Hold a transaction during PRAGMA optimize, for performance.

FossilOrigin-Name: d13b79eae6df7f9d1f3b8062ddc75a12ff038196b3d752d2672a9925fa45ca56

1 files changed, 7 insertions, 0 deletions

diff --git a/src/pragma.c b/src/pragma.c
index 40a31846b..9bb971ed7 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -2446,6 +2446,7 @@ void sqlite3Pragma(
     char *zSubSql;         /* SQL statement for the OP_SqlExec opcode */
     u32 opMask;            /* Mask of operations to perform */
     int nLimit;            /* Analysis limit to use */
+    int once = 0;          /* One-time initialization done */
 
 #ifndef SQLITE_DEFAULT_OPTIMIZE_LIMIT
 # define SQLITE_DEFAULT_OPTIMIZE_LIMIT 400
@@ -2488,6 +2489,12 @@ void sqlite3Pragma(
           continue;
         }
 
+        /* Hold a write transaction open for efficiency */
+        if( !once ){
+          sqlite3BeginWriteOperation(pParse, 0, iDb);
+          once = 1;
+        }
+
         /* Reanalyze if the table is 25 times larger than the last analysis */
         szThreshold = pTab->nRowLogEst;
         for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){