Support extra flags/options within scripts.

__open_relation

@@ -92,7 +92,8 @@ else
 fi
 
 # Generate tags at a path that we know wxHexEditor will look for them:
-if ! ./pg_hexedit -D "$ATTRLIST" -z -R "$MIN_BLOCK_TAGS" "$MAX_BLOCK_TAGS" "$FULLPATH" > "$FULLPATH.tags"
+# shellcheck disable=SC2086
+if ! ./pg_hexedit $EXTRAFLAGS -D "$ATTRLIST" -z -R "$MIN_BLOCK_TAGS" "$MAX_BLOCK_TAGS" "$FULLPATH" > "$FULLPATH.tags"
 then
   echo "Error encountered by pg_hexedit. Could not generate all tags."
   echo "You may still wish to run: $HEXEDITOR $FULLPATH"

hexedit.cfg

@@ -6,7 +6,9 @@
 export HEXEDITOR="../wxHexEditor/wxHexEditor"
 
 # Only blocks in the range $MIN_BLOCK_TAGS - $MAX_BLOCK_TAGS receive tags:
-# (Note that setting MIN_BLOCK_TAGS>0 will disable fallback download of files.)
+# (Note that setting MIN_BLOCK_TAGS to anything other than 0 will prevent the
+# psql remote download fallback from being used.  This is due to an
+# implementation restriction that may be lifted in the future.)
 export MIN_BLOCK_TAGS=0
 export MAX_BLOCK_TAGS=200
 
@@ -21,4 +23,24 @@ export FONTSIZE=10
 #export PGDATABASE="regression"
 #export PGUSER="postgres"
 #export PGPASSWORD="password"
+#export PGHOST=localhost
 #export PGPORT=5432
+
+# Templates for using pg_hexedit options to limit annotation overhead follow
+
+# Only emit whole-page annotations for leaf pages.
+#
+# Leaf pages are typically the great majority within nbtree, GiST, GIN, or
+# SP-GiST index relations.  This option is useful with larger indexes in cases
+# where only the root and other internal pages are of interest.
+
+#export EXTRAFLAGS="-l"
+
+# Don't emit annotations for pages where the page header LSN is before
+# argument.
+#
+# Tip: The latest checkpoint's REDO location can be a helpful generic cutoff
+# point.  Run pg_controldata to get this information.  Be sure to do so before
+# a convenience script issues its own CHECKPOINT.
+
+#export EXTRAFLAGS="-x 0/167F070"