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tsmapi.h
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1 /*-------------------------------------------------------------------------
2  *
3  * tsmapi.h
4  * API for tablesample methods
5  *
6  * Copyright (c) 2015-2017, PostgreSQL Global Development Group
7  *
8  * src/include/access/tsmapi.h
9  *
10  *-------------------------------------------------------------------------
11  */
12 #ifndef TSMAPI_H
13 #define TSMAPI_H
14 
15 #include "nodes/execnodes.h"
16 #include "nodes/relation.h"
17 
18 
19 /*
20  * Callback function signatures --- see tablesample-method.sgml for more info.
21  */
22 
24  RelOptInfo *baserel,
25  List *paramexprs,
26  BlockNumber *pages,
27  double *tuples);
28 
30  int eflags);
31 
33  Datum *params,
34  int nparams,
35  uint32 seed);
36 
38 
40  BlockNumber blockno,
41  OffsetNumber maxoffset);
42 
43 typedef void (*EndSampleScan_function) (SampleScanState *node);
44 
45 /*
46  * TsmRoutine is the struct returned by a tablesample method's handler
47  * function. It provides pointers to the callback functions needed by the
48  * planner and executor, as well as additional information about the method.
49  *
50  * More function pointers are likely to be added in the future.
51  * Therefore it's recommended that the handler initialize the struct with
52  * makeNode(TsmRoutine) so that all fields are set to NULL. This will
53  * ensure that no fields are accidentally left undefined.
54  */
55 typedef struct TsmRoutine
56 {
58 
59  /* List of datatype OIDs for the arguments of the TABLESAMPLE clause */
61 
62  /* Can method produce repeatable samples across, or even within, queries? */
65 
66  /* Functions for planning a SampleScan on a physical table */
68 
69  /* Functions for executing a SampleScan on a physical table */
75 } TsmRoutine;
76 
77 
78 /* Functions in access/tablesample/tablesample.c */
79 extern TsmRoutine *GetTsmRoutine(Oid tsmhandler);
80 
81 #endif /* TSMAPI_H */
InitSampleScan_function InitSampleScan
Definition: tsmapi.h:70
bool repeatable_across_queries
Definition: tsmapi.h:63
void(* EndSampleScan_function)(SampleScanState *node)
Definition: tsmapi.h:43
OffsetNumber(* NextSampleTuple_function)(SampleScanState *node, BlockNumber blockno, OffsetNumber maxoffset)
Definition: tsmapi.h:39
struct TsmRoutine TsmRoutine
uint32 BlockNumber
Definition: block.h:31
unsigned int Oid
Definition: postgres_ext.h:31
NodeTag
Definition: nodes.h:26
void(* InitSampleScan_function)(SampleScanState *node, int eflags)
Definition: tsmapi.h:29
uint16 OffsetNumber
Definition: off.h:24
NextSampleTuple_function NextSampleTuple
Definition: tsmapi.h:73
BlockNumber(* NextSampleBlock_function)(SampleScanState *node)
Definition: tsmapi.h:37
unsigned int uint32
Definition: c.h:306
NextSampleBlock_function NextSampleBlock
Definition: tsmapi.h:72
SampleScanGetSampleSize_function SampleScanGetSampleSize
Definition: tsmapi.h:67
uintptr_t Datum
Definition: postgres.h:372
void(* BeginSampleScan_function)(SampleScanState *node, Datum *params, int nparams, uint32 seed)
Definition: tsmapi.h:32
BeginSampleScan_function BeginSampleScan
Definition: tsmapi.h:71
bool repeatable_across_scans
Definition: tsmapi.h:64
NodeTag type
Definition: tsmapi.h:57
List * parameterTypes
Definition: tsmapi.h:60
void(* SampleScanGetSampleSize_function)(PlannerInfo *root, RelOptInfo *baserel, List *paramexprs, BlockNumber *pages, double *tuples)
Definition: tsmapi.h:23
EndSampleScan_function EndSampleScan
Definition: tsmapi.h:74
Definition: pg_list.h:45
TsmRoutine * GetTsmRoutine(Oid tsmhandler)
Definition: tablesample.c:27