ffsshhttiikk Elasticsearch
What I do
I am a distributed, RESTful search and analytics engine built on Apache Lucene. I excel at full-text search, structured search, analytics, logging, and metrics use cases. I provide near-real-time search capabilities, horizontal scalability, and powerful aggregation frameworks for building search experiences, log analytics dashboards, and operational intelligence platforms. I am the backbone of the ELK (Elasticsearch, Logstash, Kibana) stack.
When to use me
- Building full-text search functionality for applications
- Log aggregation and analysis platforms
- Real-time analytics and metrics dashboards
- Application performance monitoring (APM)
- Security information and event management (SIEM)
- Product catalogs and e-commerce search
- Document search and content discovery
- Autocomplete and suggestions systems
- Geospatial search and location-based queries
Core Concepts
- Indices and Documents: Data organized in indices containing JSON documents with unique IDs
- Inverted Index: Data structure enabling fast full-text search by mapping terms to documents
- Mapping: Schema definition defining how documents and fields are stored and indexed
- Analyzers: Tokenization pipelines processing text into searchable terms (standard, custom, language-specific)
- Query DSL: JSON-based query language for complex searches (match, term, range, bool, function_score)
- Aggregations: Framework for computing metrics, buckets, and statistical analysis on data
- Sharding and Replication: Horizontal scaling through index partitioning and data redundancy
- 集群管理: Master nodes for coordination, data nodes for storage, ingest nodes for preprocessing
- 索引生命周期: Hot-Warm-Cold-Delete architecture for managing time-series data
- 跨集群搜索: Cross-cluster search for federated queries across multiple clusters
Code Examples
Basic Index Operations and Document Management
from elasticsearch import Elasticsearch
from elasticsearch.exceptions import NotFoundError, ConflictError
from datetime import datetime
es = Elasticsearch(["http://localhost:9200"])
def create_product_index():
mapping = {
"settings": {
"number_of_shards": 3,
"number_of_replicas": 1,
"analysis": {
"analyzer": {
"product_analyzer": {
"type": "custom",
"tokenizer": "standard",
"filter": ["lowercase", "asciifolding", "product_synonyms"]
}
},
"filter": {
"product_synonyms": {
"type": "synonym",
"synonyms": [
"laptop, notebook, portable computer",
"phone, smartphone, mobile"
]
}
}
}
},
"mappings": {
"properties": {
"name": {"type": "text", "analyzer": "product_analyzer"},
"description": {"type": "text", "analyzer": "standard"},
"SKU": {"type": "keyword"},
"price": {"type": "float"},
"category": {"type": "keyword"},
"in_stock": {"type": "boolean"},
"tags": {"type": "keyword"},
"created_at": {"type": "date"},
"rating": {"type": "float"},
"location": {"type": "geo_point"}
}
}
}
return es.indices.create(index="products", body=mapping)
def index_product(product_data):
product_doc = {
**product_data,
"created_at": datetime.utcnow().isoformat()
}
return es.index(index="products", id=product_data["SKU"], document=product_doc)
def get_product(SKU):
try:
return es.get(index="products", id=SKU)
except NotFoundError:
return None
def update_product(SKU, updates):
return es.update(index="products", id=SKU, doc=updates)
def delete_product(SKU):
return es.delete(index="products", id=SKU)
def bulk_index_products(products):
operations = []
for product in products:
operations.append({"index": {"_index": "products", "_id": product["SKU"]}})
operations.append({**product, "created_at": datetime.utcnow().isoformat()})
return es.bulk(operations=operations, refresh=True)
Search Queries and Filtering
def search_products(query, filters=None, page=1, per_page=20):
search_query = {
"query": {
"bool": {
"must": [
{"multi_match": {
"query": query,
"fields": ["name^3", "description", "tags^2"],
"type": "best_fields",
"fuzziness": "AUTO"
}}
],
"filter": []
}
},
"from": (page - 1) * per_page,
"size": per_page,
"sort": [
{"_score": "desc"},
{"rating": "desc"},
{"price": "asc" if filters.get("sort") == "price_asc" else "desc"}
],
"highlight": {
"fields": {
"name": {},
"description": {"fragment_size": 150}
}
}
}
if filters:
if "category" in filters:
search_query["query"]["bool"]["filter"].append({"term": {"category": filters["category"]}})
if "min_price" in filters:
search_query["query"]["bool"]["filter"].append({"range": {"price": {"gte": filters["min_price"]}}})
if "max_price" in filters:
search_query["query"]["bool"]["filter"].append({"range": {"price": {"lte": filters["max_price"]}}})
if "in_stock" in filters:
search_query["query"]["bool"]["filter"].append({"term": {"in_stock": filters["in_stock"]}})
if "tags" in filters:
search_query["query"]["bool"]["filter"].append({"terms": {"tags": filters["tags"]}})
return es.search(index="products", body=search_query)
def autocomplete(prefix, field="name", limit=10):
return es.search(index="products", body={
"query": {
"match_phrase_prefix": {
field: {"query": prefix, "max_expansions": 50}
}
},
"size": limit,
"_source": ["name", "SKU", "price"]
})
def search_with_function_score(query, boost_factors=None):
return es.search(index="products", body={
"query": {
"function_score": {
"query": {"match_all": {}},
"functions": [
{"field_value_factor": {"field": "rating", "factor": 1.2, "modifier": "log1p", "missing": 1}},
{"filter": {"term": {"in_stock": True}}, "weight": 2}
],
"score_mode": "sum",
"boost_mode": "multiply"
}
},
"size": 50
})
def fuzzy_search(query, fuzziness="AUTO"):
return es.search(index="products", body={
"query": {
"multi_match": {
"query": query,
"fields": ["name", "description"],
"fuzziness": fuzziness
}
}
})
def find_similar_products(SKU, limit=10):
return es.search(index="products", body={
"query": {
"more_like_this": {
"fields": ["name", "description", "tags"],
"like": [{"_index": "products", "_id": SKU}],
"min_term_freq": 1,
"min_doc_freq": 1,
"max_query_terms": 25
}
},
"size": limit
})
Aggregations and Analytics
def get_product_aggregations(category_filter=None):
query = {"match_all": {}} if not category_filter else {"term": {"category": category_filter}}
return es.search(index="products", body={
"query": query,
"size": 0,
"aggs": {
"categories": {"terms": {"field": "category", "size": 50}},
"price_stats": {"stats": {"field": "price"}},
"price_ranges": {
"range": {
"field": "price",
"ranges": [
{"key": "budget", "to": 50},
{"key": "mid-range", "from": 50, "to": 200},
{"key": "premium", "from": 200}
]
}
},
"avg_rating_by_category": {
"terms": {"field": "category", "size": 20},
"aggs": {
"avg_rating": {"avg": {"field": "rating"}}
}
},
"top_tags": {"terms": {"field": "tags", "size": 30}},
"stock_status": {"terms": {"field": "in_stock"}}
}
})
def get_sales_analytics(start_date, end_date):
return es.search(index="sales", body={
"query": {
"range": {"created_at": {"gte": start_date, "lte": end_date}}
},
"size": 0,
"aggs": {
"daily_sales": {
"date_histogram": {
"field": "created_at",
"calendar_interval": "day"
},
"aggs": {
"total_revenue": {"sum": {"field": "amount"}},
"avg_order_value": {"avg": {"field": "amount"}},
"unique_customers": {"cardinality": {"field": "customer_id"}}
}
},
"by_category": {
"terms": {"field": "category"},
"aggs": {
"revenue": {"sum": {"field": "amount"}}
}
}
}
})
def get_top_selling_products(limit=10):
return es.search(index="sales", body={
"query": {"match_all": {}},
"size": 0,
"aggs": {
"products": {
"terms": {"field": "product_id", "size": limit},
"aggs": {
"total_revenue": {"sum": {"field": "amount"}},
"total_quantity": {"sum": {"field": "quantity"}}
}
}
}
})
def get_time_series_metrics(metric_field, interval="1h"):
return es.search(index="metrics", body={
"query": {"match_all": {}},
"size": 0,
"aggs": {
"timeseries": {
"date_histogram": {"field": "timestamp", "calendar_interval": interval},
"aggs": {
"avg_value": {"avg": {"field": metric_field}},
"max_value": {"max": {"field": metric_field}},
"min_value": {"min": {"field": metric_field}},
"percentiles": {"percentiles": {"field": metric_field, "percents": [50, 90, 95, 99]}}
}
}
}
})
Geospatial Queries
def search_nearby_stores(location, radius_km=10, limit=20):
return es.search(index="stores", body={
"query": {
"bool": {
"must": {"match_all": {}},
"filter": {
"geo_distance": {
"distance": f"{radius_km}km",
"location": location
}
}
}
},
"sort": [
{"_geo_distance": {
"location": location,
"order": "asc",
"unit": "km"
}}
],
"size": limit
})
def search_stores_in_bounds(top_left, bottom_right):
return es.search(index="stores", body={
"query": {
"geo_bounding_box": {
"location": {
"top_left": top_left,
"bottom_right": bottom_right
}
}
}
})
def aggregate_by_location(grid_size="50km"):
return es.search(index="stores", body={
"size": 0,
"aggs": {
"store_grid": {
"geotile_grid": {
"field": "location",
"precision": 12,
"size": 1000
},
"aggs": {
"avg_rating": {"avg": {"field": "rating"}},
"store_count": {"value_count": {"field": "id"}}
}
}
}
})
def find_stores_within_polygon(polygon):
return es.search(index="stores", body={
"query": {
"geo_polygon": {
"location": {"points": polygon}
}
}
})
Index Management and Optimization
def refresh_index(index_name):
return es.indices.refresh(index=index_name)
def force_merge_index(index_name, max_segments=1):
return es.indices.forcemerge(index=index_name, max_num_segments=max_segments)
def update_index_settings(index_name, settings):
return es.indices.put_settings(index=index_name, body=settings)
def get_index_stats(index_name):
return es.indices.stats(index=index_name)
def create_index_alias(index_name, alias_name):
return es.indices.put_alias(index=index_name, name=alias_name)
def rollover_index(alias_name, max_age="7d", max_docs=100000):
return es.indices.rollover(alias=alias_name, conditions={
"max_age": max_age,
"max_docs": max_docs
})
def reindex_from_remote(source_index, dest_index):
return es.reindex(body={
"source": {"remote": {"host": "http://old-cluster:9200"}, "index": source_index},
"dest": {"index": dest_index}
}, wait_for_completion=True)
def delete_old_indices(pattern="logs-*", older_than_days=30):
from datetime import datetime, timedelta
cutoff = datetime.utcnow() - timedelta(days=older_than_days)
indices = es.cat.indices(index=pattern, h="index,creation.date").splitlines()
deleted = []
for line in indices:
if line.strip():
parts = line.split()
index_name = parts[0]
creation_date = datetime.fromisoformat(parts[1].replace("T", " ").split(".")[0])
if creation_date < cutoff:
es.indices.delete(index=index_name)
deleted.append(index_name)
return deleted
Best Practices
- Design Index Mapping Carefully: Define mappings upfront; changing field types after data exists is costly
- Use Appropriate Analyzers: Choose analyzers based on language and use case; test with _analyze API
- Implement Index Lifecycle Management: Use ILM policies for time-series data (hot-warm-cold-delete)
- Optimize Shard Count: Aim for shards between 20-50GB; avoid too many small shards
- Use Query Caching: Leverage query cache and request cache for repeated aggregations
- Implement Proper Refresh Intervals: Balance index refresh rate with indexing throughput needs
- Monitor Cluster Health: Track cluster stats, shard allocation, and node resource utilization
- Use Bulk API for Indexing: Batch documents for bulk indexing to improve throughput
- Implement Cross-Cluster Search: For multi-region or multi-environment queries
- Secure Your Cluster: Enable authentication, TLS/SSL, and implement network policies