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Support data-modifying commands (INSERT/UPDATE/DELETE) in WITH.

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This patch implements data-modifying WITH queries according to the
semantics that the updates all happen with the same command counter value,
and in an unspecified order.  Therefore one WITH clause can't see the
effects of another, nor can the outer query see the effects other than
through the RETURNING values.  And attempts to do conflicting updates will
have unpredictable results.  We'll need to document all that.

This commit just fixes the code; documentation updates are waiting on
author.

Marko Tiikkaja and Hitoshi Harada
This commit is contained in:
Tom Lane
2011-02-25 18:56:23 -05:00
parent 0056066d06
commit 389af95155
38 changed files with 1323 additions and 161 deletions
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36
src/backend/tcop/pquery.c
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@ -143,8 +143,8 @@ FreeQueryDesc(QueryDesc *qdesc)
/*
* ProcessQuery
* Execute a single plannable query within a PORTAL_MULTI_QUERY
* or PORTAL_ONE_RETURNING portal
* Execute a single plannable query within a PORTAL_MULTI_QUERY,
* PORTAL_ONE_RETURNING, or PORTAL_ONE_MOD_WITH portal
*
* plan: the plan tree for the query
* sourceText: the source text of the query
@ -263,6 +263,7 @@ ChoosePortalStrategy(List *stmts)
* PORTAL_ONE_SELECT and PORTAL_UTIL_SELECT need only consider the
* single-statement case, since there are no rewrite rules that can add
* auxiliary queries to a SELECT or a utility command.
* PORTAL_ONE_MOD_WITH likewise allows only one top-level statement.
*/
if (list_length(stmts) == 1)
{
@ -277,7 +278,12 @@ ChoosePortalStrategy(List *stmts)
if (query->commandType == CMD_SELECT &&
query->utilityStmt == NULL &&
query->intoClause == NULL)
return PORTAL_ONE_SELECT;
{
if (query->hasModifyingCTE)
return PORTAL_ONE_MOD_WITH;
else
return PORTAL_ONE_SELECT;
}
if (query->commandType == CMD_UTILITY &&
query->utilityStmt != NULL)
{
@ -297,7 +303,12 @@ ChoosePortalStrategy(List *stmts)
if (pstmt->commandType == CMD_SELECT &&
pstmt->utilityStmt == NULL &&
pstmt->intoClause == NULL)
return PORTAL_ONE_SELECT;
{
if (pstmt->hasModifyingCTE)
return PORTAL_ONE_MOD_WITH;
else
return PORTAL_ONE_SELECT;
}
}
}
else
@ -562,6 +573,7 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot)
break;
case PORTAL_ONE_RETURNING:
case PORTAL_ONE_MOD_WITH:
/*
* We don't start the executor until we are told to run the
@ -572,7 +584,6 @@ PortalStart(Portal portal, ParamListInfo params, Snapshot snapshot)
pstmt = (PlannedStmt *) PortalGetPrimaryStmt(portal);
Assert(IsA(pstmt, PlannedStmt));
Assert(pstmt->hasReturning);
portal->tupDesc =
ExecCleanTypeFromTL(pstmt->planTree->targetlist,
false);
@ -780,12 +791,13 @@ PortalRun(Portal portal, long count, bool isTopLevel,
{
case PORTAL_ONE_SELECT:
case PORTAL_ONE_RETURNING:
case PORTAL_ONE_MOD_WITH:
case PORTAL_UTIL_SELECT:
/*
* If we have not yet run the command, do so, storing its
* results in the portal's tuplestore. Do this only for the
* PORTAL_ONE_RETURNING and PORTAL_UTIL_SELECT cases.
* results in the portal's tuplestore. But we don't do that
* for the PORTAL_ONE_SELECT case.
*/
if (portal->strategy != PORTAL_ONE_SELECT && !portal->holdStore)
FillPortalStore(portal, isTopLevel);
@ -879,8 +891,8 @@ PortalRun(Portal portal, long count, bool isTopLevel,
/*
* PortalRunSelect
* Execute a portal's query in PORTAL_ONE_SELECT mode, and also
* when fetching from a completed holdStore in PORTAL_ONE_RETURNING
* and PORTAL_UTIL_SELECT cases.
* when fetching from a completed holdStore in PORTAL_ONE_RETURNING,
* PORTAL_ONE_MOD_WITH, and PORTAL_UTIL_SELECT cases.
*
* This handles simple N-rows-forward-or-backward cases. For more complex
* nonsequential access to a portal, see PortalRunFetch.
@ -1031,7 +1043,8 @@ PortalRunSelect(Portal portal,
* FillPortalStore
* Run the query and load result tuples into the portal's tuple store.
*
* This is used for PORTAL_ONE_RETURNING and PORTAL_UTIL_SELECT cases only.
* This is used for PORTAL_ONE_RETURNING, PORTAL_ONE_MOD_WITH, and
* PORTAL_UTIL_SELECT cases only.
*/
static void
FillPortalStore(Portal portal, bool isTopLevel)
@ -1051,6 +1064,7 @@ FillPortalStore(Portal portal, bool isTopLevel)
switch (portal->strategy)
{
case PORTAL_ONE_RETURNING:
case PORTAL_ONE_MOD_WITH:
/*
* Run the portal to completion just as for the default
@ -1392,6 +1406,7 @@ PortalRunFetch(Portal portal,
break;
case PORTAL_ONE_RETURNING:
case PORTAL_ONE_MOD_WITH:
case PORTAL_UTIL_SELECT:
/*
@ -1455,6 +1470,7 @@ DoPortalRunFetch(Portal portal,
Assert(portal->strategy == PORTAL_ONE_SELECT ||
portal->strategy == PORTAL_ONE_RETURNING ||
portal->strategy == PORTAL_ONE_MOD_WITH ||
portal->strategy == PORTAL_UTIL_SELECT);
switch (fdirection)