text: update user set nickname='alice' where id=1;
  update user set nickname='alice' where name='alice';
  update user set pet='fido' where id=1;
  
  /* update secondary vindex value */
  update user set name='alicia' where id=1;
  update user set name='alicia' where name='alice';
  
  /* scatter update -- supported but with nondeterministic output */
  /* update name_info set has_nickname=1 where nickname != ''; */
  
  /* scatter update autocommit */
  update /*vt+ MULTI_SHARD_AUTOCOMMIT=1 */ name_info set info='apa' where name != 'hog';
  
  /* multi-shard update by secondary vindex */
  update user set pet='rover' where name='alice';
  
  /* update in a transaction on one shard */
  begin;
  update user set nickname='alice' where id=1;
  update user set nickname='bob' where id=1;
  commit;
  
  /* update in a transaction on multiple shards */
  begin;
  update user set nickname='alice' where id=1;
  update user set nickname='bob' where id=3;
  commit;
  
  /* update in a transaction with single query going to multiple shard */
  begin;
  update user set nickname='alice' where id in (1,4);
  commit;
  