“Richard Rodgers is the most performed composer of all time — and I include Mozart and Beethoven.”

So decreed the veteran disc jockey and provocateur Jonathan Schwartz, even if Rodgers might not have taken it as the greatest of compliments. This week, the Ken Peplowski-Bucky Pizzarelli Quintet (at Dizzy’s Club Coca-Cola) and Andrea Marcovicci (at the Oak Room) are simultaneously bolstering Mr. Schwartz’s heady claim.

The proliferation of the Rodgers canon in all manner of musical forms is not something the composer himself, who could rarely see beyond the Broadway stage and the classic musical-comedy style, would have necessarily endorsed. No jazz fan he, the swinging treatment of Rodgers’s songs delivered by the clarinetist Ken Peplowski and the guitarist Bucky Pizzarelli would not have thrilled him the way it did the packed crowd for the late set at Dizzy’s on Tuesday night. (The quintet is featuring the Cole Porter Songbook on the early shows.) Would Rodgers have dug it, for instance, when Mr. Peplowski reconfigured the rhythmic emphasis of the key phrase on “Blue Room” to rush and therefore stress the two notes that hold the song title, and then take his time on the rest of the line?

Likewise, I’m glad I didn’t have to witness Rodgers’s reaction to Mr. Peplowski’s explosively swinging treatment of “Lover.” The group kept it in 3 /4 time, as Rodgers and his collaborator, Lorenz Hart, wrote it, but played it in such a fast, exciting gallop that it could hardly be called a waltz. It was also a gas to hear Mr. Pizzarelli, who is the all-time master at pushing a combo in an unstoppable 4 /4 swing groove, show that he is no less powerful in a fast three. For a climax, Messrs. Peplowski and Pizzarelli pulled out all the stops, revving the piece from simply fast to about 50 times faster and changing the time signature from three to four. I imagine Rodgers was turning over in his grave at approximately the same speed.

Onstage, the quintet uses the same format that Benny Goodman established for swinging small groups, which is essentially clarinet and five rhythm pieces, as heard on many of Mr. Peplowski’s early albums for Concord Records. The leader doubles on tenor sax, and the remaining members of the quintet might be said to double as well: Mr. Pizzarelli, who can drive a band so forcefully that the drummer often seems redundant, can solo on the humble, maligned guitar with all the elegance and harmonic sophistication of a great pianist, as he showed on his features, “I Could Write a Book” and “This Nearly Was Mine.” Pianist Derek Smith, a rare swing-based stylist whose specialty is rhythm rather than melody, also plays with such a strong beat that he seems like a second drummer (normally a characteristic of bop and later keyboardists). Bassist David Finck fulfills his customary roll in the background and also, surprisingly for this music, solos on every tune with the melodic presence of a second horn. And drummer Chuck Redd doubles on vibraphone, ecstatically so on “I Didn’t Know What Time It Was,” a title that one shouldn’t take literally in his case, since he obviously knows exactly what the time is, where it is, and what to do with it.

Knowing what we know about Rodgers, he probably wouldn’t have even liked the Peplowski-Pizzarelli Quintet’s exceedingly moving and romantic treatments of ballads, on which they barely departed from the original melodies. Both “Ship Without a Sail” and “Spring Is Here” were rendered mainly by clarinet and bass, with Mr. Peplowski articulating every note so clearly as to conjure the original words to the song; he played the latter tune with a particularly dry, exasperated tone that fully conveyed the melancholy of Hart’s lyric, ending with a super-long, but not at all showy note, via circular breathing.

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Chances are that even Andrea Marcovicci, who is in the second week of a two-month run at the Oak Room, might not have met with Rodgers’s approval, either, despite her clear respect for the composer’s intentions. In “Marcovicci Sings Rodgers & Hart,” she is more musically adventurous than usual, cramming three or four songs into dance-tempo medleys that keep everything lively and cheerful (thank you, Shelly Markham, musical director and piano, and Jered Egan, bass).

God knows, it’s essential to keep everything bright and upbeat in a Rodgers and Hart show, because in presenting the steadily descending arc of Hart’s short, self-destructive life, it’s too easy to make everything a downer and have us all crying in our cabernet. Yet without ever painting a rosy or pious façade on what could be a depressing morality tale, Ms. Marcovicci brings new insights to Hart’s considerable triumphs. The tragedy of his life, as she suggested on Wednesday night, is that he couldn’t identify enough with the subject of his own “My Funny Valentine,” as someone who could be loved in spite of, or even because of, his faults.

From a distance, Ms. Marcovicci is cabaret’s most extravagant drama queen, with her fancy gowns, scads of jewelry, and almost as many costume changes as key changes. She creates the illusion of extreme formality, when in reality her show is precisely the opposite. She unceasingly interacts with everybody in the room, even blessing spectators when they sneeze, and the first thing out of her mouth is not a note of music but a hello to a familiar face.

That’s the starting point from which she proceeds to appeal to the inner song-nerd in all of us (in my case, not so inner). She has also released a complementary CD, “Andrea Marcovicci Sings Rodgers & Hart” (on her own Andreasong label). As you’d expect, Ms. Marcovicci has carefully balanced the 14 tracks among megastandards (such as her opener, “Where or When?”) and lesser-known sleepers that I’ve never heard live, such as the previously exhumed “If I Were You.”

In Ms. Marcovicci’s shows, the context and presentation take priority over the singing itself, but her most important mission is to make the crowd feel like a roomful of her most intimate friends. Rodgers probably wouldn’t have appreciated much of Mr. Peplowski, Mr. Pizzarelli, or Ms. Marcovicci’s efforts, but it would have been his loss.

wfriedwald@nysun.com