Why does my two-column book have column breaks that leave huge empty spaces?

Question

I have the following XeTeX document. You can also view it on ShareLaTeX. I have a two-column layout, and sometimes there is a column break that leaves a very huge empty space.

\documentclass[twocolumn]{book}
\usepackage[bottom=1in]{geometry}

\usepackage{xeCJK}
\setCJKmainfont{SimSun}
\newcommand{\pinyin}[1] {{\sffamily #1}}
\newcommand{\definition}[1] {\textsl{#1}}

\usepackage{supertabular}

\parindent=0pt

\begin{document}

\chapter{}

This chapter contains 10 characters. If you know all 10 characters from the beginning of this book through the end of this chapter, you can \begin{itemize}\item recognize 1.5\% of the characters in Chinese movie subtitles.\item recognize 2.4\% of the characters in Chinese books.\end{itemize}On average, characters in this group will appear in 62.39\% of Chinese movies.
\section{一\hfill yī -- \definition{one}\quad}
\subsection*{Origin}
A single horizontal stroke, representing the number one.\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}一 & \pinyin{yī} & \definition{one; 1; single; a} \\
一一 & \pinyin{yī yī} & \definition{one by one} \\
\end{supertabular}

\section{二\hfill èr -- \definition{two}\quad}
\subsection*{Origin}
Two horizontal strokes, representing the number two.\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}二 & \pinyin{èr} & \definition{two; 2} \\
\end{supertabular}

\section{三\hfill sān -- \definition{three}\quad}
\subsection*{Origin}
Three horizontal strokes, representing the number three.\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}三 & \pinyin{sān} & \definition{three; 3} \\
\end{supertabular}

\section{四\hfill sì -- \definition{four}\quad}
\subsection*{Origin}
In ancient texts the character 亖 (four horizontal strokes) was used. The origin of the current form is unclear.\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}四 & \pinyin{sì} & \definition{four; 4} \\
\end{supertabular}


\end{document}

As you can see, the right column on the first page is almost completely empty except for the subsection heading, and then the content continues on the second page.

Why is this happening and how can I fix this problem?

Note that I'm automatically generating the LaTeX code from a different source, and I'll end up with a few hundred pages, so I'd rather not do anything that requires manual fiddling with page breaks.

Answer 1

I cannot reproduce exactly your MWE because I do not have the SimSun font, but I agree that there is no reason to use supertabular in this MWE.

Besides this, if you cannot leave aside supertabular or your face a similar problem for another reason, causing LaTeX fail to find the best place for page breaks, this could be alleviated to a large extent when you left some stretchable glue between paragraphs skips.

You can use some like \parskip 1em plus 1em minus 1 em (modify 1em to what you find better) or better, use the the parskip package to left a zero \parindent and non-zero \parskip.

\documentclass[twocolumn]{book}
\usepackage{parskip}
\usepackage[bottom=1in]{geometry}
\usepackage{xeCJK}
\newcommand{\pinyin}[1] {{\sffamily #1}}
\newcommand{\definition}[1] {\textsl{#1}}
\usepackage{supertabular}
\begin{document}
\chapter{}
This chapter contains 10 characters. If you know all 10 characters from the beginning of this book through the end of this chapter, you can \begin{itemize}\item recognize 1.5\% of the characters in Chinese movie subtitles.\item recognize 2.4\% of the characters in Chinese books.\end{itemize}On average, characters in this group will appear in 62.39\% of Chinese movies.
\section{一\hfill yī -- \definition{one}\quad}
\subsection*{Origin}
A single horizontal stroke, representing the number one.
\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}一 & \pinyin{yī} & \definition{one; 1; single; a} \\
一一 & \pinyin{yī yī} & \definition{one by one} \\
\end{supertabular}

\section{二\hfill èr -- \definition{two}\quad}
\subsection*{Origin}
Two horizontal strokes, representing the number two.
\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}二 & \pinyin{èr} & \definition{two; 2} \\
\end{supertabular}

\section{三\hfill sān -- \definition{three}\quad}
\subsection*{Origin}
Three horizontal strokes, representing the number three.


\subsection*{Words}

\begin{supertabular}{ r p{1.25cm} p{3.75cm}}三 & \pinyin{sān} & \definition{three; 3} \\
\end{supertabular}

\section{四\hfill sì -- \definition{four}\quad}

\subsection*{Origin}
In ancient texts the character 亖 (four horizontal strokes) was used. The origin of the current form is unclear.
\subsection*{Words}
\begin{supertabular}{ r p{1.25cm} p{3.75cm}}四 & \pinyin{sì} & \definition{four; 4} \\
\end{supertabular}
\end{document}

Answer 2

The document of supertabular says that it checks if there is enough space left and might start a new page accordingly. The problem seems to be a logical flaw concerning the calculation.

The document reads

The TeX register \pagetotal contains the height of the page so far, the LaTeX register \@colroom contains the height of the column.

127 \global\ST@pagesofar\pagetotal    
128 \global\ST@pageleft\@colroom
129 \ST@trace\tw@{Height of text = \the\pagetotal; \MessageBreak
130               Height of page = \the\ST@pageleft}%

Ten lines later

In this case we’re in the second column, so we have to compensate for the material in the first column.

141   \ST@trace\tw@{Second column}%
142   \global\advance\ST@pageleft -\ST@pagesofar
143   \global\advance\ST@pageleft -\@colroom
144 \fi

Since ST@pagesofar is the height of collected materials including those in the first column, there is no need to substract \@colroom.

In your case, the \@colroom is about 500pt and \ST@pagesofar is about 540pt, where the extra 40pt comes from \subsection*{Words}. Then the subtraction reads

1000 - 540 - 500 = -40

which falsely indicates that there is no enough space, new page required.