岡善博＠中札内です。
テーブルに依って成功する場合と失敗する場合がありますね。
それを判りやすくしました。
alter table XXXXXX ROW_FORMAT= COMPACT;
が成功すると、XXXXXX.ibdが消えているので、コピーしました。

失敗する部分に何かアドバイスは、無いでしょうか？

cp -a /var/db/mysql20210920/zenpakudb.NEW/*.ibd .

# wp_commentmeta
alter table wp_commentmeta ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/wp_commentmeta.ibd .
alter table wp_commentmeta  DISCARD TABLESPACE;

alter table wp_commentmeta IMPORT TABLESPACE;


# wp_comments
alter table wp_comments ROW_FORMAT= COMPACT;
ERROR 1067 (42000): Invalid default value for 'comment_date'
alter table wp_comments DISCARD TABLESPACE;

alter table wp_comments IMPORT TABLESPACE;
ERROR 1808 (HY000): Schema mismatch (Table has ROW_TYPE_DYNAMIC \
row format, .ibd file has ROW_TYPE_COMPACT row format.)


# wp_ktaisession
alter table wp_ktaisession ROW_FORMAT= COMPACT;
ERROR 1067 (42000): Invalid default value for 'expires'
alter table wp_ktaisession DISCARD TABLESPACE;

alter table wp_ktaisession IMPORT TABLESPACE;
ERROR 1808 (HY000): Schema mismatch (Table has ROW_TYPE_DYNAMIC \
row format, .ibd file has ROW_TYPE_COMPACT row format.)


# wp_links
alter table wp_links ROW_FORMAT= COMPACT;
ERROR 1067 (42000): Invalid default value for 'link_updated'
alter table wp_links DISCARD TABLESPACE;

alter table wp_links IMPORT TABLESPACE;
ERROR 1808 (HY000): Schema mismatch (Table has ROW_TYPE_DYNAMIC \
row format, .ibd file has ROW_TYPE_COMPACT row format.)

# wp_options
alter table wp_options ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/wp_options.ibd .
alter table wp_options DISCARD TABLESPACE;

alter table wp_options DISCARD TABLESPACE;



# wp_postmeta
alter table wp_postmeta ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/wp_postmeta.ibd .
alter table wp_postmeta DISCARD TABLESPACE;

alter table wp_options IMPORT TABLESPACE;



# wp_posts
alter table wp_posts ROW_FORMAT= COMPACT;
ERROR 1067 (42000): Invalid default value for 'post_date'
alter table wp_posts DISCARD TABLESPACE;

alter table wp_posts IMPORT TABLESPACE;
ERROR 1808 (HY000): Schema mismatch (Table has ROW_TYPE_DYNAMIC \
row format, .ibd file has ROW_TYPE_COMPACT row format.)


# wp_term_relationships
alter table wp_term_relationships ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/*.ibd .
alter table wp_term_relationships DISCARD TABLESPACE;

alter table wp_term_relationships IMPORT TABLESPACE;



# wp_term_taxonomy
alter table wp_term_taxonomy ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/wp_term_taxonomy.ibd .
alter table wp_term_taxonomy DISCARD TABLESPACE;

alter table wp_term_taxonomy IMPORT TABLESPACE;




# wp_termmeta
alter table wp_termmeta ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/wp_termmeta.ibd .
alter table wp_termmeta DISCARD TABLESPACE;

alter table wp_termmeta IMPORT TABLESPACE;


# wp_terms
alter table wp_terms ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/wp_terms.ibd .
alter table wp_terms DISCARD TABLESPACE;

alter table wp_terms IMPORT TABLESPACE;



# wp_usermeta
alter table wp_usermeta  ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/wp_usermeta.ibd .
alter table wp_usermeta DISCARD TABLESPACE;

alter table wp_usermeta IMPORT TABLESPACE;



# wp_users
alter table wp_users ROW_FORMAT= COMPACT;
ERROR 1067 (42000): Invalid default value for 'user_registered'
alter table wp_users DISCARD TABLESPACE;

alter table wp_users IMPORT TABLESPACE;
ERROR 1808 (HY000): Schema mismatch (Table has ROW_TYPE_DYNAMIC \
row format, .ibd file has ROW_TYPE_COMPACT row format.)


# wp_wpmm_subscribers
alter table wp_wpmm_subscribers ROW_FORMAT= COMPACT;
cp -a /var/db/mysql20210920/zenpakudb.NEW/wp_wpmm_subscribers.ibd .
alter table wp_wpmm_subscribers DISCARD TABLESPACE;

alter table wp_wpmm_subscribers IMPORT TABLESPACE;