David Jones

I put out a new exec_convert kit (007). The main new feature is it better handles text in the spreadsheet that isn't 7-bit ASCII. .xlsx files store text using UTF8, which xlsxvtab virtual tables now decode and convert to the 8-bit DEC MCS character set byte default. If you want to disable the conversion, issue the SQL statement "SELECT xlsxvtab_config('text_convert', NULL);" prior to creating the virtual table (or first access if already defined in the schema). The default DECMCS mode can do some...

I did a routine update of the kit to use the latest SQLite release, 3.49.2. There is also an updated gstvtab virtual table kit (gstvtab_003.zip). The new gstvtab tracks the library modules so you can find out which module defines a symbol. It can now show you symbol attributes for object library symbols (but not shareable image library symbols).

I add kit 52 to the files area. It has an experiment MMS file for building with clang on X86 systems. It also fixes a bug in handling of filenames/directories which contain special characters (the kind which require quoting with '^'). The names tend to give the CRTL problems, and failure of a decc$translate_vms() can lead to a program crash.

The current kit is now 50 and comes with SQLite 3.47.0. The speedtest1 program runs dramatically faster with 3.47 than 3.46. They apparently tweaked the resident pages it the cache so speedtest1 makes 98% fewer I/O calls to the VFS.

I added a new incremental update to kit 48, superceding the 20240623 incremental (I'll wait until SQLite makes a new release before making a new full kit). The changes made have to do with the perf_timer VFS option: I wanted to better track how well the internal file cache was working so added statistics counters to that code. When enabled by bit 2 in the perf_timer setting, the new counters will produce a report showing: * Read/write ratio of calls to from the SQLite library to the VFS * The read...

I added a new incremental update to kit 48, superceding the 20240623 incremental (I'll wait until SQLite makes a new release before making a new full kit). The changes made have to do with the perf_timer VFS option: I wanted to better track how well the internal file cache was working so added statistics counters to that code. When enabled by bit 2 in the perf_timer setting, the new counters will produce a report showing: * Read/write ratio of calls to from the SQLite library to the VFS * The read...

I found a bug in VSI's C compiler for X86 that makes some of SQLite's builtin aggregate SQL functions not work. I made a workaround (re-implement SUM(), AVG(), TOTAL() in a auto-loaded extension built into the VMS VFS) and made it available in an 'increment' kit: vmsvfs_in20240623.zip. Note that the bug does not affect Alpha or IA64.

I found it strange that I hadn't encounter the problem with SUM before now, further investigation shows that: 1. SQLite didn't use the Kahan-Babushka algorithm until version 3.43.0, released in August 2023. 2. The cross-compiler for X86 doesn't appear to have the bug. The updated algorithm attempts to get a more accurate sum when the list of addends includes both large magnitude and small magnitude values. The problem is it depends upon strict ordering of operations which optimizing compilers would...