zodbanalyze: Add support to analyze a particular range of transaction

Currently zodbanalyze analyzes whole storage. However it becomes
non practical to make a full zodbanalyze run on whole storage because
usually there are many transactions and objects and the time to run full
zodbanalyze is huge.

However, similarly to zodbdump, we can teach zodbanalyze to analyze a
particular range of transactions. This should help to analyze a range of
changes for e.g.  yesterday, or for last week or similar.

/reviewed-on !7

zodbtools/zodbanalyze.py

+# -*- coding: utf-8 -*-
 # Copyright (C) 2002-2017 Zope Foundation + Nexedi + Contributors
 # See LICENSE-ZPL.txt for full licensing terms.
 
@@ -12,7 +13,7 @@ import shutil
 from ZODB.FileStorage import FileIterator, packed_version
 from ZODB.FileStorage.format import FileStorageFormatter
 from ZODB.utils import get_pickle_metadata
-from zodbtools.util import storageFromURL
+from zodbtools.util import storageFromURL, parse_tidrange, ashex
 from golang import func, defer
 
 class DeltaFileStorage(
@@ -73,6 +74,8 @@ class Report:
         self.CBYTESMAP = {}
         self.FOIDSMAP = {}
         self.FBYTESMAP = {}
+        self.tidmin = None  # first scanned transaction
+        self.tidmax = None  # last  ----//----
 
 def shorten(s, n):
     l = len(s)
@@ -91,6 +94,10 @@ def shorten(s, n):
 def report(rep, csv=False):
     delta_fs = rep.delta_fs
     if not csv:
+        if rep.TIDS == 0:
+            print "# ø"
+        else:
+            print "# %s..%s" % (ashex(rep.tidmin), ashex(rep.tidmax))
         print "Processed %d records in %d transactions" % (rep.OIDS, rep.TIDS)
         print "Average record size is %7.2f bytes" % (rep.DBYTES * 1.0 / rep.OIDS)
         print ("Average transaction size is %7.2f bytes" %
@@ -163,13 +170,13 @@ def report(rep, csv=False):
                           rep.FBYTES * 1.0 / rep.FOIDS)
 
 @func
-def analyze(path, use_dbm, delta_fs):
+def analyze(path, use_dbm, delta_fs, tidmin, tidmax):
     if delta_fs:
         fs = DeltaFileStorage(path, read_only=1)
     else:
         fs = storageFromURL(path, read_only=1)
     defer(fs.close)
-    fsi = fs.iterator()
+    fsi = fs.iterator(tidmin, tidmax)
     report = Report(use_dbm, delta_fs)
     for txn in fsi:
         analyze_trans(report, txn)
@@ -179,6 +186,10 @@ def analyze(path, use_dbm, delta_fs):
 
 def analyze_trans(report, txn):
     report.TIDS += 1
+    if report.tidmin is None:
+        # first seen transaction
+        report.tidmin = txn.tid
+    report.tidmax = txn.tid
     for rec in txn:
         analyze_rec(report, rec)
 
@@ -232,7 +243,7 @@ def analyze_rec(report, record):
 
 __doc__ = """%(program)s: Analyzer for ZODB data or repozo deltafs
 
-usage: %(program)s [options] <storage>
+usage: %(program)s [options] <storage> [tidmin..tidmax]
 
 <storage> is an URL (see 'zodb help zurl') or /path/to/file.deltafs(*)
 
@@ -262,6 +273,12 @@ def main(argv):
     except (getopt.GetoptError, IndexError), msg:
         usage(sys.stderr, msg)
         sys.exit(2)
+
+    # parse tidmin..tidmax
+    tidmin = tidmax = None
+    if len(args) > 1:
+        tidmin, tidmax = parse_tidrange(args[1])
+
     csv = False
     use_dbm = False
     for opt, args in opts:
@@ -284,4 +301,4 @@ def main(argv):
                 h.tloc = self._tpos
                 return h
             FileStorageFormatter._read_data_header = _read_data_header
-    report(analyze(path, use_dbm, delta_fs), csv)
+    report(analyze(path, use_dbm, delta_fs, tidmin, tidmax), csv)