Change the 0x20000 bit (use analysis limit) to 0x10, meaning that this feature

is on by default.  The default analysis limit is changed to 2000 which is
almost always sufficient for accurate analysis results.

FossilOrigin-Name: 4abd47b5917099a2f74e53e12c987da0722304a5e9a93b6d43015c1f45c48444

diff --git a/manifest b/manifest
index e3c3328eb19488b55159e4ebc0611085e7410f7e..54ba56837e05813595ca7fe682d51f36178d345f 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Hold\sa\stransaction\sduring\sPRAGMA\soptimize,\sfor\sperformance.
-D 2024-02-18T01:12:22.988
+C Change\sthe\s0x20000\sbit\s(use\sanalysis\slimit)\sto\s0x10,\smeaning\sthat\sthis\sfeature\nis\son\sby\sdefault.\s\sThe\sdefault\sanalysis\slimit\sis\schanged\sto\s2000\swhich\sis\nalmost\salways\ssufficient\sfor\saccurate\sanalysis\sresults.
+D 2024-02-19T13:06:27.586
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -732,7 +732,7 @@ F src/parse.y bfd6da46fc895cd8237400ff485d04ab0b32e47eb56de20982bb7f53e56c1f42
 F src/pcache.c 040b165f30622a21b7a9a77c6f2e4877a32fb7f22d4c7f0d2a6fa6833a156a75
 F src/pcache.h 1497ce1b823cf00094bb0cf3bac37b345937e6f910890c626b16512316d3abf5
 F src/pcache1.c 602acb23c471bb8d557a6f0083cc2be641d6cafcafa19e481eba7ef4c9ca0f00
-F src/pragma.c c7ef49d3332badd6e17ac46e0aca762d7973c1e28156bc480c47aa3e56ae4d03
+F src/pragma.c b877efa88ea41560ee5dd95daa30c8cadb743381c59b8921a5143bf0792c6e3b
 F src/pragma.h e690a356c18e98414d2e870ea791c1be1545a714ba623719deb63f7f226d8bb7
 F src/prepare.c 371f6115cb69286ebc12c6f2d7511279c2e47d9f54f475d46a554d687a3b312c
 F src/printf.c 18fbdf028345c8fbe6044f5f5bfda5a10d48d6287afef088cc21b0ca57985640
@@ -947,7 +947,7 @@ F test/boundary4.test 89e02fa66397b8a325d5eb102b5806f961f8ec4b
 F test/btree01.test fef17d9e999ac4f04095948e3438fbe674f4e07bb2c63bb1cad41d87baee077f
 F test/btree02.test 7555a5440453d900410160a52554fe6478af4faf53098f7235f1f443d5a1d6cc
 F test/btreefault.test a82a23b0578bc587afbf9a622c8f54a54f63762f062ba8a35613cfee38ab42f9
-F test/busy.test 510dc6daaad18bcbbc085bcc6217d6dc418def5e73f72ce1475eea0cb7834727
+F test/busy.test caff7164c16ce06a53af51f9e4c2753d4cc64250e00790a5e48b9c4f4be37597
 F test/busy2.test 20823a5d7c42fb257d9f108c66312d90b1bb4ec3d80ba6b4e371073727560f98
 F test/cache.test 13bc046b26210471ca6f2889aceb1ea52dc717de
 F test/cacheflush.test af25bb1509df04c1da10e38d8f322d66eceedf61
@@ -2162,8 +2162,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P dd4497062569eec9ddfdaa7d6394c83ff40a7a59c6697a161bc4ff6d8af3bb29
-R 5aca31e5331abdce830c908f0aade7ae
+P d13b79eae6df7f9d1f3b8062ddc75a12ff038196b3d752d2672a9925fa45ca56
+R e258fa6228ef566d2b5670b2822a20d1
 U drh
-Z 497aafa2ad4da05132856bc0e0f3518f
+Z e864b92d6fb5e0c6f09ca55fa83dd960
 # Remove this line to create a well-formed Fossil manifest.

diff --git a/manifest.uuid b/manifest.uuid
index 0aec312a780cdff4b900e7a6970b2fdd04eb636a..9cda73c43e934161ac4b643080466e7db235f4dc 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d13b79eae6df7f9d1f3b8062ddc75a12ff038196b3d752d2672a9925fa45ca56
\ No newline at end of file
+4abd47b5917099a2f74e53e12c987da0722304a5e9a93b6d43015c1f45c48444
\ No newline at end of file

diff --git a/src/pragma.c b/src/pragma.c
index 9bb971ed77585ecbf4ac2801c75bca787b871711..6e1fc8bc002054922931041d702322ac48a388d4 100644 (file)
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -30,6 +30,34 @@
 ** ../tool/mkpragmatab.tcl. */
 #include "pragma.h"
 
+/*
+** When the 0x10 bit of PRAGMA optimize is set, any ANALYZE commands
+** will be run with an analysis_limit set to the lessor of the value of
+** the following macro or to the actual analysis_limit if it is non-zero,
+** in order to prevent PRAGMA optimize from running for too long.
+**
+** The value of 2000 is chosen emperically so that the worst-case run-time
+** for PRAGMA optimize does not exceed 100 milliseconds against a variety
+** of test databases on a RaspberryPI-4 compiled using -Os and without
+** -DSQLITE_DEBUG.  Of course, your mileage may vary.  For the purpose of
+** his paragraph, "worst-case" means that ANALYZE ends up being
+** run on every table in the database.  The worst case typically only
+** happens if PRAGMA optimize is run on a database file for which ANALYZE
+** has not been previously run and the 0x10000 flag is included so that
+** all tables are analyzed.  The usual case for PRAGMA optimize is that
+** no ANALYZE commands will be run at all, or if any ANALYZE happens it
+** will be against a single table, so that expected timing for PRAGMA
+** optimize on a PI-4 is more like 1 millisecond or less with the 0x10000
+** flag or less than 100 microseconds without the 0x10000 flag.
+**
+** An analysis limit of 2000 is almost always sufficient for the query
+** planner to fully characterize an index.  The additional accuracy from
+** a larger analysis is not usually helpful.
+*/
+#ifndef SQLITE_DEFAULT_OPTIMIZE_LIMIT
+# define SQLITE_DEFAULT_OPTIMIZE_LIMIT 2000
+#endif
+
 /*
 ** Interpret the given string as a safety level.  Return 0 for OFF,
 ** 1 for ON or NORMAL, 2 for FULL, and 3 for EXTRA.  Return 1 for an empty or
@@ -2390,20 +2418,19 @@ void sqlite3Pragma(
   **    0x00002    Run ANALYZE on tables that might benefit.  On by default.
   **               See below for additional information.
   **
+  **    0x00010    Run all ANALYZE operations using an analysis_limit that
+  **               is the lessor of the current analysis_limit and the
+  **               SQLITE_DEFAULT_OPTIMIZE_LIMIT compile-time option.
+  **               The default value of SQLITE_DEFAULT_OPTIMIZE_LIMIT is
+  **               currently (2024-02-19) set to 2000, which is such that
+  **               the worst case run-time for PRAGMA optimize on a 100MB
+  **               database will usually be less than 100 milliseconds on
+  **               a RaspberryPI-4 class machine.  Off by default.
+  **
   **    0x10000    Look at tables to see if they need to be reanalyzed
   **               even if they have not been queried during the current
   **               connection.  Off by default.
   **
-  **    0x20000    Run all ANALYZE operations using an analysis_limit that
-  **               is the lessor of the current analysis_limit and the
-  **               SQLITE_DEFAULT_OPTIMIZE_LIMIT compile-time option,
-  **               nominally 400.  Off by default.
-  **
-  **    0x40000    Tables become candidates for reanalysis if their size
-  **               grows or shrinks by 10x.  Without this option, they
-  **               become candidates for reanalysis if their size grows
-  **               or shrinks by 25x.  Off (25x mode) by default.
-  **
   ** The default MASK is and always shall be 0x0fffe.  In the current
   ** implementation, the default mask only covers the 0x00002 optimization,
   ** though additional optimizations that are covered by 0x0fffe might be
@@ -2422,9 +2449,9 @@ void sqlite3Pragma(
   **     at some point during the lifetime of the current connection.
   **
   ** (3) One or more indexes of the table are currently unanalyzed OR
-  **     the number of rows in the table has increased or decreased
-  **     25 times or more (10 times or more if the 0x40000 bit is set)
-  **     since the last time ANALYZE was run.
+  **     the number of rows in the table has increased or decreased by
+  **     10-fold (the new size is either greater than 10 times the old
+  **     size or less than 1/10th of the old size).
   **
   ** (4) The table is an ordinary table, not a virtual table or view.
   **
@@ -2448,17 +2475,13 @@ void sqlite3Pragma(
     int nLimit;            /* Analysis limit to use */
     int once = 0;          /* One-time initialization done */
 
-#ifndef SQLITE_DEFAULT_OPTIMIZE_LIMIT
-# define SQLITE_DEFAULT_OPTIMIZE_LIMIT 400
-#endif
-
     if( zRight ){
       opMask = (u32)sqlite3Atoi(zRight);
       if( (opMask & 0x02)==0 ) break;
     }else{
       opMask = 0xfffe;
     }
-    if( (opMask & 0x20000)==0 ){
+    if( (opMask & 0x10)==0 ){
       nLimit = 0;
     }else if( db->nAnalysisLimit>0
            && db->nAnalysisLimit<SQLITE_DEFAULT_OPTIMIZE_LIMIT ){
@@ -2490,12 +2513,13 @@ void sqlite3Pragma(
         }
 
         /* Hold a write transaction open for efficiency */
-        if( !once ){
+        if( !once || 1 ){
           sqlite3BeginWriteOperation(pParse, 0, iDb);
           once = 1;
         }
 
-        /* Reanalyze if the table is 25 times larger than the last analysis */
+        /* Reanalyze if the table is 10 times larger or smaller than
+        ** the last analysis */
         szThreshold = pTab->nRowLogEst;
         for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
           if( !pIdx->hasStat1 ){
@@ -2504,7 +2528,7 @@ void sqlite3Pragma(
           }
         }
         if( szThreshold>=0 ){
-          LogEst iRange = (opMask & 0x40000) ? 33 : 46;
+          LogEst iRange = 33;   /* 10x size change */
           sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
           sqlite3VdbeAddOp4Int(v, OP_IfSizeBetween, iTabCur,
                          sqlite3VdbeCurrentAddr(v)+3+(opMask&1),

diff --git a/test/busy.test b/test/busy.test
index be0515b013072ec3b50a2f99bfd7097ef623dab4..896c7fa651e44eeb0c180d1afbc47c25c744f290 100644 (file)
--- a/test/busy.test
+++ b/test/busy.test
@@ -106,7 +106,7 @@ do_test 3.4 {
 proc busy_handler {n} { return 1 }
 do_test 3.5 {
   catchsql { PRAGMA optimize }
-} {0 {}}
+} {1 {database is locked}}
 
 do_test 3.6 {
   execsql { COMMIT } db2