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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2021-07-06 18:10:11 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2021-07-06 18:10:20 -0400 |
| commit | 955b3e0f9269639fb916cee3dea37aee50b82df0 (patch) | |
| tree | 395cf4010f26d0e3f2383f9ad724cb683135acce /src | |
| parent | 5798ca529935698ab976780565fb2b4d8d34d810 (diff) | |
| download | postgresql-955b3e0f9269639fb916cee3dea37aee50b82df0.tar.gz postgresql-955b3e0f9269639fb916cee3dea37aee50b82df0.zip | |
Allow CustomScan providers to say whether they support projections.
Previously, all CustomScan providers had to support projections,
but there may be cases where this is inconvenient. Add a flag
bit to say if it's supported.
Important item for the release notes: this is non-backwards-compatible
since the default is now to assume that CustomScan providers can't
project, instead of assuming that they can. It's fail-soft, but could
result in visible performance penalties due to adding unnecessary
Result nodes.
Sven Klemm, reviewed by Aleksander Alekseev; some cosmetic fiddling
by me.
Discussion: https://postgr.es/m/CAMCrgp1kyakOz6c8aKhNDJXjhQ1dEjEnp+6KNT3KxPrjNtsrDg@mail.gmail.com
Diffstat (limited to 'src')
| -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 |
3 files changed, 16 insertions, 13 deletions
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 |