diff options
Diffstat (limited to 'src/include/nodes/plannodes.h')
| -rw-r--r-- | src/include/nodes/plannodes.h | 68 |
1 files changed, 65 insertions, 3 deletions
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h index 10177f3d7f..e9c994e4f2 100644 --- a/src/include/nodes/plannodes.h +++ b/src/include/nodes/plannodes.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/plannodes.h,v 1.112 2009/10/12 18:10:51 tgl Exp $ + * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.113 2009/10/26 02:26:42 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -59,7 +59,7 @@ typedef struct PlannedStmt Bitmapset *rewindPlanIDs; /* indices of subplans that require REWIND */ - List *rowMarks; /* a list of RowMarkClause's */ + List *rowMarks; /* a list of PlanRowMark's */ List *relationOids; /* OIDs of relations the plan depends on */ @@ -167,6 +167,8 @@ typedef struct ModifyTable List *resultRelations; /* integer list of RT indexes */ List *plans; /* plan(s) producing source data */ List *returningLists; /* per-target-table RETURNING tlists */ + List *rowMarks; /* PlanRowMarks (non-locking only) */ + int epqParam; /* ID of Param for EvalPlanQual re-eval */ } ModifyTable; /* ---------------- @@ -620,12 +622,15 @@ typedef struct SetOp * * rowMarks identifies the rels to be locked by this node; it should be * a subset of the rowMarks listed in the top-level PlannedStmt. + * epqParam is a Param that all scan nodes below this one must depend on. + * It is used to force re-evaluation of the plan during EvalPlanQual. * ---------------- */ typedef struct LockRows { Plan plan; - List *rowMarks; /* a list of RowMarkClause's */ + List *rowMarks; /* a list of PlanRowMark's */ + int epqParam; /* ID of Param for EvalPlanQual re-eval */ } LockRows; /* ---------------- @@ -644,6 +649,63 @@ typedef struct Limit /* + * RowMarkType - + * enums for types of row-marking operations + * + * When doing UPDATE, DELETE, or SELECT FOR UPDATE/SHARE, we have to uniquely + * identify all the source rows, not only those from the target relations, so + * that we can perform EvalPlanQual rechecking at need. For plain tables we + * can just fetch the TID, the same as for a target relation. Otherwise (for + * example for VALUES or FUNCTION scans) we have to copy the whole row value. + * The latter is pretty inefficient but fortunately the case is not + * performance-critical in practice. + */ +typedef enum RowMarkType +{ + ROW_MARK_EXCLUSIVE, /* obtain exclusive tuple lock */ + ROW_MARK_SHARE, /* obtain shared tuple lock */ + ROW_MARK_REFERENCE, /* just fetch the TID */ + ROW_MARK_COPY /* physically copy the row value */ +} RowMarkType; + +#define RowMarkRequiresRowShareLock(marktype) ((marktype) <= ROW_MARK_SHARE) + +/* + * PlanRowMark - + * plan-time representation of FOR UPDATE/SHARE clauses + * + * When doing UPDATE, DELETE, or SELECT FOR UPDATE/SHARE, we create a separate + * PlanRowMark node for each non-target relation in the query. Relations that + * are not specified as FOR UPDATE/SHARE are marked ROW_MARK_REFERENCE (if + * real tables) or ROW_MARK_COPY (if not). + * + * Initially all PlanRowMarks have rti == prti and isParent == false. + * When the planner discovers that a relation is the root of an inheritance + * tree, it sets isParent true, and adds an additional PlanRowMark to the + * list for each child relation (including the target rel itself in its role + * as a child). The child entries have rti == child rel's RT index and + * prti == parent's RT index, and can therefore be recognized as children by + * the fact that prti != rti. + * + * The AttrNumbers are filled in during preprocess_targetlist. We use + * different subsets of them for plain relations, inheritance children, + * and non-table relations. + */ +typedef struct PlanRowMark +{ + NodeTag type; + Index rti; /* range table index of markable relation */ + Index prti; /* range table index of parent relation */ + RowMarkType markType; /* see enum above */ + bool noWait; /* NOWAIT option */ + bool isParent; /* true if this is a "dummy" parent entry */ + AttrNumber ctidAttNo; /* resno of ctid junk attribute, if any */ + AttrNumber toidAttNo; /* resno of tableoid junk attribute, if any */ + AttrNumber wholeAttNo; /* resno of whole-row junk attribute, if any */ +} PlanRowMark; + + +/* * Plan invalidation info * * We track the objects on which a PlannedStmt depends in two ways: |