are
# going to need to first figure out what index (if any) it will need
# to use and how it will be used (i.e., equality look-up or range scan).
# We can then compute the hash for the look-up keys.
# If that key is in the LRU buffer, then we will update its entry's last
# accessed timestamp. If it's not, then we will increase the page hit
# counter and evict some other entry.
# After evaluating the target index, we will check whether the index
# covers the query. If it does, then we're done
# If not, then we need to compute hash for the "base" documents that it
# wants to access (i.e., in the collection). Then just as before, we
# will check whether its in our buffer, make an eviction if not, and
# update our page hit counter.
# There are several additional corner cases that we need to handle:
# INSERT/UPDATE: Check whether it's an upsert query
# INSERT/UPDATE/DELETE: We assume that they're using a WAL and therefore
# writing dirty pages is "free"
# UPDATE/DELETE: Check whether the "multi" flag is set to true, which will
# tell us to stop the scan after the first matching document
# is found.
#
# NOTE: We don't need to keep track of evicted tuples. It's either in the LRU buffer or not.
# TODO: We may want to figure out how to estimate whether we are traversing
# indexes on the right-hand side of the tree. We could some preserve
# the sort order the keys when we hash them...
# Worst case is when every query requires a full collection scan
# Best case, every query is satisfied by main memory
totalWorst = 0
totalCost = 0
sess_ctr = 0
total_index_penalty = 0
total_worst_index_penalty = 0
for sess in self.state.workload:
for op in sess['operations']:
# is the collection in the design - if not ignore
if not design.hasCollection(op['collection']):
if self.debug: LOG.debug("NOT in design: SKIP - All operations on %s", col_name)
continue
if design.isRelaxed(op['collection']):
if self.debug: LOG.debug("NOT in design: SKIP - All operations on %s", col_name)
continue
col_info = self.state.collections[op['collection']]
# Initialize cache if necessary
# We will always want to do this regardless of whether caching is enabled
cache = self.state.getCacheHandle(col_info)
# Check whether we have a cache index selection based on query_hashes
indexKeys, covering, index_size, slot_size = cache.best_index.get(op["query_hash"], (None, None, None, None))
if indexKeys is None:
indexKeys, covering, index_size, slot_size = self.guess_op_info(design, op)
if self.state.cache_enable:
if self.debug: self.state.cache_miss_ctr.put("best_index")
cache.best_index[op["query_hash"]] = (indexKeys, covering, index_size, slot_size)
elif self.debug:
self.state.cache_hit_ctr.put("best_index")
pageHits = 0
maxHits = 0
indexKeyInsertionPenalty = 0
worst_index_penalty = 0
isRegex = self.state.__getIsOpRegex__(cache, op)
try:
opNodes = self.state.__getNodeIds__(cache, design, op)
except:
if self.debug:
LOG.warn("Failed to estimate touched nodes for op\n%s" % pformat(op))
self.err_ctr += 1
continue
for content in workload.getOpContents(op):
for node_id in opNodes:
lru = self.buffers[node_id]
self.total_op_contents += 1
maxHits += cache.fullscan_pages
indexKeyInsertionPenalty += self.getIndexKeyInsertionPenalty(indexKeys, content)
worst_index_penalty += 1
# If slot size is too large, we consider it as a full page scan
if slot_size >= constants.SLOT_SIZE_LIMIT:
pageHits += cache.fullscan_pages
continue
## FOR
# TODO: Need to handle whether it's a scan or an equality predicate
# TODO: We need to handle when we have a regex predicate. These are tricky
# because they may use an index that will examine all a subset of collections
# and then execute a regex on just those documents.
# If we have a target index, hit that up
if indexKeys and not isRegex: # FIXME
documentId = cache.index_docIds.get(op['query_id'], None)
if documentId is None:
values = catalog.getFieldValues(indexKeys, content)
try:
documentId = hash(values)
except:
if self.debug: LOG.error("Failed to compute index documentIds for op #%d - %s\n%s",\
op['query_id'], values, pformat(op))
self.err_ctr += 1
break
if self.state.cache_enable:
if self.debug: self.state.cache_miss_ctr.put("index_docIds")
cache.index_docIds[op['query_id']] = documentId
elif self.debug:
self.state.cache_hit_ctr.put("index_docIds")
## IF
hits = lru.getDocumentFromIndex(indexKeys, index_size)
# print "hits: ", hits
pageHits += hits
# maxHits += hits if op['type'] == constants.OP_TYPE_INSERT else cache.fullscan_pages
if self.debug:
LOG.debug("Node #%02d: Estimated %d index scan pageHits for op #%d on %s.%s",\
node_id, hits, op["query_id"], op["collection"], indexKeys)
# If we don't have an index, then we know that it's a full scan because the
# collections are unordered
if not indexKeys:
if self.debug:
LOG.debug("No index available for op #%d. Will have to do full scan on '%s'",\
op["query_id"], op["collection"])
pageHits += cache.fullscan_pages
#maxHits += cache.fullscan_pages
# Otherwise, if it's not a covering index, then we need to hit up
# the collection to retrieve the whole document
elif not covering:
documentId = cache.collection_docIds.get(op['query_id'], None)
if documentId is None:
values = catalog.getAllValues(content)
try:
documentId = hash(values)
except:
if self.debug: LOG.error("Failed to compute collection documentIds for op #%d - %s\n%s",\
op['query_id'], values, pformat(op))
self.err_ctr += 1
break
if self.state.cache_enable:
if self.debug: self.state.cache_miss_ctr.put("collection_docIds")
cache.collection_docIds[op['query_id']] = documentId
elif self.debug:
self.state.cache_hit_ctr.put("collection_docIds")
## IF
hits = lru.getDocumentFromCollection(op['collection'], documentId, slot_size)
pageHits += hits
#maxHits += hits if op['type'] == constants.OP_TYPE_INSERT else cache.fullscan_pages
if self.debug:
LOG.debug("Node #%02d: Estimated %d collection scan pageHits for op #%d on %s",\
node_id, hits, op["query_id"], op["collection"])
# We have a covering index, which means that we don't have
# to do a look-up on the document in the collection.
# But we still need to increase maxHits so that the final
# ratio is counted correctly
# Yang seems happy with this...
else:
assert op['type'] != constants.OP_TYPE_INSERT
#maxHits += cache.fullscan_pages
## FOR (node)
## FOR (content)
totalCost += pageHits
totalWorst += maxHits
total_index_penalty += indexKeyInsertionPenalty
total_worst_index_penalty += worst_index_penalty
if self.debug:
LOG.debug("Op #%d on '%s' -> [pageHits:%d / worst:%d]",\
op["query_id"], op["collection"], pageHits, maxHits)
assert pageHits <= maxHits,\
"Estimated pageHits [%d] is greater than worst [%d] for op #%d\n%s" %\
(pageHits, maxHits, op["query_id"], pformat(op))
## FOR (op)
sess_ctr += 1
## FOR (sess)
self.total_index_insertion_penalty = total_index_penalty
# Add index insertion penalty to the total cost
if not self.no_index_insertion_penalty:
totalCost += total_index_penalty
totalWorst += total_worst_index_penalty
## IF
# The final disk cost is the ratio of our estimated disk access cost divided
# by the worst possible cost for this design. If we don't have a worst case,
# then the cost is simply zero
if self.debug: LOG.info("Total operation contents %s, errors %s", self.total_op_contents, self.err_ctr)
assert totalCost <= totalWorst,\
"Estimated total pageHits [%d] is greater than worst case pageHits [%d]" % (totalCost, totalWorst)
final_cost = float(totalCost) / float(totalWorst) if totalWorst else 0
evicted = sum([ lru.evicted for lru in self.buffers ])
LOG.info("Computed Disk Cost: %s [pageHits=%d / worstCase=%d / evicted=%d]",\
final_cost, totalCost, totalWorst, evicted)
return final_cost
def estimateNodes(self, design, op):
"""
For the given operation and a design object,
return an estimate of a list of node ids that we think that
the query will be executed on
"""
results = set()
broadcast = True
shardingKeys = design.getShardKeys(op['collection'])
if self.debug:
LOG.debug("Computing node estimate for Op #%d [sharding=%s]", \
op['query_id'], shardingKeys)
# Inserts always go to a single node
if op['type'] == constants.OP_TYPE_INSERT:
# Get the documents that they're trying to insert and then
# compute their hashes based on the sharding key
# Because there is no logical replication, each document will
# be inserted in one and only one node
for content in workload.getOpContents(op):
values = catalog.getFieldValues(shardingKeys, content)
results.add(self.computeTouchedNode(values))
## FOR
broadcast = False
# Network costs of SELECT, UPDATE, DELETE queries are based off
# of using the sharding key in the predicate
elif len(op['predicates']) > 0:
predicate_types = set()
for k, v in op['predicates'].iteritems():
if design.inShardKeyPattern(op['collection'], k):
broadcast = False
predicate_types.add(v)
if self.debug:
LOG.debug("Op #%d %s Predicates: %s [broadcast=%s / predicateTypes=%s]",\
op['query_id'], op['collection'], op['predicates'], broadcast, list(predicate_types))
## ----------------------------------------------
## PRED_TYPE_REGEX
## ----------------------------------------------
if not broadcast and constants.PRED_TYPE_REGEX in predicate_types:
# Any query that is using a regex on the sharding key must be broadcast to every node
# It's not complete accurate but it's just easier that way
broadcast = True
## ----------------------------------------------
## PRED_TYPE_RANGE
## ----------------------------------------------
elif not broadcast and constants.PRED_TYPE_RANGE in predicate_types:
# If it's a scan, then we need to first figure out what
# node they will start the scan at, and then just approximate
# what it will do by adding N nodes to the touched list starting
# from that first node. We will wrap around to zero
num_touched = self.guessNodes(design, op['collection'], k)
if self.debug:
LOG.info("Estimating that Op #%d on '%s' touches %d nodes",\
op["query_id"], op["collection"], num_touched)
for content in workload.getOpContents(op):
values = catalog.getFieldValues(shardingKeys, content)
if self.debug: LOG.debug("%s -> %s", shardingKeys, values)
try:
node_id = self.computeTouchedNode(values)
except:
if self.debug:
LOG.error(
"Unexpected error when computing touched nodes\n%s"
% pformat(values))
raise
for i in xrange(num_touched):
if node_id >= self.num_nodes: node_id = 0
results.add(node_id)
node_id += 1
## FOR
## FOR
## ----------------------------------------------
## PRED_TYPE_EQUALITY
## ----------------------------------------------
elif not broadcast and constants.PRED_TYPE_EQUALITY in predicate_types:
broadcast = False
for content in workload.getOpContents(op):
values = catalog.getFieldValues(shardingKeys, content)
results.add(self.computeTouchedNode(values))
## FOR
## ----------------------------------------------
## BUSTED!
## ----------------------------------------------
elif not broadcast:
raise Exception("Unexpected predicate types '%s' for op #%d" %
(list(predicate_types), op['query_id']))
## IF
if broadcast:
if self.debug: LOG.debug("Op #%d on '%s' is a broadcast query to all nodes",\
op["query_id"], op["collection"])
map(results.add, xrange(0, self.num_nodes))
map(self.nodeCounts.put, results)
self.op_count += 1
return results
def estimateNodes(self, design, op):
"""
For the given operation and a design object,
return an estimate of a list of node ids that we think that
the query will be executed on
"""
results = set()
broadcast = True
shardingKeys = design.getShardKeys(op['collection'])
if self.debug:
LOG.debug("Computing node estimate for Op #%d [sharding=%s]", \
op['query_id'], shardingKeys)
# Inserts always go to a single node
if op['type'] == constants.OP_TYPE_INSERT:
# Get the documents that they're trying to insert and then
# compute their hashes based on the sharding key
# Because there is no logical replication, each document will
# be inserted in one and only one node
for content in workload.getOpContents(op):
values = catalog.getFieldValues(shardingKeys, content)
results.add(self.computeTouchedNode(values))
## FOR
broadcast = False
# Network costs of SELECT, UPDATE, DELETE queries are based off
# of using the sharding key in the predicate
elif len(op['predicates']) > 0:
predicate_types = set()
for k,v in op['predicates'].iteritems() :
if design.inShardKeyPattern(op['collection'], k) :
broadcast = False
predicate_types.add(v)
if self.debug:
LOG.debug("Op #%d %s Predicates: %s [broadcast=%s / predicateTypes=%s]",\
op['query_id'], op['collection'], op['predicates'], broadcast, list(predicate_types))
## ----------------------------------------------
## PRED_TYPE_REGEX
## ----------------------------------------------
if not broadcast and constants.PRED_TYPE_REGEX in predicate_types:
# Any query that is using a regex on the sharding key must be broadcast to every node
# It's not complete accurate but it's just easier that way
broadcast = True
## ----------------------------------------------
## PRED_TYPE_RANGE
## ----------------------------------------------
elif not broadcast and constants.PRED_TYPE_RANGE in predicate_types:
# If it's a scan, then we need to first figure out what
# node they will start the scan at, and then just approximate
# what it will do by adding N nodes to the touched list starting
# from that first node. We will wrap around to zero
num_touched = self.guessNodes(design, op['collection'], k)
if self.debug:
LOG.info("Estimating that Op #%d on '%s' touches %d nodes",\
op["query_id"], op["collection"], num_touched)
for content in workload.getOpContents(op):
values = catalog.getFieldValues(shardingKeys, content)
if self.debug: LOG.debug("%s -> %s", shardingKeys, values)
try:
node_id = self.computeTouchedNode(values)
except:
if self.debug:
LOG.error("Unexpected error when computing touched nodes\n%s" % pformat(values))
raise
for i in xrange(num_touched):
if node_id >= self.num_nodes: node_id = 0
results.add(node_id)
node_id += 1
## FOR
## FOR
## ----------------------------------------------
## PRED_TYPE_EQUALITY
## ----------------------------------------------
elif not broadcast and constants.PRED_TYPE_EQUALITY in predicate_types:
broadcast = False
for content in workload.getOpContents(op):
values = catalog.getFieldValues(shardingKeys, content)
results.add(self.computeTouchedNode(values))
## FOR
## ----------------------------------------------
## BUSTED!
## ----------------------------------------------
elif not broadcast:
raise Exception("Unexpected predicate types '%s' for op #%d" % (list(predicate_types), op['query_id']))
## IF
if broadcast:
if self.debug: LOG.debug("Op #%d on '%s' is a broadcast query to all nodes",\
op["query_id"], op["collection"])
map(results.add, xrange(0, self.num_nodes))
map(self.nodeCounts.put, results)
self.op_count += 1
return results
def estimateNodes(self, design, op, num_nodes=None):
"""
For the given operation and a design object,
return an estimate of a list of node ids that we think that
the query will be executed on
"""
results = set()
broadcast = True
shardingKeys = design.getShardKeys(op['collection'])
if self.debug:
LOG.debug("Computing node estimate for Op #%d [sharding=%s]", \
op['query_id'], shardingKeys)
# If there are no sharding keys
# All requests on this collection will be routed to the primary node
# We assume the node 0 is the primary node
if len(shardingKeys) == 0:
broadcast = False
results.add(0)
# Inserts always go to a single node
elif op['type'] == constants.OP_TYPE_INSERT:
# Get the documents that they're trying to insert and then
# compute their hashes based on the sharding key
# Because there is no logical replication, each document will
# be inserted in one and only one node
for content in workload.getOpContents(op):
values = catalog.getFieldValues(shardingKeys, content)
results.add(self.computeTouchedNode(op['collection'], shardingKeys, values, num_nodes))
## FOR
broadcast = False
# Network costs of SELECT, UPDATE, DELETE queries are based off
# of using the sharding key in the predicate
elif len(op['predicates']) > 0:
predicate_fields = set()
predicate_types = set()
for k,v in op['predicates'].iteritems() :
if design.inShardKeyPattern(op['collection'], k):
predicate_fields.add(k)
predicate_types.add(v)
if len(predicate_fields) == len(shardingKeys):
broadcast = False
if self.debug:
LOG.debug("Op #%d %s Predicates: %s [broadcast=%s / predicateTypes=%s]",\
op['query_id'], op['collection'], op['predicates'], broadcast, list(predicate_types))
## ----------------------------------------------
## PRED_TYPE_REGEX
## ----------------------------------------------
if not broadcast and constants.PRED_TYPE_REGEX in predicate_types:
# Any query that is using a regex on the sharding key must be broadcast to every node
# It's not complete accurate but it's just easier that way
broadcast = True
## ----------------------------------------------
## PRED_TYPE_RANGE
## ----------------------------------------------
elif not broadcast and constants.PRED_TYPE_RANGE in predicate_types:
broadcast = True
## ----------------------------------------------
## PRED_TYPE_EQUALITY
## ----------------------------------------------
elif not broadcast and constants.PRED_TYPE_EQUALITY in predicate_types:
broadcast = False
for content in workload.getOpContents(op):
values = catalog.getFieldValues(shardingKeys, content)
results.add(self.computeTouchedNode(op['collection'], shardingKeys, values, num_nodes))
## FOR
## ----------------------------------------------
## BUSTED!
## ----------------------------------------------
elif not broadcast:
raise Exception("Unexpected predicate types '%s' for op #%d" % (list(predicate_types), op['query_id']))
## IF
if broadcast:
if self.debug: LOG.debug("Op #%d on '%s' is a broadcast query to all nodes",\
op["query_id"], op["collection"])
map(results.add, xrange(0, self.colNumNodes(num_nodes, op["collection"])))
map(self.nodeCounts.put, results)
self.op_count += 1
return results
