diff options
Diffstat (limited to 'src/include/nodes/execnodes.h')
| -rw-r--r-- | src/include/nodes/execnodes.h | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index 996efa8f87d..cb293a0be55 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.202 2009/03/21 00:04:40 tgl Exp $ + * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.203 2009/04/02 22:39:30 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -201,16 +201,25 @@ typedef struct ReturnSetInfo * * The planner very often produces tlists that consist entirely of * simple Var references (lower levels of a plan tree almost always - * look like that). So we have an optimization to handle that case - * with minimum overhead. + * look like that). And top-level tlists are often mostly Vars too. + * We therefore optimize execution of simple-Var tlist entries. + * The pi_targetlist list actually contains only the tlist entries that + * aren't simple Vars, while those that are Vars are processed using the + * varSlotOffsets/varNumbers/varOutputCols arrays. * - * targetlist target list for projection + * The lastXXXVar fields are used to optimize fetching of fields from + * input tuples: they let us do a slot_getsomeattrs() call to ensure + * that all needed attributes are extracted in one pass. + * + * targetlist target list for projection (non-Var expressions only) * exprContext expression context in which to evaluate targetlist * slot slot to place projection result in - * itemIsDone workspace for ExecProject - * isVarList TRUE if simple-Var-list optimization applies + * itemIsDone workspace array for ExecProject + * directMap true if varOutputCols[] is an identity map + * numSimpleVars number of simple Vars found in original tlist * varSlotOffsets array indicating which slot each simple Var is from - * varNumbers array indicating attr numbers of simple Vars + * varNumbers array containing input attr numbers of simple Vars + * varOutputCols array containing output attr numbers of simple Vars * lastInnerVar highest attnum from inner tuple slot (0 if none) * lastOuterVar highest attnum from outer tuple slot (0 if none) * lastScanVar highest attnum from scan tuple slot (0 if none) @@ -223,9 +232,11 @@ typedef struct ProjectionInfo ExprContext *pi_exprContext; TupleTableSlot *pi_slot; ExprDoneCond *pi_itemIsDone; - bool pi_isVarList; + bool pi_directMap; + int pi_numSimpleVars; int *pi_varSlotOffsets; int *pi_varNumbers; + int *pi_varOutputCols; int pi_lastInnerVar; int pi_lastOuterVar; int pi_lastScanVar; |