aq_ord

Synopsis

aq_ord [-h] Global_Opt Input_Spec Sort_Spec Output_Spec

Global_Opt:
    [-verb] [-stat]

Input_Spec:
    [-f[,AtrLst] File [File ...]] [-d ColSpec [ColSpec ...]]

Sort_Spec:
    -sort[,AtrLst] ColTyp:ColNum | -sort[,AtrLst] ColName [ColName ...]

Output_Spec:
    [-o[,AtrLst] File] [-c ColName [ColName ...]]

Description

aq_ord sorts input records according to the value of the sort columns. Sort is done in memory, so it is fast. However, the entire data set must fit into a single machine’s main memory. The program offers two sort modes. One is fast and simple but less flexible. The other requires more processing overhead but is more versatile.

1. Raw sort mode

   In this mode, raw input rows are stored in memory as-is. Column values are not interpreted except for the sort column. Advantages are:

   • Simple spec. Only need the sort column index and type.
   • Fast. Only the sort column’s value needs to be interpreted.
   • Output rows and input rows are identical because rows are stored as-is.
   • Rows can have varying number of columns as long as the sort column is always at the same position.

   Disadvantages are:

   • Only one sort column.
   • Input cannot be binary (from another aq_* program).
   • Cannot discard unwanted columns from input.
   • Cannot select or reposition columns on output.
   • Cannot output a title row, even if the input has one.
   • Memory intensive. The entire data set must be buffered, plus an additional sort array.

2. Parsed sort mode

   In this mode, a column spec must be defined. Columns are converted before they are stored in memory - numeric and IP address types are stored in binary forms, string type is hashed and the pointer to the hash entry is stored. Advantages are:

   • Support composite sort key.
   • Input can be binary (from another aq_* program). In this format, the input columns need not be converted, so it is more efficient.
   • Can discard unwanted columns from input.
   • Can select and reposition columns on output.
   • Can control output title row.
   • Potentially more memory efficient when string values are repetitive.

   Disadvantages are:

   • More complex spec. Require all column types and names.
   • Slower due to the column conversions during input and output.
   • Output may not resemble the input. For example, an input numeric column of value “” will become “0” on output.
   • May use more memory than the size of the input if strings are mostly unique and numbers are small (e.g., integer values less than 1000).

Options

-verb

Verbose - print program progress to stderr while processing. Usually, a marker is printed for each 10,000,000 records processed.

-stat

Print a record count summary line to stderr at the end of processing. The line has the form:

aq_ord: rec=Count err=Count

-f[,AtrLst] File [File ...]

Set the input attributes and files. See the aq_tool input specifications manual for details.

Example:

$ aq_ord ... -f,+1l file1 file2 ...

• Skip the first line from both files before loading.

-d ColSpec [ColSpec ...]

Optionally define the input data columns. Only needed in Parsed sort mode. See the aq_tool input specifications manual for details. In general, ColSpec has the form Type[,AtrLst]:ColName. Supported Types are:

• S - String.
• F - Double precision floating point.
• L - 64-bit unsigned integer.
• LS - 64-bit signed integer.
• I - 32-bit unsigned integer.
• IS - 32-bit signed integer.
• IP - v4/v6 address.

Optional AtrLst is a comma separated list of column specific attributes. ColName is the column name (case insensitive). It can contain up to 31 alphanumeric and ‘_’ characters. Its first character cannot be a digit.

Example:

$ aq_ord ... -d s:Col1 s,lo:Col2 i,trm:Col3 ...

• Col1 is a string. Col2 is also a string, but the input value will be converted to lower case. Col3 is an unsigned integer, the trm attribute removes blanks around the value before it is converted to an internal number.

-sort[,AtrLst] ColTyp:ColNum

Define the Raw sort mode sort column. ColTyp specifies the sort column’s data type. See -d for a list of types,``X`` is not supported. ColNum specifies the column number (one-based) of the sort column in each row. Optional AtrLst is a comma separated list containing:

• dec - Sort in descending order. Default order is ascending. Descending sort is done by inverting the ascending sort result.

Example:

$ aq_ord ... -sort s:2

• Sort records according to the string value of the 2nd column in ascending order.
• This uses the Raw sort mode, so no column spec is needed.

-sort[,AtrLst] ColName [ColName ...]

Define the Parsed sort mode sort columns. ColNames must already be defined under -d. Optional AtrLst is a comma separated list containing:

• dec - Sort in descending order. Default order is ascending. Descending sort is done by inverting the ascending sort result.

Example:

$ aq_ord ... -d i:Col1 s:Col2 ... -sort Col2 Col1

• Sort records according to the string value of the 2nd column and the numeric value of the 1st column in ascending order.
• This uses Parsed sort mode, so more than one sort column can be specified.

[-o[,AtrLst] File] [-c ColName [ColName ...]]

Output data rows. Optional “-o[,AtrLst] File” sets the output attributes and file. See the aq_tool output specifications manual for details.

In the Raw sort mode, most output attributes have no effect since the records cannot be altered (only their order). The -c option is not applicable either.

In the Parsed sort mode, optional “-c ColName [ColName ...]” selects the columns to output. ColName refers to a column defined under -d. A ColName can be preceeded with a ~ (or !) negation mark. This means that the column is to be excluded. Without -c, all columns are selected by default. If -c is specified without a previous -o, output to stdout is assumed.

Multiple sets of “-o ... -c ...” can be specified.

Example:

$ aq_ord ... -d s:Col1 s:Col2 s:Col3 ... -o,esc,noq - -c Col2 Col1

• Output Col2 and Col1 (in that order) to stdout in a format suitable for Amazon Cloud.

Exit Status

If successful, the program exits with status 0. Otherwise, the program exits with a non-zero status code along error messages printed to stderr. Applicable exit codes are:

• 0 - Successful.
• 1 - Memory allocation error.
• 2 - Command option spec error.
• 3 - Initialization error.
• 4 - System error.
• 5 - Missing or invalid license.
• 11 - Input open error.
• 12 - Input read error.
• 13 - Input processing error.
• 21 - Output open error.
• 22 - Output write error.

See Also

• aq-input - aq_tool input specifications
• aq-output - aq_tool output specifications
• aq_pp - Record preprocessor