database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-02 04:21:28 +03:00
Code Activity

Restructure SELECT INTO's parsetree representation into CreateTableAsStmt.

Browse Source 
Making this operation look like a utility statement seems generally a good
idea, and particularly so in light of the desire to provide command
triggers for utility statements.  The original choice of representing it as
SELECT with an IntoClause appendage had metastasized into rather a lot of
places, unfortunately, so that this patch is a great deal more complicated
than one might at first expect.

In particular, keeping EXPLAIN working for SELECT INTO and CREATE TABLE AS
subcommands required restructuring some EXPLAIN-related APIs.  Add-on code
that calls ExplainOnePlan or ExplainOneUtility, or uses
ExplainOneQuery_hook, will need adjustment.

Also, the cases PREPARE ... SELECT INTO and CREATE RULE ... SELECT INTO,
which formerly were accepted though undocumented, are no longer accepted.
The PREPARE case can be replaced with use of CREATE TABLE AS EXECUTE.
The CREATE RULE case doesn't seem to have much real-world use (since the
rule would work only once before failing with "table already exists"),
so we'll not bother with that one.

Both SELECT INTO and CREATE TABLE AS still return a command tag of
"SELECT nnnn".  There was some discussion of returning "CREATE TABLE nnnn",
but for the moment backwards compatibility wins the day.

Andres Freund and Tom Lane
This commit is contained in:
Tom Lane
2012-03-19 21:37:19 -04:00
parent 77503a7638
commit 9dbf2b7d75
47 changed files with 963 additions and 729 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
src/backend/tcop/dest.c
View File

@@ -31,7 +31,7 @@
#include "access/printtup.h"
#include "access/xact.h"
#include "commands/copy.h"
#include "executor/executor.h"
#include "commands/createas.h"
#include "executor/functions.h"
#include "executor/tstoreReceiver.h"
#include "libpq/libpq.h"
@@ -118,7 +118,7 @@ CreateDestReceiver(CommandDest dest)
return CreateTuplestoreDestReceiver();
case DestIntoRel:
return CreateIntoRelDestReceiver();
return CreateIntoRelDestReceiver(NULL);
case DestCopyOut:
return CreateCopyDestReceiver();

6
src/backend/tcop/postgres.c
View File

@@ -624,7 +624,7 @@ pg_analyze_and_rewrite_params(Node *parsetree,
pstate->p_sourcetext = query_string;
(*parserSetup) (pstate, parserSetupArg);
query = transformStmt(pstate, parsetree);
query = transformTopLevelStmt(pstate, parsetree);
free_parsestate(pstate);
@@ -975,7 +975,7 @@ exec_simple_query(const char *query_string)
* end up being able to do this, keeping the parse/plan snapshot around
* until after we start the portal doesn't cost much.
*/
PortalStart(portal, NULL, snapshot_set);
PortalStart(portal, NULL, 0, snapshot_set);
/* Done with the snapshot used for parsing/planning */
if (snapshot_set)
@@ -1709,7 +1709,7 @@ exec_bind_message(StringInfo input_message)
* for query execution (currently, reuse will only occur if
* PORTAL_ONE_SELECT mode is chosen).
*/
PortalStart(portal, params, snapshot_set);
PortalStart(portal, params, 0, snapshot_set);
/* Done with the snapshot used for parameter I/O and parsing/planning */
if (snapshot_set)

39
src/backend/tcop/pquery.c
View File

@@ -260,8 +260,7 @@ ChoosePortalStrategy(List *stmts)
if (query->canSetTag)
{
if (query->commandType == CMD_SELECT &&
query->utilityStmt == NULL &&
query->intoClause == NULL)
query->utilityStmt == NULL)
{
if (query->hasModifyingCTE)
return PORTAL_ONE_MOD_WITH;
@@ -285,8 +284,7 @@ ChoosePortalStrategy(List *stmts)
if (pstmt->canSetTag)
{
if (pstmt->commandType == CMD_SELECT &&
pstmt->utilityStmt == NULL &&
pstmt->intoClause == NULL)
pstmt->utilityStmt == NULL)
{
if (pstmt->hasModifyingCTE)
return PORTAL_ONE_MOD_WITH;
@@ -395,8 +393,7 @@ FetchStatementTargetList(Node *stmt)
else
{
if (query->commandType == CMD_SELECT &&
query->utilityStmt == NULL &&
query->intoClause == NULL)
query->utilityStmt == NULL)
return query->targetList;
if (query->returningList)
return query->returningList;
@@ -408,8 +405,7 @@ FetchStatementTargetList(Node *stmt)
PlannedStmt *pstmt = (PlannedStmt *) stmt;
if (pstmt->commandType == CMD_SELECT &&
pstmt->utilityStmt == NULL &&
pstmt->intoClause == NULL)
pstmt->utilityStmt == NULL)
return pstmt->planTree->targetlist;
if (pstmt->hasReturning)
return pstmt->planTree->targetlist;
@@ -430,7 +426,6 @@ FetchStatementTargetList(Node *stmt)
ExecuteStmt *estmt = (ExecuteStmt *) stmt;
PreparedStatement *entry;
Assert(!estmt->into);
entry = FetchPreparedStatement(estmt->name, true);
return FetchPreparedStatementTargetList(entry);
}
@@ -442,9 +437,15 @@ FetchStatementTargetList(Node *stmt)
* Prepare a portal for execution.
*
* Caller must already have created the portal, done PortalDefineQuery(),
* and adjusted portal options if needed. If parameters are needed by
* the query, they must be passed in here (caller is responsible for
* giving them appropriate lifetime).
* and adjusted portal options if needed.
*
* If parameters are needed by the query, they must be passed in "params"
* (caller is responsible for giving them appropriate lifetime).
*
* The caller can also provide an initial set of "eflags" to be passed to
* ExecutorStart (but note these can be modified internally, and they are
* currently only honored for PORTAL_ONE_SELECT portals). Most callers
* should simply pass zero.
*
* The use_active_snapshot parameter is currently used only for
* PORTAL_ONE_SELECT portals. If it is true, the active snapshot will
@@ -456,14 +457,15 @@ FetchStatementTargetList(Node *stmt)
* tupdesc (if any) is known.
*/
void
PortalStart(Portal portal, ParamListInfo params, bool use_active_snapshot)
PortalStart(Portal portal, ParamListInfo params,
int eflags, bool use_active_snapshot)
{
Portal saveActivePortal;
ResourceOwner saveResourceOwner;
MemoryContext savePortalContext;
MemoryContext oldContext;
QueryDesc *queryDesc;
int eflags;
int myeflags;
AssertArg(PortalIsValid(portal));
AssertState(portal->status == PORTAL_DEFINED);
@@ -517,17 +519,18 @@ PortalStart(Portal portal, ParamListInfo params, bool use_active_snapshot)
/*
* If it's a scrollable cursor, executor needs to support
* REWIND and backwards scan.
* REWIND and backwards scan, as well as whatever the caller
* might've asked for.
*/
if (portal->cursorOptions & CURSOR_OPT_SCROLL)
eflags = EXEC_FLAG_REWIND | EXEC_FLAG_BACKWARD;
myeflags = eflags | EXEC_FLAG_REWIND | EXEC_FLAG_BACKWARD;
else
eflags = 0; /* default run-to-completion flags */
myeflags = eflags;
/*
* Call ExecutorStart to prepare the plan for execution
*/
ExecutorStart(queryDesc, eflags);
ExecutorStart(queryDesc, myeflags);
/*
* This tells PortalCleanup to shut down the executor

81
src/backend/tcop/utility.c
View File

@@ -29,6 +29,7 @@
#include "commands/collationcmds.h"
#include "commands/conversioncmds.h"
#include "commands/copy.h"
#include "commands/createas.h"
#include "commands/dbcommands.h"
#include "commands/defrem.h"
#include "commands/discard.h"
@@ -127,9 +128,7 @@ CommandIsReadOnly(Node *parsetree)
switch (stmt->commandType)
{
case CMD_SELECT:
if (stmt->intoClause != NULL)
return false; /* SELECT INTO */
else if (stmt->rowMarks != NIL)
if (stmt->rowMarks != NIL)
return false; /* SELECT FOR UPDATE/SHARE */
else if (stmt->hasModifyingCTE)
return false; /* data-modifying CTE */
@@ -198,6 +197,7 @@ check_xact_readonly(Node *parsetree)
case T_CreateSchemaStmt:
case T_CreateSeqStmt:
case T_CreateStmt:
case T_CreateTableAsStmt:
case T_CreateTableSpaceStmt:
case T_CreateTrigStmt:
case T_CompositeTypeStmt:
@@ -673,7 +673,8 @@ standard_ProcessUtility(Node *parsetree,
break;
case T_ExecuteStmt:
ExecuteQuery((ExecuteStmt *) parsetree, queryString, params,
ExecuteQuery((ExecuteStmt *) parsetree, NULL,
queryString, params,
dest, completionTag);
break;
@@ -1036,6 +1037,11 @@ standard_ProcessUtility(Node *parsetree,
ExplainQuery((ExplainStmt *) parsetree, queryString, params, dest);
break;
case T_CreateTableAsStmt:
ExecCreateTableAs((CreateTableAsStmt *) parsetree,
queryString, params, completionTag);
break;
case T_VariableSetStmt:
ExecSetVariableStmt((VariableSetStmt *) parsetree);
break;
@@ -1230,8 +1236,6 @@ UtilityReturnsTuples(Node *parsetree)
ExecuteStmt *stmt = (ExecuteStmt *) parsetree;
PreparedStatement *entry;
if (stmt->into)
return false;
entry = FetchPreparedStatement(stmt->name, false);
if (!entry)
return false; /* not our business to raise error */
@@ -1282,8 +1286,6 @@ UtilityTupleDescriptor(Node *parsetree)
ExecuteStmt *stmt = (ExecuteStmt *) parsetree;
PreparedStatement *entry;
if (stmt->into)
return NULL;
entry = FetchPreparedStatement(stmt->name, false);
if (!entry)
return NULL; /* not our business to raise error */
@@ -1317,9 +1319,8 @@ QueryReturnsTuples(Query *parsetree)
switch (parsetree->commandType)
{
case CMD_SELECT:
/* returns tuples ... unless it's DECLARE CURSOR or SELECT INTO */
if (parsetree->utilityStmt == NULL &&
parsetree->intoClause == NULL)
/* returns tuples ... unless it's DECLARE CURSOR */
if (parsetree->utilityStmt == NULL)
return true;
break;
case CMD_INSERT:
@@ -1341,6 +1342,37 @@ QueryReturnsTuples(Query *parsetree)
#endif
/*
* UtilityContainsQuery
* Return the contained Query, or NULL if there is none
*
* Certain utility statements, such as EXPLAIN, contain a Query.
* This function encapsulates knowledge of exactly which ones do.
* We assume it is invoked only on already-parse-analyzed statements
* (else the contained parsetree isn't a Query yet).
*/
Query *
UtilityContainsQuery(Node *parsetree)
{
switch (nodeTag(parsetree))
{
case T_ExplainStmt:
Assert(IsA(((ExplainStmt *) parsetree)->query, Query));
return (Query *) ((ExplainStmt *) parsetree)->query;
case T_CreateTableAsStmt:
/* might or might not contain a Query ... */
if (IsA(((CreateTableAsStmt *) parsetree)->query, Query))
return (Query *) ((CreateTableAsStmt *) parsetree)->query;
Assert(IsA(((CreateTableAsStmt *) parsetree)->query, ExecuteStmt));
return NULL;
default:
return NULL;
}
}
/*
* AlterObjectTypeCommandTag
* helper function for CreateCommandTag
@@ -1907,6 +1939,13 @@ CreateCommandTag(Node *parsetree)
tag = "EXPLAIN";
break;
case T_CreateTableAsStmt:
if (((CreateTableAsStmt *) parsetree)->is_select_into)
tag = "SELECT INTO";
else
tag = "CREATE TABLE AS";
break;
case T_VariableSetStmt:
switch (((VariableSetStmt *) parsetree)->kind)
{
@@ -2060,8 +2099,6 @@ CreateCommandTag(Node *parsetree)
Assert(IsA(stmt->utilityStmt, DeclareCursorStmt));
tag = "DECLARE CURSOR";
}
else if (stmt->intoClause != NULL)
tag = "SELECT INTO";
else if (stmt->rowMarks != NIL)
{
/* not 100% but probably close enough */
@@ -2110,8 +2147,6 @@ CreateCommandTag(Node *parsetree)
Assert(IsA(stmt->utilityStmt, DeclareCursorStmt));
tag = "DECLARE CURSOR";
}
else if (stmt->intoClause != NULL)
tag = "SELECT INTO";
else if (stmt->rowMarks != NIL)
{
/* not 100% but probably close enough */
@@ -2179,7 +2214,7 @@ GetCommandLogLevel(Node *parsetree)
case T_SelectStmt:
if (((SelectStmt *) parsetree)->intoClause)
lev = LOGSTMT_DDL; /* CREATE AS, SELECT INTO */
lev = LOGSTMT_DDL; /* SELECT INTO */
else
lev = LOGSTMT_ALL;
break;
@@ -2429,6 +2464,10 @@ GetCommandLogLevel(Node *parsetree)
}
break;
case T_CreateTableAsStmt:
lev = LOGSTMT_DDL;
break;
case T_VariableSetStmt:
lev = LOGSTMT_ALL;
break;
@@ -2529,10 +2568,7 @@ GetCommandLogLevel(Node *parsetree)
switch (stmt->commandType)
{
case CMD_SELECT:
if (stmt->intoClause != NULL)
lev = LOGSTMT_DDL; /* CREATE AS, SELECT INTO */
else
lev = LOGSTMT_ALL; /* SELECT or DECLARE CURSOR */
lev = LOGSTMT_ALL;
break;
case CMD_UPDATE:
@@ -2558,10 +2594,7 @@ GetCommandLogLevel(Node *parsetree)
switch (stmt->commandType)
{
case CMD_SELECT:
if (stmt->intoClause != NULL)
lev = LOGSTMT_DDL; /* CREATE AS, SELECT INTO */
else
lev = LOGSTMT_ALL; /* SELECT or DECLARE CURSOR */
lev = LOGSTMT_ALL;
break;
case CMD_UPDATE: