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diff --git a/www/c3ref/c_scanstat_est.html b/www/c3ref/c_scanstat_est.html new file mode 100644 index 0000000..77de6a1 --- /dev/null +++ b/www/c3ref/c_scanstat_est.html @@ -0,0 +1,204 @@ +<!DOCTYPE html> +<html><head> +<meta name="viewport" content="width=device-width, initial-scale=1.0"> +<meta http-equiv="content-type" content="text/html; charset=UTF-8"> +<link href="../sqlite.css" rel="stylesheet"> +<title>Prepared Statement Scan Status Opcodes</title> +<!-- path=../ --> +</head> +<body> +<div class=nosearch> +<a href="../index.html"> +<img class="logo" src="../images/sqlite370_banner.gif" alt="SQLite" border="0"> +</a> +<div><!-- IE hack to prevent disappearing logo --></div> +<div class="tagline desktoponly"> +Small. Fast. 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Each constant designates a +different metric for sqlite3_stmt_scanstatus() to return.</p> + +<p>When the value returned to V is a string, space to hold that string is +managed by the prepared statement S and will be automatically freed when +S is finalized.</p> + +<p>Not all values are available for all query elements. When a value is +not available, the output variable is set to -1 if the value is numeric, +or to NULL if it is a string (SQLITE_SCANSTAT_NAME).</p> + +<p><dl> +<a name="sqlitescanstatnloop"></a> + <dt>SQLITE_SCANSTAT_NLOOP</dt> +<dd>The <a href="../c3ref/int64.html">sqlite3_int64</a> variable pointed to by the V parameter will be +set to the total number of times that the X-th loop has run.</dd></p> + +<p><a name="sqlitescanstatnvisit"></a> + <dt>SQLITE_SCANSTAT_NVISIT</dt> +<dd>The <a href="../c3ref/int64.html">sqlite3_int64</a> variable pointed to by the V parameter will be set +to the total number of rows examined by all iterations of the X-th loop.</dd></p> + +<p><a name="sqlitescanstatest"></a> + <dt>SQLITE_SCANSTAT_EST</dt> +<dd>The "double" variable pointed to by the V parameter will be set to the +query planner's estimate for the average number of rows output from each +iteration of the X-th loop. If the query planner's estimates was accurate, +then this value will approximate the quotient NVISIT/NLOOP and the +product of this value for all prior loops with the same SELECTID will +be the NLOOP value for the current loop.</p> + +<p><a name="sqlitescanstatname"></a> + <dt>SQLITE_SCANSTAT_NAME</dt> +<dd>The "const char *" variable pointed to by the V parameter will be set +to a zero-terminated UTF-8 string containing the name of the index or table +used for the X-th loop.</p> + +<p><a name="sqlitescanstatexplain"></a> + <dt>SQLITE_SCANSTAT_EXPLAIN</dt> +<dd>The "const char *" variable pointed to by the V parameter will be set +to a zero-terminated UTF-8 string containing the <a href="../eqp.html">EXPLAIN QUERY PLAN</a> +description for the X-th loop.</p> + +<p><a name="sqlitescanstatselectid"></a> + <dt>SQLITE_SCANSTAT_SELECTID</dt> +<dd>The "int" variable pointed to by the V parameter will be set to the +id for the X-th query plan element. The id value is unique within the +statement. The select-id is the same value as is output in the first +column of an <a href="../eqp.html">EXPLAIN QUERY PLAN</a> query.</p> + +<p><a name="sqlitescanstatparentid"></a> + <dt>SQLITE_SCANSTAT_PARENTID</dt> +<dd>The "int" variable pointed to by the V parameter will be set to the +the id of the parent of the current query element, if applicable, or +to zero if the query element has no parent. This is the same value as +returned in the second column of an <a href="../eqp.html">EXPLAIN QUERY PLAN</a> query.</p> + +<p><a name="sqlitescanstatncycle"></a> + <dt>SQLITE_SCANSTAT_NCYCLE</dt> +<dd>The sqlite3_int64 output value is set to the number of cycles, +according to the processor time-stamp counter, that elapsed while the +query element was being processed. This value is not available for +all query elements - if it is unavailable the output variable is +set to -1. +</dl> +</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> + |