diff options
| -rw-r--r-- | doc/src/sgml/custom-scan.sgml | 13 | ||||
| -rw-r--r-- | src/backend/executor/execAmi.c | 17 | ||||
| -rw-r--r-- | src/backend/optimizer/plan/createplan.c | 8 | ||||
| -rw-r--r-- | src/include/nodes/extensible.h | 4 |
4 files changed, 26 insertions, 16 deletions
diff --git a/doc/src/sgml/custom-scan.sgml b/doc/src/sgml/custom-scan.sgml index 239ba29de72..93d96f2f566 100644 --- a/doc/src/sgml/custom-scan.sgml +++ b/doc/src/sgml/custom-scan.sgml @@ -71,10 +71,17 @@ typedef struct CustomPath <para> <structfield>path</structfield> must be initialized as for any other path, including the row-count estimate, start and total cost, and sort ordering provided - by this path. <structfield>flags</structfield> is a bit mask, which should include + by this path. <structfield>flags</structfield> is a bit mask, which + specifies whether the scan provider can support certain optional + capabilities. <structfield>flags</structfield> should include <literal>CUSTOMPATH_SUPPORT_BACKWARD_SCAN</literal> if the custom path can support - a backward scan and <literal>CUSTOMPATH_SUPPORT_MARK_RESTORE</literal> if it - can support mark and restore. Both capabilities are optional. + a backward scan, <literal>CUSTOMPATH_SUPPORT_MARK_RESTORE</literal> if it + can support mark and restore, + and <literal>CUSTOMPATH_SUPPORT_PROJECTION</literal> if it can perform + projections. (If <literal>CUSTOMPATH_SUPPORT_PROJECTION</literal> is not + set, the scan node will only be asked to produce Vars of the scanned + relation; while if that flag is set, the scan node must be able to + evaluate scalar expressions over these Vars.) An optional <structfield>custom_paths</structfield> is a list of <structname>Path</structname> nodes used by this custom-path node; these will be transformed into <structname>Plan</structname> nodes by planner. diff --git a/src/backend/executor/execAmi.c b/src/backend/executor/execAmi.c index 10f0b349b58..522b1c20863 100644 --- a/src/backend/executor/execAmi.c +++ b/src/backend/executor/execAmi.c @@ -438,13 +438,10 @@ ExecSupportsMarkRestore(Path *pathnode) return true; case T_CustomScan: - { - CustomPath *customPath = castNode(CustomPath, pathnode); + if (castNode(CustomPath, pathnode)->flags & CUSTOMPATH_SUPPORT_MARK_RESTORE) + return true; + return false; - if (customPath->flags & CUSTOMPATH_SUPPORT_MARK_RESTORE) - return true; - return false; - } case T_Result: /* @@ -567,12 +564,8 @@ ExecSupportsBackwardScan(Plan *node) return ExecSupportsBackwardScan(((SubqueryScan *) node)->subplan); case T_CustomScan: - { - uint32 flags = ((CustomScan *) node)->flags; - - if (flags & CUSTOMPATH_SUPPORT_BACKWARD_SCAN) - return true; - } + if (((CustomScan *) node)->flags & CUSTOMPATH_SUPPORT_BACKWARD_SCAN) + return true; return false; case T_SeqScan: diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 439e6b6426c..c13da7a879f 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -7046,6 +7046,10 @@ is_projection_capable_path(Path *path) case T_MergeAppend: case T_RecursiveUnion: return false; + case T_CustomScan: + if (castNode(CustomPath, path)->flags & CUSTOMPATH_SUPPORT_PROJECTION) + return true; + return false; case T_Append: /* @@ -7092,6 +7096,10 @@ is_projection_capable_plan(Plan *plan) case T_MergeAppend: case T_RecursiveUnion: return false; + case T_CustomScan: + if (((CustomScan *) plan)->flags & CUSTOMPATH_SUPPORT_PROJECTION) + return true; + return false; case T_ProjectSet: /* diff --git a/src/include/nodes/extensible.h b/src/include/nodes/extensible.h index 9e425e56518..cc9b7e9928d 100644 --- a/src/include/nodes/extensible.h +++ b/src/include/nodes/extensible.h @@ -76,10 +76,12 @@ extern const ExtensibleNodeMethods *GetExtensibleNodeMethods(const char *name, /* * Flags for custom paths, indicating what capabilities the resulting scan - * will have. + * will have. The flags fields of CustomPath and CustomScan nodes are + * bitmasks of these flags. */ #define CUSTOMPATH_SUPPORT_BACKWARD_SCAN 0x0001 #define CUSTOMPATH_SUPPORT_MARK_RESTORE 0x0002 +#define CUSTOMPATH_SUPPORT_PROJECTION 0x0004 /* * Custom path methods. Mostly, we just need to know how to convert a |