/*
* Compose and dispatch the MPPEXEC commands corresponding to a plan tree
* within a complete parallel plan. (A plan tree will correspond either
* to an initPlan or to the main plan.)
*
* If cancelOnError is true, then any dispatching error, a cancellation
* request from the client, or an error from any of the associated QEs,
* may cause the unfinished portion of the plan to be abandoned or canceled;
* and in the event this occurs before all gangs have been dispatched, this
* function does not return, but waits for all QEs to stop and exits to
* the caller's error catcher via ereport(ERROR,...).Otherwise this
* function returns normally and errors are not reported until later.
*
* If cancelOnError is false, the plan is to be dispatched as fully as
* possible and the QEs allowed to proceed regardless of cancellation
* requests, errors or connection failures from other QEs, etc.
*
* The CdbDispatchResults objects allocated for the plan are returned
* in *pPrimaryResults. The caller, after calling
* CdbCheckDispatchResult(), can examine the CdbDispatchResults
* objects, can keep them as long as needed, and ultimately must free
* them with cdbdisp_destroyDispatcherState() prior to deallocation of
* the caller's memory context. Callers should use PG_TRY/PG_CATCH to
* ensure proper cleanup.
*
* To wait for completion, check for errors, and clean up, it is
* suggested that the caller use cdbdisp_finishCommand().
*
* Note that the slice tree dispatched is the one specified in the EState
* of the argument QueryDesc as es_cur__slice.
*
* Note that the QueryDesc params must include PARAM_EXEC_REMOTE parameters
* containing the values of any initplans required by the slice to be run.
* (This is handled by calls to addRemoteExecParamsToParamList() from the
* functions preprocess_initplans() and ExecutorRun().)
*
* Each QE receives its assignment as a message of type 'M' in PostgresMain().
* The message is deserialized and processed by exec_mpp_query() in postgres.c.
*/
void
cdbdisp_dispatchPlan(struct QueryDesc *queryDesc,
bool planRequiresTxn,
bool cancelOnError, struct CdbDispatcherState *ds)
{
char *splan,
*sddesc,
*sparams;
int splan_len,
splan_len_uncompressed,
sddesc_len,
sparams_len;
SliceTable *sliceTbl;
int rootIdx;
int oldLocalSlice;
PlannedStmt *stmt;
bool is_SRI;
DispatchCommandQueryParms queryParms;
CdbComponentDatabaseInfo *qdinfo;
ds->primaryResults = NULL;
ds->dispatchThreads = NULL;
Assert(Gp_role == GP_ROLE_DISPATCH);
Assert(queryDesc != NULL && queryDesc->estate != NULL);
/*
* Later we'll need to operate with the slice table provided via the
* EState structure in the argument QueryDesc. Cache this information
* locally and assert our expectations about it.
*/
sliceTbl = queryDesc->estate->es_sliceTable;
rootIdx = RootSliceIndex(queryDesc->estate);
Assert(sliceTbl != NULL);
Assert(rootIdx == 0 ||
(rootIdx > sliceTbl->nMotions
&& rootIdx <= sliceTbl->nMotions + sliceTbl->nInitPlans));
/*
* Keep old value so we can restore it. We use this field as a parameter.
*/
oldLocalSlice = sliceTbl->localSlice;
/*
* This function is called only for planned statements.
*/
stmt = queryDesc->plannedstmt;
Assert(stmt);
/*
* Let's evaluate STABLE functions now, so we get consistent values on the QEs
*
* Also, if this is a single-row INSERT statement, let's evaluate
* nextval() and currval() now, so that we get the QD's values, and a
* consistent value for everyone
*
*/
is_SRI = false;
if (queryDesc->operation == CMD_INSERT)
{
Assert(stmt->commandType == CMD_INSERT);
/*
* We might look for constant input relation (instead of SRI), but I'm afraid
* * that wouldn't scale.
*/
is_SRI = IsA(stmt->planTree, Result)
&& stmt->planTree->lefttree == NULL;
}
if (!is_SRI)
clear_relsize_cache();
if (queryDesc->operation == CMD_INSERT ||
queryDesc->operation == CMD_SELECT ||
queryDesc->operation == CMD_UPDATE ||
queryDesc->operation == CMD_DELETE)
{
MemoryContext oldContext;
oldContext = CurrentMemoryContext;
if (stmt->qdContext)
{
oldContext = MemoryContextSwitchTo(stmt->qdContext);
}
else
/*
* memory context of plan tree should not change
*/
{
MemoryContext mc = GetMemoryChunkContext(stmt->planTree);
oldContext = MemoryContextSwitchTo(mc);
}
stmt->planTree = (Plan *) exec_make_plan_constant(stmt, is_SRI);
MemoryContextSwitchTo(oldContext);
}
/*
* Cursor queries and bind/execute path queries don't run on the
* writer-gang QEs; but they require snapshot-synchronization to
* get started.
*
* initPlans, and other work (see the function pre-evaluation
* above) may advance the snapshot "segmateSync" value, so we're
* best off setting the shared-snapshot-ready value here. This
* will dispatch to the writer gang and force it to set its
* snapshot; we'll then be able to serialize the same snapshot
* version (see qdSerializeDtxContextInfo() below).
*/
if (queryDesc->extended_query)
{
verify_shared_snapshot_ready();
}
/*
* serialized plan tree. Note that we're called for a single
* slice tree (corresponding to an initPlan or the main plan), so the
* parameters are fixed and we can include them in the prefix.
*/
splan = serializeNode((Node *) queryDesc->plannedstmt,
&splan_len, &splan_len_uncompressed);
uint64 plan_size_in_kb = ((uint64) splan_len_uncompressed) / (uint64) 1024;
if (0 < gp_max_plan_size && plan_size_in_kb > gp_max_plan_size)
{
ereport(ERROR,
(errcode(ERRCODE_STATEMENT_TOO_COMPLEX),
(errmsg("Query plan size limit exceeded, current size: "
UINT64_FORMAT "KB, max allowed size: %dKB",
plan_size_in_kb, gp_max_plan_size),
errhint("Size controlled by gp_max_plan_size"))));
}
Assert(splan != NULL && splan_len > 0 && splan_len_uncompressed > 0);
if (queryDesc->params != NULL && queryDesc->params->numParams > 0)
{
ParamListInfoData *pli;
ParamExternData *pxd;
StringInfoData parambuf;
Size length;
int plioff;
int32 iparam;
/*
* Allocate buffer for params
*/
initStringInfo(¶mbuf);
/*
* Copy ParamListInfoData header and ParamExternData array
*/
pli = queryDesc->params;
length = (char *) &pli->params[pli->numParams] - (char *) pli;
plioff = parambuf.len;
Assert(plioff == MAXALIGN(plioff));
appendBinaryStringInfo(¶mbuf, pli, length);
/*
* Copy pass-by-reference param values.
*/
for (iparam = 0; iparam < queryDesc->params->numParams; iparam++)
{
int16 typlen;
bool typbyval;
/*
* Recompute pli each time in case parambuf.data is repalloc'ed
*/
pli = (ParamListInfoData *) (parambuf.data + plioff);
pxd = &pli->params[iparam];
if (pxd->ptype == InvalidOid)
continue;
/*
* Does pxd->value contain the value itself, or a pointer?
*/
get_typlenbyval(pxd->ptype, &typlen, &typbyval);
if (!typbyval)
{
char *s = DatumGetPointer(pxd->value);
if (pxd->isnull || !PointerIsValid(s))
{
pxd->isnull = true;
pxd->value = 0;
}
else
{
length = datumGetSize(pxd->value, typbyval, typlen);
/*
* We *must* set this before we
* append. Appending may realloc, which will
* invalidate our pxd ptr. (obviously we could
* append first if we recalculate pxd from the new
* base address)
*/
pxd->value = Int32GetDatum(length);
appendBinaryStringInfo(¶mbuf, &iparam, sizeof(iparam));
appendBinaryStringInfo(¶mbuf, s, length);
}
}
}
sparams = parambuf.data;
sparams_len = parambuf.len;
}
else
{
sparams = NULL;
sparams_len = 0;
}
sddesc = serializeNode((Node *) queryDesc->ddesc, &sddesc_len, NULL /*uncompressed_size */ );
MemSet(&queryParms, 0, sizeof(queryParms));
queryParms.strCommand = queryDesc->sourceText;
queryParms.serializedQuerytree = NULL;
queryParms.serializedQuerytreelen = 0;
queryParms.serializedPlantree = splan;
queryParms.serializedPlantreelen = splan_len;
queryParms.serializedParams = sparams;
queryParms.serializedParamslen = sparams_len;
queryParms.serializedQueryDispatchDesc = sddesc;
queryParms.serializedQueryDispatchDesclen = sddesc_len;
queryParms.rootIdx = rootIdx;
/*
* sequence server info
*/
qdinfo = &(getComponentDatabases()->entry_db_info[0]);
Assert(qdinfo != NULL && qdinfo->hostip != NULL);
queryParms.seqServerHost = pstrdup(qdinfo->hostip);
queryParms.seqServerHostlen = strlen(qdinfo->hostip) + 1;
queryParms.seqServerPort = seqServerCtl->seqServerPort;
/*
* serialized a version of our snapshot
*/
/*
* Generate our transction isolations. We generally want Plan
* based dispatch to be in a global transaction. The executor gets
* to decide if the special circumstances exist which allow us to
* dispatch without starting a global xact.
*/
queryParms.serializedDtxContextInfo =
qdSerializeDtxContextInfo(&queryParms.serializedDtxContextInfolen,
true /* wantSnapshot */ ,
queryDesc->extended_query,
mppTxnOptions(planRequiresTxn),
"cdbdisp_dispatchPlan");
cdbdisp_dispatchX(&queryParms, cancelOnError, sliceTbl, ds);
sliceTbl->localSlice = oldLocalSlice;
}
/*
* Function preprocess_initplans() is called from ExecutorRun running a
* parallel plan on the QD. The call happens prior to dispatch of the
* main plan, and only if there are some initplans.
*
* Argument queryDesc is the one passed in to ExecutorRun.
*
* The function loops through the estate->es_param_exec_vals array, which
* has plan->nParamExec elements. Each element is a ParamExecData struct,
* and the index of the element in the array is the paramid of the Param
* node in the Plan that corresponds to the result of the subquery.
*
* The execPlan member points to a SubPlanState struct for the
* subquery. The value and isnull members hold the result
* of executing the SubPlan.
* I think that the order of the elements in this array guarantees
* that for a subplan X within a subplan Y, X will come before Y in the array.
* If a subplan returns multiple columns (like a MULTIEXPR_SUBLINK), each will be
* a separate entry in the es_param_exec_vals array, but they will all have
* the same value for execPlan.
* In order to evaluate a subplan, we call ExecSetParamPlan.
* This is a postgres function, but has been modified from its original form
* to parallelize subplans. Inside ExecSetParamPlan, the
* datum result(s) of the subplan are stuffed into the value field
* of the ParamExecData struct(s). It finds the proper one based on the
* setParam list in the SubPlan node.
* In order to handle SubPlans of SubPlans, we pass in the values of the
* estate->es_param_exec_vals as ParamListInfo structs to the ExecSetParamPlan call.
* These are then serialized into the mppexec all as parameters. In this manner, the
* result of a SubPlan of a SubPlan is available.
*/
void
preprocess_initplans(QueryDesc *queryDesc)
{
ParamListInfo originalPli,
augmentedPli;
int i;
// Plan *plan = queryDesc->plantree;
EState *estate = queryDesc->estate;
int originalRoot,
originalSlice,
rootIndex;
if (queryDesc->plannedstmt->nCrossLevelParams == 0)
return;
originalPli = queryDesc->params;
originalRoot = RootSliceIndex(queryDesc->estate);
originalSlice = LocallyExecutingSliceIndex(queryDesc->estate);
Assert(originalSlice == 0); /* Original slice being executed is slice 0 */
/*
* Loop through the estate->es_param_exec_vals. This array has an element
* for each PARAM_EXEC (internal) param, and a pointer to the SubPlanState
* to execute to evaluate it. It seems that they are created in the proper
* order, i.e. if a subplan x has a sublan y, then y will come before x in
* the es_param_exec_vals array.
*/
for (i = 0; i < queryDesc->plannedstmt->nCrossLevelParams; i++)
{
ParamExecData *prm;
SubPlanState *sps;
prm = &estate->es_param_exec_vals[i];
sps = (SubPlanState *) prm->execPlan;
/*
* Append all the es_param_exec_vals datum values on to the external
* parameter list so they can be serialized in the mppexec call to the
* QEs. Do this inside the loop since later initplans may depend on
* the results of earlier ones.
*
* TODO Some of the work of addRemoteExecParamsToParmList could be
* factored out of the loop.
*/
augmentedPli = addRemoteExecParamsToParamList(queryDesc->plannedstmt,
originalPli,
estate->es_param_exec_vals);
if (sps != NULL)
{
SubPlan *subplan = (SubPlan *)sps->xprstate.expr;
Assert(IsA(subplan, SubPlan) &&
subplan->qDispSliceId > 0);
sps->planstate->plan->nParamExec = queryDesc->plannedstmt->nCrossLevelParams;
sps->planstate->plan->nMotionNodes = queryDesc->plannedstmt->nMotionNodes;
sps->planstate->plan->dispatch = DISPATCH_PARALLEL;
/*
* Adjust for the slice to execute on the QD.
*/
rootIndex = subplan->qDispSliceId;
queryDesc->estate->es_sliceTable->localSlice = rootIndex;
/* set our global sliceid variable for elog. */
currentSliceId = rootIndex;
/*
* This runs the SubPlan and puts the answer back into prm->value.
*/
queryDesc->params = augmentedPli;
/*
* Use ExprContext to set the param. If ExprContext is not initialized,
* create a new one here. (see MPP-3511)
*/
if (sps->planstate->ps_ExprContext == NULL)
sps->planstate->ps_ExprContext = CreateExprContext(estate);
/* MPP-12048: Set the right slice index before execution. */
Assert( (subplan->qDispSliceId > queryDesc->plannedstmt->nMotionNodes) &&
(subplan->qDispSliceId <=
(queryDesc->plannedstmt->nMotionNodes
+ queryDesc->plannedstmt->nInitPlans) ) );
Assert(LocallyExecutingSliceIndex(sps->planstate->state) == subplan->qDispSliceId);
//sps->planstate->state->es_cur_slice_idx = subplan->qDispSliceId;
ExecSetParamPlan(sps, sps->planstate->ps_ExprContext, queryDesc);
/*
* We dispatched, and have returned. We may have used the
* interconnect; so let's bump the interconnect-id.
*/
queryDesc->estate->es_sliceTable->ic_instance_id = ++gp_interconnect_id;
}
queryDesc->params = originalPli;
queryDesc->estate->es_sliceTable->localSlice = originalSlice;
currentSliceId = originalSlice;
pfree(augmentedPli);
}
}
