Results of 1 - 10 of about 58 for operator (0.001 sec.)
- Metrics 15149
- DuckDB provides a set of metrics that can be used to monitor the performance and health of the database. Metrics are named ⟨group⟩.⟨metric⟩ , e.g., query.total_time or operator.timing . The set of collected metrics is controlled with the tr
...acked_metrics setting , which takes a list of glob patterns, e.g., ['query.*', 'operator.timing'] . By default, all metrics are collected ( ['*'] ). The available metrics, along with their types and units, can b...FROM duckdb_available_metrics(); All Metrics The metrics are organized into the following groups: query system io storage operator optimizer parser planner physical_planner query Metrics Metrics measured over the entire query. Name Type Unit Description...The total number of entries to replay in the WAL storage.write_to_wal_latency double seconds Time spent writing to the WAL operator Metrics Metrics collected for each individual operator in the query plan. These are reported in the operator tree of the p... - https://man.mtool.work/duckdb/2.0/dev/metrics.html
- Subqueries 11373
- Subqueries are parenthesized query expressions that appear as part of a larger, outer query. Subqueries are usually based on SELECT ... FROM , but in DuckDB other query constructs such as PIVOT can also appear as a subquery. Scalar Subquery
...n the section on scalar subqueries , a scalar expression was compared directly to a subquery using the equality comparison operator ( = ). Such direct comparisons only make sense with scalar subqueries. Scalar expressions can still be compared to single-...a whole evaluates to true when the individual comparison results of the expression at the left hand side of the comparison operator with each of the values from the subquery at the right hand side of the comparison operator all evaluate to true : SELECT...s than or equal to 5. The quantifier SOME may be used instead of ANY : ANY and SOME are interchangeable. EXISTS The EXISTS operator tests for the existence of any row inside the subquery. It returns either true when the subquery returns one or more recor... - https://man.mtool.work/duckdb/2.0/sql/expressions/subqueries.html
- IN Operator 11036
- The IN operator checks containment of the left expression inside the collection on the right hand side (RHS). Supported collections on the RHS are tuples, lists, and maps, as well as subqueries that return a single column. The single-column
...s only to subqueries; tuples, lists, and maps may themselves contain composite values. IN (val1, val2, ...) (Tuple) The IN operator on a tuple (val1, val2, ...) returns true if the expression is present in the RHS, false if the expression is not in the R...ECT 'Math' IN ('CS', 'Math', NULL); true SELECT 'English' IN ('CS', 'Math', NULL); NULL IN [val1, val2, ...] (List) The IN operator works on lists according to the semantics used in Python. Unlike for the IN tuple operator , the presence of NULL values o...e in the result: SELECT 'Math' IN ['CS', 'Math', NULL]; true SELECT 'English' IN ['CS', 'Math', NULL]; false IN Map The IN operator works on maps according to the semantics used in Python, i.e., it checks for the presence of keys (not values): SELECT 'ke... - https://man.mtool.work/duckdb/2.0/sql/expressions/in.html
- Pattern Matching 10494
- There are four separate approaches to pattern matching provided by DuckDB: the traditional SQL LIKE operator , the more recent SIMILAR TO operator (added in SQL:1999), a GLOB operator , and POSIX-style regular expressions . LIKE The LIKE ex
...n percent signs or underscores, then the pattern only represents the string itself; in that case LIKE acts like the equals operator. An underscore ( _ ) in pattern stands for (matches) any single character; a percent sign ( % ) matches any sequence of ze...greSQL compatibility. PostgreSQL-style LIKE -style ~~ LIKE !~~ NOT LIKE ~~* ILIKE !~~* NOT ILIKE SIMILAR TO The SIMILAR TO operator returns true or false depending on whether its pattern matches the given string. It is similar to LIKE , except that it in...terprets the pattern using a regular expression . Like LIKE , the SIMILAR TO operator succeeds only if its pattern matches the entire string; this is unlike common regular expression behavior where the patter... - https://man.mtool.work/duckdb/2.0/sql/functions/pattern_matching.html
- Profiling Queries 8738
- DuckDB supports profiling queries via the EXPLAIN and EXPLAIN ANALYZE statements. EXPLAIN To see the query plan of a query without executing it, run: EXPLAIN ⟨query⟩; The output of EXPLAIN contains the estimated cardinalities for each operator
...y, run: EXPLAIN ANALYZE ⟨query⟩; The EXPLAIN ANALYZE statement runs the query, and shows the actual cardinalities for each operator, as well as the cumulative wall-clock time spent in each operator.... - https://man.mtool.work/duckdb/2.0/sql/statements/profiling.html
- EXPLAIN ANALYZE: Profile Queries 8196
- Prepending a query with EXPLAIN ANALYZE both pretty-prints the query plan, and executes it, providing run-time performance numbers and the actual cardinality (number of rows produced) for every operator. EXPLAIN ANALYZE SELECT * FROM tbl; N
...ote that the cumulative wall-clock time that is spent on every operator is shown. When multiple threads are processing the query in parallel, the total processing time of the query may be lower...than the sum of all the times spent on the individual operators. For multi-file reads (e.g., reading multiple Parquet files), the output includes the file names being read. Below is an...rows 0µs │ │ 2 rows 0µs │ ╰─────────────────────────────╯ ╰─────────────────────────────────────────────────────────╯ Each operator shows the number of rows it produced and the time spent in it. Scan operators also show the number of row groups scanned a... - https://man.mtool.work/duckdb/2.0/guides/meta/explain_analyze.html
- Overview of DuckDB Internals 7933
- Tip For a detailed explanation of DuckDB internals, see the Design and Implementation of DuckDB Internals ("DiDi") library entry. On this page is a brief description of the internals of the DuckDB engine. Parser The parser converts a query
...e ParsedExpression represents an expression within a SQL statement. This can be e.g., a reference to a column, an addition operator or a constant value. The type of the ParsedExpression indicates what it represents, e.g., a comparison is represented as a...BoundQueryNode TableRef → BoundStatement ParsedExpression → Expression Logical Planner The logical planner creates LogicalOperator nodes from the bound statements. In this phase, the actual logical query tree is created. Optimizer After the logical plan...passed around in the execution engine. Physical Plan Generator The physical plan generator converts the resulting logical operator tree into a PhysicalOperator tree. Execution In the execution phase, the physical operators are executed to produce the qu... - https://man.mtool.work/duckdb/2.0/internals/overview.html
- Profile and Monitor 7860
- Overview The Go client can observe query execution: it can retrieve per-operator profiling metrics after a query runs, and register a log storage that receives DuckDB's log messages. Both are described below. Profiling Profiling information
...lue and a Children slice of child nodes. Metrics are grouped and named in lowercase: the root's children are the root plan operator, whose metrics include type and timing , followed by one node per metric group, e.g., the query group with total_time . Wa...lk the tree to read them: for _, child := range info.Children { if opType, ok := child.Metrics["type"]; ok { log.Printf("operator: %s, timing: %s", opType, child.Metrics["timing"]) } } All metrics are collected by default; to restrict them, set the tra... - https://man.mtool.work/duckdb/2.0/clients/go/profiling.html
- Pivot Internals 7860
- PIVOT Pivoting is implemented as a combination of SQL query re-writing and a dedicated PhysicalPivot operator for higher performance. Each PIVOT is implemented as set of aggregations into lists and then the dedicated PhysicalPivot operator
...58] US Seattle [2000, 2010, 2020] [564, 608, 738] US New York City [2000, 2010, 2020] [8015, 8175, 8772] The PhysicalPivot operator converts those lists into column names and values to return this result: country name 2000 2010 2020 NL Amsterdam 1005 106... - https://man.mtool.work/duckdb/2.0/internals/pivot.html
- SQL to/from JSON 7728
- DuckDB provides functions to serialize and deserialize SELECT statements between SQL and JSON, as well as executing JSON serialized statements. Function Type Description json_deserialize_sql(json) Scalar Deserialize one or many json seriali
...query_location":9,"query_location_length":0,"function_name":"+","order_bys":{"type":"ORDER_MODIFIER"},"distinct":false,"is_operator":true,"export_state":false,"arguments":[{"expression":{"class":"CONSTANT","type":"VALUE_CONSTANT","query_location":7,"quer...uery_location":23,"query_location_length":0,"function_name":"+","order_bys":{"type":"ORDER_MODIFIER"},"distinct":false,"is_operator":true,"export_state":false,"arguments":[{"expression":{"class":"COLUMN_REF","type":"COLUMN_REF","query_location":21,"query...t":[{"class":"FUNCTION","type":"FUNCTION","query_location":9,"function_name":"+","order_bys":{"type":"ORDER_MODIFIER"},"is_operator":true,"arguments":[{"expression":{"class":"CONSTANT","type":"VALUE_CONSTANT","query_location":7,"query_location_length":1,... - https://man.mtool.work/duckdb/2.0/data/json/sql_to_and_from_json.html
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