Query planner tuning: Increase the maximum number of simultaneous solutions

to track int eh solver from 10 to 12.

FossilOrigin-Name: fe2e1dadbacbe6392ceed44fd287a2ed82189cb8055f35631d37967d9a7a5d1d

1 files changed, 10 insertions, 4 deletions

diff --git a/src/where.c b/src/where.c
index a266b51d0..9ef48fb33 100644
--- a/src/where.c
+++ b/src/where.c
@@ -5242,10 +5242,16 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
 
   pParse = pWInfo->pParse;
   nLoop = pWInfo->nLevel;
-  /* TUNING: For simple queries, only the best path is tracked.
-  ** For 2-way joins, the 5 best paths are followed.
-  ** For joins of 3 or more tables, track the 10 best paths */
-  mxChoice = (nLoop<=1) ? 1 : (nLoop==2 ? 5 : 10);
+  /* TUNING: mxChoice is the maximum number of possible paths to preserve
+  ** at each step.  Based on the number of loops in the FROM clause:
+  **
+  **     nLoop      mxChoice
+  **     -----      --------
+  **       1            1            // the most common case
+  **       2            5
+  **       3+          12
+  */
+  mxChoice = (nLoop<=1) ? 1 : (nLoop==2 ? 5 : 12);
   assert( nLoop<=pWInfo->pTabList->nSrc );
   WHERETRACE(0x002, ("---- begin solver.  (nRowEst=%d, nQueryLoop=%d)\n",
                      nRowEst, pParse->nQueryLoop));