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<!-- keywords: sqlite3_stmt_scanstatus sqlite3_stmt_scanstatus_v2 -->
<div class=nosearch>
<a href="../c3ref/intro.html"><h2>SQLite C Interface</h2></a>
<h2>Prepared Statement Scan Status</h2>
</div>
<blockquote><pre>
int sqlite3_stmt_scanstatus(
  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
  int idx,                  /* Index of loop to report on */
  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
  void *pOut                /* Result written here */
);
int sqlite3_stmt_scanstatus_v2(
  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
  int idx,                  /* Index of loop to report on */
  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
  int flags,                /* Mask of flags defined below */
  void *pOut                /* Result written here */
);
</pre></blockquote>
<p>
These interfaces return information about the predicted and measured
performance for pStmt.  Advanced applications can use this
interface to compare the predicted and the measured performance and
issue warnings and/or rerun <a href="../lang_analyze.html">ANALYZE</a> if discrepancies are found.</p>

<p>Since this interface is expected to be rarely used, it is only
available if SQLite is compiled using the <a href="../compile.html#enable_stmt_scanstatus">SQLITE_ENABLE_STMT_SCANSTATUS</a>
compile-time option.</p>

<p>The "iScanStatusOp" parameter determines which status information to return.
The "iScanStatusOp" must be one of the <a href="../c3ref/c_scanstat_est.html">scanstatus options</a> or the behavior
of this interface is undefined. The requested measurement is written into
a variable pointed to by the "pOut" parameter.</p>

<p>The "flags" parameter must be passed a mask of flags. At present only
one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
is specified, then status information is available for all elements
of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
the EXPLAIN QUERY PLAN output) are available. Invoking API
sqlite3_stmt_scanstatus() is equivalent to calling
sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.</p>

<p>Parameter "idx" identifies the specific query element to retrieve statistics
for. Query elements are numbered starting from zero. A value of -1 may be
to query for statistics regarding the entire query. If idx is out of range
- less than -1 or greater than or equal to the total number of query
elements used to implement the statement - a non-zero value is returned and
the variable that pOut points to is unchanged.</p>

<p>See also: <a href="../c3ref/stmt_scanstatus_reset.html">sqlite3_stmt_scanstatus_reset()</a>
</p><p>See also lists of
  <a href="../c3ref/objlist.html">Objects</a>,
  <a href="../c3ref/constlist.html">Constants</a>, and
  <a href="../c3ref/funclist.html">Functions</a>.</p>