• Fix "separate by the OR operator" → separated, here

• Fix "term that constraints column c" → constrains later in that section.

• Fix attempts to use Markdown bold and italic formatting markup in HTML here, here, and here.

• Pluralize "have many duplicate" → "has many duplicates"

• "above in paragraph 1.0" should just be an intra-doc named anchor, pointing here

• Most uses of sentence-leading conjunctions should be comma-spliced to the prior sentence instead. There are good justifications for doing otherwise — special emphasis, summary of a long explanation, lead sentence of a new paragraph, etc. — but few of the uses here apply.

• Add comma between complete sentences in "…run 4 times and the query…"

• Recast the paragraph-trailing sentence "That approach is not recommended except for the one scenario described in the next paragraph" as the leading sentence of the next paragraph for clarity and brevity: "That approach is only recommended in a single scenario: …"

• Swap these clauses: "when a new database instance is first created the ANALYZE command is ineffective" → "the ANALYZE command is ineffective when a new database instance is first created". Otherwise, it wants a comma, which slows the reader unnecessarily.

• The use of the adverb "anyway" here is wrong: "…clause anyway it sees fit". It should be a noun phrase, "any way".

• Capitalization of headers is inconsistent, mixing sentence case and start case styles. Rather than standardize on either, proper title case is more broadly accepted. (Lowercased prepositions and conjunctions, etc.)

• Remove "and when it is unsafe": the preceding "when" qualifier already marks this as an either/or condition, so it reads more clearly without this effective repeat. You may wish to use "whether" in place of "when" to make the condition clearer.

• Duplicate caveat: "The casual reader is not expected to understand or remember any part of the list above." The paragraph before the preceding list says much the same thing. Pick one. If you want my suggestion, drop the paragraph after the list entirely; make your summary points before giving the detailed list.

• "and then use that index" → "and using that index"

• "Sometimes a LEFT JOIN can be converted into an ordinary JOIN, if there are terms" → "A LEFT JOIN can sometimes be converted into an ordinary JOIN when there are terms…" (removes a comma)

I recently posted another issue in that document in a thread in the forum, so you might want to include that in the list here:

/forumpost/b6bd0e08bc

I hadn’t seen this thread when I posted mine, otherwise I had directly replied here, sorry for the forum clutter.