Characterizing memory requirements for queries over continuous data streams
Proceedings of the twenty-first ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Processing XML Streams with Deterministic Automata
ICDT '03 Proceedings of the 9th International Conference on Database Theory
Efficient Filtering of XML Documents for Selective Dissemination of Information
VLDB '00 Proceedings of the 26th International Conference on Very Large Data Bases
Typing and querying XML documents: some complexity bounds
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
The complexity of XPath query evaluation
Proceedings of the twenty-second ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
The complexity of relational query languages (Extended Abstract)
STOC '82 Proceedings of the fourteenth annual ACM symposium on Theory of computing
Some complexity questions related to distributive computing(Preliminary Report)
STOC '79 Proceedings of the eleventh annual ACM symposium on Theory of computing
Optimal aggregation algorithms for middleware
Journal of Computer and System Sciences - Special issu on PODS 2001
Stream processing of XPath queries with predicates
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
XPath queries on streaming data
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
YFilter: Efficient and Scalable Filtering of XML Documents
ICDE '02 Proceedings of the 18th International Conference on Data Engineering
Efficient Filtering of XML Documents with XPath Expressions
ICDE '02 Proceedings of the 18th International Conference on Data Engineering
On the memory requirements of XPath evaluation over XML streams
PODS '04 Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
The VLDB Journal — The International Journal on Very Large Data Bases
Buffering in query evaluation over XML streams
Proceedings of the twenty-fourth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Communication Complexity
Tight lower bounds for query processing on streaming and external memory data
ICALP'05 Proceedings of the 32nd international conference on Automata, Languages and Programming
ACM Computing Surveys (CSUR)
Proceedings of the 12th International Conference on Database Theory
Worst-case optimal algorithm for XPath evaluation over XML streams
Journal of Computer and System Sciences
ACM Transactions on Database Systems (TODS)
Efficient evaluation of generalized tree-pattern queries on XML streams
The VLDB Journal — The International Journal on Very Large Data Bases
Queries on Xml streams with bounded delay and concurrency
Information and Computation
Memory lower bounds for XPath evaluation over XML streams
Journal of Computer and System Sciences
Streamable fragments of forward XPath
CIAA'11 Proceedings of the 16th international conference on Implementation and application of automata
Mixing bottom-up and top-down XPath query evaluation
ADBIS'11 Proceedings of the 15th international conference on Advances in databases and information systems
Chimera: stream-oriented XML filtering/querying engine
DASFAA'10 Proceedings of the 15th international conference on Database Systems for Advanced Applications - Volume Part II
Rewriting XPath queries using materialized XPath views
Journal of Computer and System Sciences
A survey on XML streaming evaluation techniques
The VLDB Journal — The International Journal on Very Large Data Bases
Optimized XPath evaluation for schema-compressed XML data
ADC '12 Proceedings of the Twenty-Third Australasian Database Conference - Volume 124
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The important challenge of evaluating XPath queries over XML streams has sparked much interest in the past few years. A number of algorithms have been proposed, supporting wider fragments of the query language, and exhibiting better performance and memory utilization. Nevertheless, all the algorithms known to date use a prohibitively large amount of memory for certain types of queries. A natural question then is whether this memory bottleneck is inherent or just an artifact of the proposed algorithms. In this paper we initiate the first systematic and theoretical study of lower bounds on the amount of memory required to evaluate XPath queries over XML streams. We present a general lower bound technique, which given a query, specifies the minimum amount of memory that any algorithm evaluating the query on a stream would need to incur. The lower bounds are stated in terms of new graph-theoretic properties of queries. The proofs are based on tools from communication complexity. We then exploit insights learned from the lower bounds to obtain a new algorithm for XPath evaluation on streams. The algorithm uses space close to the optimum. Our algorithm deviates from the standard paradigm of using automata or transducers, thereby avoiding the need to store large transition tables.