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This patch makes several changes that improve the consistency of representation of lists of statements. It's always been the case that the output of parse analysis is a list of Query nodes, whatever the types of the individual statements in the list. This patch brings similar consistency to the outputs of raw parsing and planning steps: * The output of raw parsing is now always a list of RawStmt nodes; the statement-type-dependent nodes are one level down from that. * The output of pg_plan_queries() is now always a list of PlannedStmt nodes, even for utility statements. In the case of a utility statement, "planning" just consists of wrapping a CMD_UTILITY PlannedStmt around the utility node. This list representation is now used in Portal and CachedPlan plan lists, replacing the former convention of intermixing PlannedStmts with bare utility-statement nodes. Now, every list of statements has a consistent head-node type depending on how far along it is in processing. This allows changing many places that formerly used generic "Node *" pointers to use a more specific pointer type, thus reducing the number of IsA() tests and casts needed, as well as improving code clarity. Also, the post-parse-analysis representation of DECLARE CURSOR is changed so that it looks more like EXPLAIN, PREPARE, etc. That is, the contained SELECT remains a child of the DeclareCursorStmt rather than getting flipped around to be the other way. It's now true for both Query and PlannedStmt that utilityStmt is non-null if and only if commandType is CMD_UTILITY. That allows simplifying a lot of places that were testing both fields. (I think some of those were just defensive programming, but in many places, it was actually necessary to avoid confusing DECLARE CURSOR with SELECT.) Because PlannedStmt carries a canSetTag field, we're also able to get rid of some ad-hoc rules about how to reconstruct canSetTag for a bare utility statement; specifically, the assumption that a utility is canSetTag if and only if it's the only one in its list. While I see no near-term need for relaxing that restriction, it's nice to get rid of the ad-hocery. The API of ProcessUtility() is changed so that what it's passed is the wrapper PlannedStmt not just the bare utility statement. This will affect all users of ProcessUtility_hook, but the changes are pretty trivial; see the affected contrib modules for examples of the minimum change needed. (Most compilers should give pointer-type-mismatch warnings for uncorrected code.) There's also a change in the API of ExplainOneQuery_hook, to pass through cursorOptions instead of expecting hook functions to know what to pick. This is needed because of the DECLARE CURSOR changes, but really should have been done in 9.6; it's unlikely that any extant hook functions know about using CURSOR_OPT_PARALLEL_OK. Finally, teach gram.y to save statement boundary locations in RawStmt nodes, and pass those through to Query and PlannedStmt nodes. This allows more intelligent handling of cases where a source query string contains multiple statements. This patch doesn't actually do anything with the information, but a follow-on patch will. (Passing this information through cleanly is the true motivation for these changes; while I think this is all good cleanup, it's unlikely we'd have bothered without this end goal.) catversion bump because addition of location fields to struct Query affects stored rules. This patch is by me, but it owes a good deal to Fabien Coelho who did a lot of preliminary work on the problem, and also reviewed the patch. Discussion: https://postgr.es/m/alpine.DEB.2.20.1612200926310.29821@lancre
103 lines
3.7 KiB
C
103 lines
3.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* explain.h
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* prototypes for explain.c
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*
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* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994-5, Regents of the University of California
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*
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* src/include/commands/explain.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef EXPLAIN_H
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#define EXPLAIN_H
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#include "executor/executor.h"
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#include "lib/stringinfo.h"
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#include "parser/parse_node.h"
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typedef enum ExplainFormat
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{
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EXPLAIN_FORMAT_TEXT,
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EXPLAIN_FORMAT_XML,
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EXPLAIN_FORMAT_JSON,
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EXPLAIN_FORMAT_YAML
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} ExplainFormat;
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typedef struct ExplainState
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{
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StringInfo str; /* output buffer */
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/* options */
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bool verbose; /* be verbose */
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bool analyze; /* print actual times */
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bool costs; /* print estimated costs */
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bool buffers; /* print buffer usage */
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bool timing; /* print detailed node timing */
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bool summary; /* print total planning and execution timing */
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ExplainFormat format; /* output format */
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/* state for output formatting --- not reset for each new plan tree */
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int indent; /* current indentation level */
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List *grouping_stack; /* format-specific grouping state */
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/* state related to the current plan tree (filled by ExplainPrintPlan) */
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PlannedStmt *pstmt; /* top of plan */
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List *rtable; /* range table */
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List *rtable_names; /* alias names for RTEs */
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List *deparse_cxt; /* context list for deparsing expressions */
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Bitmapset *printed_subplans; /* ids of SubPlans we've printed */
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} ExplainState;
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/* Hook for plugins to get control in ExplainOneQuery() */
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typedef void (*ExplainOneQuery_hook_type) (Query *query,
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int cursorOptions,
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IntoClause *into,
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ExplainState *es,
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const char *queryString,
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ParamListInfo params);
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extern PGDLLIMPORT ExplainOneQuery_hook_type ExplainOneQuery_hook;
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/* Hook for plugins to get control in explain_get_index_name() */
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typedef const char *(*explain_get_index_name_hook_type) (Oid indexId);
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extern PGDLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
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extern void ExplainQuery(ParseState *pstate, ExplainStmt *stmt, const char *queryString,
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ParamListInfo params, DestReceiver *dest);
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extern ExplainState *NewExplainState(void);
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extern TupleDesc ExplainResultDesc(ExplainStmt *stmt);
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extern void ExplainOneUtility(Node *utilityStmt, IntoClause *into,
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ExplainState *es,
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const char *queryString, ParamListInfo params);
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extern void ExplainOnePlan(PlannedStmt *plannedstmt, IntoClause *into,
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ExplainState *es, const char *queryString,
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ParamListInfo params, const instr_time *planduration);
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extern void ExplainPrintPlan(ExplainState *es, QueryDesc *queryDesc);
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extern void ExplainPrintTriggers(ExplainState *es, QueryDesc *queryDesc);
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extern void ExplainQueryText(ExplainState *es, QueryDesc *queryDesc);
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extern void ExplainBeginOutput(ExplainState *es);
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extern void ExplainEndOutput(ExplainState *es);
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extern void ExplainSeparatePlans(ExplainState *es);
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extern void ExplainPropertyList(const char *qlabel, List *data,
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ExplainState *es);
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extern void ExplainPropertyListNested(const char *qlabel, List *data,
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ExplainState *es);
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extern void ExplainPropertyText(const char *qlabel, const char *value,
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ExplainState *es);
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extern void ExplainPropertyInteger(const char *qlabel, int value,
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ExplainState *es);
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extern void ExplainPropertyLong(const char *qlabel, long value,
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ExplainState *es);
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extern void ExplainPropertyFloat(const char *qlabel, double value, int ndigits,
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ExplainState *es);
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extern void ExplainPropertyBool(const char *qlabel, bool value,
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ExplainState *es);
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#endif /* EXPLAIN_H */
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