xref: /netbsd-src/external/public-domain/sqlite/man/SQLITE_SCANSTAT_NLOOP.3 (revision 7330f729ccf0bd976a06f95fad452fe774fc7fd1)
1.Dd December 19, 2018
2.Dt SQLITE_SCANSTAT_NLOOP 3
3.Os
4.Sh NAME
5.Nm SQLITE_SCANSTAT_NLOOP ,
6.Nm SQLITE_SCANSTAT_NVISIT ,
7.Nm SQLITE_SCANSTAT_EST ,
8.Nm SQLITE_SCANSTAT_NAME ,
9.Nm SQLITE_SCANSTAT_EXPLAIN ,
10.Nm SQLITE_SCANSTAT_SELECTID
11.Nd Prepared Statement Scan Status Opcodes
12.Sh SYNOPSIS
13.Fd #define SQLITE_SCANSTAT_NLOOP
14.Fd #define SQLITE_SCANSTAT_NVISIT
15.Fd #define SQLITE_SCANSTAT_EST
16.Fd #define SQLITE_SCANSTAT_NAME
17.Fd #define SQLITE_SCANSTAT_EXPLAIN
18.Fd #define SQLITE_SCANSTAT_SELECTID
19.Sh DESCRIPTION
20The following constants can be used for the T parameter to the sqlite3_stmt_scanstatus(S,X,T,V)
21interface.
22Each constant designates a different metric for sqlite3_stmt_scanstatus()
23to return.
24.Pp
25When the value returned to V is a string, space to hold that string
26is managed by the prepared statement S and will be automatically freed
27when S is finalized.
28.Bl -tag -width Ds
29.It SQLITE_SCANSTAT_NLOOP
30The sqlite3_int64 variable pointed to by the T parameter
31will be set to the total number of times that the X-th loop has run.
32.It SQLITE_SCANSTAT_NVISIT
33The sqlite3_int64 variable pointed to by the T parameter
34will be set to the total number of rows examined by all iterations
35of the X-th loop.
36.It SQLITE_SCANSTAT_EST
37The "double" variable pointed to by the T parameter will be set to
38the query planner's estimate for the average number of rows output
39from each iteration of the X-th loop.
40If the query planner's estimates was accurate, then this value will
41approximate the quotient NVISIT/NLOOP and the product of this value
42for all prior loops with the same SELECTID will be the NLOOP value
43for the current loop.
44.It SQLITE_SCANSTAT_NAME
45The "const char *" variable pointed to by the T parameter will be set
46to a zero-terminated UTF-8 string containing the name of the index
47or table used for the X-th loop.
48.It SQLITE_SCANSTAT_EXPLAIN
49The "const char *" variable pointed to by the T parameter will be set
50to a zero-terminated UTF-8 string containing the EXPLAIN QUERY PLAN
51description for the X-th loop.
52.It SQLITE_SCANSTAT_SELECT
53The "int" variable pointed to by the T parameter will be set to the
54"select-id" for the X-th loop.
55The select-id identifies which query or subquery the loop is part of.
56The main query has a select-id of zero.
57The select-id is the same value as is output in the first column of
58an EXPLAIN QUERY PLAN query.
59.El
60.Pp
61.Sh SEE ALSO
62.Xr sqlite_int64 3
63