Merge recent trunk enchancements into the seekscan-improvements branch.

FossilOrigin-Name: d9e85fe80cdd3d798a583a5f99148235d0c3f39adfabbc661615893c387e6e45

diff --cc manifest
index d457afdd8a9dcbe6fdfea84638e188dfb3a87f94,a57f79dc4d46333f5b18ef6cd162edd46ad46e0b..5aab8fbf36917b25730ae1dce3d8f647c5bf4967
--- 1/manifest
--- 2/manifest
+++ b/manifest
@@@ -1,5 -1,5 +1,5 @@@
- C Add\san\soptimization\scontrol\sbit\sto\sdisable\sthe\sOP_SeekScan\soptimization.
- D 2021-06-02T19:28:07.128
 -C Fix\sa\scase\swhere\scombining\srow-value\sUPDATE\sFROM\ssyntax\swith\swindow\sfunctions\sover\saggregates\scan\scause\san\serror.
 -D 2021-06-03T18:56:42.861
++C Merge\srecent\strunk\senchancements\sinto\sthe\sseekscan-improvements\sbranch.
++D 2021-06-04T12:29:22.099
  F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
  F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
  F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@@ -616,7 -616,7 +616,7 @@@ F src/upsert.c df8f1727d62b5987c4fd302c
  F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
  F src/util.c 41c7a72da1df47864faa378a1c720b38adb288c6838cb6be5594511b6287a048
  F src/vacuum.c 492422c1463c076473bae1858799c7a0a5fe87a133d1223239447c422cd26286
- F src/vdbe.c bcb074ce72ad18723ce01d21d389dac60069270a42fb5e832dc567ccc62b6a13
 -F src/vdbe.c c42799bcd6cbeaf33a1767dde3ba926370afec4f82ba7ca92327a099251f62ec
++F src/vdbe.c a51f4947380b0561ef70730e1144bf3837216cfea61a59a498149d47eeb09943
  F src/vdbe.h 25dabb25c7e157b84e59260cfb5b466c3ac103ede9f36f4db371332c47601abe
  F src/vdbeInt.h 58980223a32495ad059d10581b83e133abdc77248b1bab85c080cab8a13bd819
  F src/vdbeapi.c d9e99daf59fec928986838b3389a7337e82fec6b3b5de30206cb99fb4661b94e
@@@ -1918,7 -1918,7 +1918,7 @@@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a9
  F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
  F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
  F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
- P a87f8ecd6db11ea40a15314b875fc78289c19ab2dec6f738b4bf37f4aafa7bbd
- R 0673ef2c1144007e5dc9919859a8d932
 -P 820ae3b117c2d8c117c0c5a4e440a7d06886772516c7fc0a84606388f91be195
 -R 3fd4ec14904b0e03c6d406344d944d84
 -U dan
 -Z f80d5b48e051c51974d8a351a0138ba6
++P f674c41e5cbbb08ffc3cc00ab449229b672054c872e209337f12e7eacb531fe5 4a587c3492faa99490fd67ca1de9fceafcdc12d220f42817791923be258b73f1
++R e31162f50a8fe0f7f09f83d8467f9ef2
 +U drh
- Z e77ba6d1357c1434f617cbb216a877e4
++Z f3a9a5e483214de7c18a55211d90eb86

diff --cc manifest.uuid
index c542abada012dc7e0922fb9ed6a2e929a15eda28,f4119a266a266ee3fd412ebdf882cae7421e4c24..9b65ccd6043dd750553af0001581c66d2456b9f7
--- 1/manifest.uuid
--- 2/manifest.uuid
+++ b/manifest.uuid
@@@ -1,1 -1,1 +1,1 @@@
- f674c41e5cbbb08ffc3cc00ab449229b672054c872e209337f12e7eacb531fe5
 -4a587c3492faa99490fd67ca1de9fceafcdc12d220f42817791923be258b73f1
++d9e85fe80cdd3d798a583a5f99148235d0c3f39adfabbc661615893c387e6e45

diff --cc src/vdbe.c
Simple merge